What is this specific fallacy called?

[BoutsofInsanity]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

[RSP]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

I’m not sure what it’s called, if there is a specific name.

However, I’m not sure that’s the best example as you’re citing two different abilities (skill proficiency vs the Assassin feature) that can accomplish the same thing, just using different means.

Would this be more of what you’re referring to:

The Observant feat allows a character to read lips, therefore, characters without the Observant feat cannot read lips.

[KittenMagician]

im not sure what the specific fallacy is called but another example is proficiencies. because im not proficient with longswords, i cant use them (not true) or because im not proficient with heavy armor i cant wear it (also not true but may interfere with spell casting)

[BoutsofInsanity]

I’m not sure what it’s called, if there is a specific name.

However, I’m not sure that’s the best example as you’re citing two different abilities (skill proficiency vs the Assassin feature) that can accomplish the same thing, just using different means.

Would this be more of what you’re referring to:

The Observant feat allows a character to read lips, therefore, characters without the Observant feat cannot read lips.

Oh the Observant Feat is a good one. That's much better than my example.

EXACTLY THAT THANK YOU. I want to know what it's called. I see it online so freaking often and I just want to be able to be like ---> Fallacy.

[Unoriginal]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

I don't think I've ever seen anyone give this a specific name.

If a name needs to be given, I propose to call it the Explicit Equals Exclusive fallacy.


That being said, it is true that if the version everyone can do is better, as good or even just good enough to make the investment in level/feat/etc not attractive, there is def. a problem in the design, and the investment is def. invalidated. If your lvl 9 ability is just barely better than what anyone can do, it's not a good feeling.

I think 5e did a great job handling this with, for example, the Disarm Manoeuvre vs the Disarm action everyonecan do.

[PhantomSoul]

I think 5e did a great job handling this with, for example, the Disarm Manoeuvre vs the Disarm action everyonecan do.

Similarly, Dash/Disengage/Hide/Dodge vs. Cunning Action (vs. parts of Patient Defense/Step of the Wind), yeah

[fbelanger]

A monopoly!

[Jervis]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

I’ve heard of it called various things but the name I prefer is the rogue fallacy, otherwise known as a anti-feature. Called so because rogues do this in Every. Single. Edition. When they were introduced they suddenly had a monopoly on things like picking locks, climbing, and listening. They also sucked terribly at this, meaning meaning they not only had a monopoly of doing it, but they also had a monopoly on sucking at it. In 3.5 they got Find Traps, who’s existence made the game worse because it meant that no one without it could locate traps with a DC above 20.

[Hael]

I’m not sure what it’s called, if there is a specific name.

The Observant feat allows a character to read lips, therefore, characters without the Observant feat cannot read lips.

Thats kinda like the fallacy known as denying the antecedent.

[stoutstien]

I just call it feature funneling as it's more of a design issue than an logical one. The more explicit features you add to a game the more restrictive the free form portion becomes. DMs can address it on the back end but it's not really the players fault to assume if something is available at an opportunity cost it's also available without one.

[Segev]

The problem it poses is something I call the "Air-Breathing Mermaid" problem.

Imagine mermaids are playable. Then, somewhere, there is a feat that lets them breathe air. Nowhere did it say they couldn't, before, but by creating a feat that "lets" them do so, it implicitly denies mermaids without this feat the ability to do so.

[Telok]

I think 5e did a great job handling this with, for example, the Disarm Manoeuvre vs the Disarm action everyonecan do.

The optional rule in the dmg that most players don't serm to know about? Never seen any dm mention it or players ask about it.

I've always heard of the issue referred to as an 'air breathing mermaid' problem. Its put like this: imagine a game about playing mermaids where everyone happily plays the game for a while having asventures in, on, and out of water. Then a splat is publushed with an ability or feat or some such allowing mermaids to breath air. There's nothing elsewhere in the game talking about mermaids being air breathing or not. What do? And how to deal with the issues of new players using or official content based on the new splat thats coming into previously existing games.

[Witty Username]

The if vs the iff (if and only if) distinction. That is a thing to keep in the back pocket generally, in terms of logic.

As for 5e, it depends on the feature. For example, the thrown weapon style allows the user to draw and throw a weapon as part of the attack action. The normal rules note that drawing a weapon is an object interaction, which can be done once per turn. So this has a defined way of how to play with and without the feature. On the other hand, the hiding rules are described much more generally with the only concrete rules for when you can hide being that you can always hide while invisible. This is relevant for features like Mask of the Wild which allows hiding while lightly obscured. This gives an implication that lightly obscured isn't normally sufficient for hiding, since the features are the only guide for what is allowed and not.

In short, when we have no guidance and class and race features our our only reference points, We use them to map our expectations, even if the truth value of those expectations is nill.

[Naanomi]

Imagine mermaids are playable. Then, somewhere, there is a feat that lets them breathe air. Nowhere did it say they couldn't, before, but by creating a feat that "lets" them do so, it implicitly denies mermaids without this feat the ability to do so.
The 'depth survival' ability of Tritons comes to mind

[diplomancer]

My pet hate in 5e for this subject is Subtle Spell; because Sorcerers get a class feature that allows them to completely eliminate S and V components, no one ever gets to try to disguise those components (without eliminating them completely, assuredly).

[RSP]

Not sure I agree with the mermaid one (though this is my first hearing of it), as, that seems a pretty good indication the original intent was mermaids can’t breathe air, no? It’s a yes or no, whereas other examples can have degrees of ability. Observant might be intended as an auto win on lip reading, while a Perception or Investigation check might be intended to mimic it, but with a chance of failure. But also maybe not.

The mermaid one just sounds like “oh, yeah, we forgot to mention this…”

Perhaps I’m missing something there, though.

[olskool]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

Narrowmindedness. It came into RPGs with the "video gamer" set who were used to rules and limitations. That's why things like FEATS didn't exist in old school AD&D. They were too limiting. I'd allow anyone with PERFORMANCE to do that. One might even question WHO might be better at it, the Assassin or the Bard?

[olskool]

I’m not sure what it’s called, if there is a specific name.

However, I’m not sure that’s the best example as you’re citing two different abilities (skill proficiency vs the Assassin feature) that can accomplish the same thing, just using different means.

Would this be more of what you’re referring to:

The Observant feat allows a character to read lips, therefore, characters without the Observant feat cannot read lips.

My theory on things like that in 5e would be to allow someone WITHOUT the Observant Feat to try to read lips with DISADVANTAGE on the roll.

[Jervis]

My pet hate in 5e for this subject is Subtle Spell; because Sorcerers get a class feature that allows them to completely eliminate S and V components, no one ever gets to try to disguise those components (without eliminating them completely, assuredly).

That’s intentional on there part though. Disguising magic is suppose to be more or less impossible without resource expenditure, it’s been that way in every edition. Otherwise you get things like subtly casting true strike while talking to potential enemies letting you get advantage on the first turn, and that risks making true strike useful, we can’t have true strike being useful now.

Jokes aside this is another thing 3.5 psionics has on its side. If you wanted to make your power not have displays you just had to make a concentration check. It wasn’t trivial mind you but it lets Psionic casters do some interesting things

[Dienekes]

My pet hate in 5e for this subject is Subtle Spell; because Sorcerers get a class feature that allows them to completely eliminate S and V components, no one ever gets to try to disguise those components (without eliminating them completely, assuredly).

I’m not entirely certain if that counts, at least for 5e. The description of spells state that verbal components require a specific pitch and resonance. And somatics are forceful and intricate. With that description I don’t think you were supposed to hide them. You can get the same resonance on a sound if you whisper.

[LumenPlacidum]

The permission-granting feat is essentially...

For all characters c, if the <feature x> is owned by <character c>, then <action y> is doable by <character c>.

That's essentially ∀c, x(c)→y(c).

The other form is: For all characters c, if the <feature x> is NOT owned by <character c>, then <action y> is NOT doable by <character c>.

That's essentially, ∀c, ¬x(c)→¬y(c).

The claim that the two statements are equivalent is, as Hael said, Denying the Antecedent.

[diplomancer]

That’s intentional on there part though. Disguising magic is suppose to be more or less impossible without resource expenditure, it’s been that way in every edition. Otherwise you get things like subtly casting true strike while talking to potential enemies letting you get advantage on the first turn, and that risks making true strike useful, we can’t have true strike being useful now.

Jokes aside this is another thing 3.5 psionics has on its side. If you wanted to make your power not have displays you just had to make a concentration check. It wasn’t trivial mind you but it lets Psionic casters do some interesting things

My go-to example is this: A Bard playing a song, singing and strumming his lute, in a language that's unknown to his audience. Can he cast a spell without them noticing it?

Let's check:
M component. Easiest one; Bards can use musical instruments as foci.
S component: an "intricate set of gestures" (one of the possibilities for S components, by RAW) is exactly what people do when playing an instrument.
V component:
Most spells require the chanting of mystic words. The words themselves aren’t the source of the spell’s power; rather, the particular combination of sounds, with specific pitch and resonance, sets the threads of magic in motion

That's why I chose the song in a different language; if in the middle of a song in a language people are familiar with you suddenly start singing words that are not in that language, people are going to be suspicious, specially in a world where magic is known to exist; but without knowing the language of the song, it's going to be hard to notice those magical "particular combination of sounds, with specific pitch and resonance", between all the other, non-magical "particular combination of sounds, with specific pitch and resonance". Also, as far as I know, there's no such thing in 5e as "the language of magic", so that others would immediately recognize it as something different from the song language if they were spellcasters.

Does this mean that he gets to do it all the time, and no one can ever notice it? No. It's in fact a perfect set-up for a skill context, the Bard's performance skill vs. someone in the crowd's arcana skill (which, incidentally, preserves the Sorcerer's niche; he gets to do it with 100% certainty).

[kazaryu]

The problem it poses is something I call the "Air-Breathing Mermaid" problem.

Imagine mermaids are playable. Then, somewhere, there is a feat that lets them breathe air. Nowhere did it say they couldn't, before, but by creating a feat that "lets" them do so, it implicitly denies mermaids without this feat the ability to do so.

you're not really talking about the same thing as the OP. the OP is talking about when *that* logic is applied improperly. Not when features are introduced that retroactively change how the game is played. to use the mermaids analogy: they're talking about if instead a feat was introduced that gave mermaids a swim speed of 60 feet, and as a result people assume that now mermaids can't swim at all without that feat.

[Segev]

you're not really talking about the same thing as the OP. the OP is talking about when *that* logic is applied improperly. Not when features are introduced that retroactively change how the game is played. to use the mermaids analogy: they're talking about if instead a feat was introduced that gave mermaids a swim speed of 60 feet, and as a result people assume that now mermaids can't swim at all without that feat.

More specifically, as if there were no printed rules for anybody to swim, and now mermaids get a swim speed. Does that mean only mermaids can swim?

[Witty Username]

My theory on things like that in 5e would be to allow someone WITHOUT the Observant Feat to try to read lips with DISADVANTAGE on the roll.

I would go the other way, perception could allow lip reading with a successful check, but lip reading from Observant has no roll.

[Dr.Samurai]

I think it's less a fallacy and more a failure of... imagination, maybe? I don't want to be too harsh.

It's more that if a class feature grants X and X isn't really called out in skills or other traits, then a DM might be reluctant to allow something similar because they feel they are giving a class feature away for the sake of a skill proficiency or improvised ability check.

But I think if it was more intuitive or spelled out in the books that others may try similar things but have to actually make a check (instead of auto-succeed with resource expenditure, as an example) then they can do it too.

I think it just needs to be spelled out a little better.

[Kane0]

I call it mermaid syndrome, because once upon a time there was a mermaid added in a subsequent monster manual that could breathe both air and water, which retroactively meant many things before it couldnt.

Edit: or im misremembering and all credit goes to Segev for planting the seed.

[RSP]

I think it's less a fallacy and more a failure of... imagination, maybe? I don't want to be too harsh.

It's more that if a class feature grants X and X isn't really called out in skills or other traits, then a DM might be reluctant to allow something similar because they feel they are giving a class feature away for the sake of a skill proficiency or improvised ability check.

But I think if it was more intuitive or spelled out in the books that others may try similar things but have to actually make a check (instead of auto-succeed with resource expenditure, as an example) then they can do it too.

I think it just needs to be spelled out a little better.

Depends, and can go both ways. A Rogue’s Expertise is essentially an increased floor in skill checks, so anyone with a good roll can generally duplicate the ability making it less valuable.

Whereas you can’t duplicate Extra Attack in the same way.

And there’s definitely a divide (at least as I see it). I’d be a lot more allowing of a nat 20 on a skill check doing impressive things, than I would be allowing someone without EA to make EAs.

Stuff like the lip reading auto success vs requires a roll falls in the grey middle.

[gloryblaze]

I call it mermaid syndrome, because once upon a time there was a mermaid added in a subsequent monster manual that could breathe both air and water, which retroactively meant many things before it couldnt.

Edit: or im misremembering and all credit goes to Segev for planting the seed.

The "air-breathing mermaid" (https://rpg.stackexchange.com/questions/156876/origin-of-air-breathing-mermaid-charm) problem is definitely a piece of apocryphal TTRPG wisdom that's been floating around the internet for a couple years at least. From my understanding, though, it's more about the game design end of things and not "adding" new features in splat that were previously assumed to be baseline competency (whereas the phenomenon being described in the OP could happen even in a game with no splat; i.e. Subtle Spell was printed right in the PHB1).

1Though I actually am one of the people who prefers disguised spellcasting to be exclusively the domain of Subtle Spell, just because I think having spellcasting be obvious is good for the game world, but I know that can be contentious. Just running with an example used upthread.

[Ganryu]

I'd say it's a False Dichotomy. It's black or white. It has this, therefore, everything that does, doesn't.

Side note, this is a really useful video on fallacies.

31 logical fallacies in 8 minutes - YouTube (https://www.youtube.com/watch?v=Qf03U04rqGQ&ab_channel=JillBearup)

[kazaryu]

More specifically, as if there were no printed rules for anybody to swim, and now mermaids get a swim speed. Does that mean only mermaids can swim?

right, thats another good example, or it can be. and the answer would be based on how a swim speed is defined...But the problem that, i believe the OP asked about is when everyone just kinda assumes that noone else can swim, even if the rules to don't forbid it.

[GeoffWatson]

S component: an "intricate set of gestures" (one of the possibilities for S components, by RAW) is exactly what people do when playing an instrument.

So all spellcasting has the Wizards and Clerics doing "air guitar"?

I'd guess each spell has it's own "intricate set of gestures", not that you can use any "ISOG" that just so happens to match what you were already doing.

[PhoenixPhyre]

So all spellcasting has the Wizards and Clerics doing "air guitar"?

I'd guess each spell has it's own "intricate set of gestures", not that you can use any "ISOG" that just so happens to match what you were already doing.

Right. Think Naruto ninja hand signs. The idea is that every spell has a fixed set of gestures, sounds (in an obviously arcane phrasing, one that doesn't actually sound like normal words), etc. They might be unique to the spell (for all casters) or might be unique to the person, but by default they can't really be mistaken for anything else but a spell by anyone who is in a position to perceive the casting.

[kazaryu]

So all spellcasting has the Wizards and Clerics doing "air guitar"?

I'd guess each spell has it's own "intricate set of gestures", not that you can use any "ISOG" that just so happens to match what you were already doing.

well, technically not all. i mean, all spells have either a v or an S component (i think). but not all have both.


Right. Think Naruto ninja hand signs. The idea is that every spell has a fixed set of gestures, sounds (in an obviously arcane phrasing, one that doesn't actually sound like normal words), etc. They might be unique to the spell (for all casters) or might be unique to the person, but by default they can't really be mistaken for anything else but a spell by anyone who is in a position to perceive the casting.

this isn't strictly true. at least not by RaW.
somatic just requires 'a forceful gesticulation, or perhaps a series of intricate moves'.

and verbal just requires 'chanting mystical words' but its clarified that the words aren't important, its the sounds of the spells.

at least for the somatic component, nothing precludes those movements from being passed off as something else inherently. its just that, by default, it will be recognized as casting.

[GeoffWatson]

well, technically not all. i mean, all spells have either a v or an S component (i think). but not all have both.



this isn't strictly true. at least not by RaW.
somatic just requires 'a forceful gesticulation, or perhaps a series of intricate moves'.

and verbal just requires 'chanting mystical words' but its clarified that the words aren't important, its the sounds of the spells.

at least for the somatic component, nothing precludes those movements from being passed off as something else inherently. its just that, by default, it will be recognized as casting.

Cool! My elf will pass his somatic components as "shooting a bow", that requires "intricate moves", right? Free extra shots! Oh, and some spells have "stab with rapier" as the somatics, just in case.

[diplomancer]

Right. Think Naruto ninja hand signs. The idea is that every spell has a fixed set of gestures, sounds (in an obviously arcane phrasing, one that doesn't actually sound like normal words), etc. They might be unique to the spell (for all casters) or might be unique to the person, but by default they can't really be mistaken for anything else but a spell by anyone who is in a position to perceive the casting.

This may be your idea, and the idea of many DMs, but it's not what the PHB says; no such thing as "obviously arcane phrasing" or "fixed set of gestures" in the text.


So all spellcasting has the Wizards and Clerics doing "air guitar"?

I'd guess each spell has it's own "intricate set of gestures", not that you can use any "ISOG" that just so happens to match what you were already doing.

There's nothing in the rules that says the Somatic component of a particular spell is always the same, regardless of who's casting it (with a few notable-and contentious- exceptions, like Burning Hands).

Furthermore, you are not understanding exactly what the Bard's doing; he chose that particular song because he wanted to cast the particular spell: it's not "by chance" that the gestures for the spell are the "chord positions" for his lute.




Though I actually am one of the people who prefers disguised spellcasting to be exclusively the domain of Subtle Spell, just because I think having spellcasting be obvious is good for the game world, but I know that can be contentious. Just running with an example used upthread.

Fair enough, and reasonable. But I've seen many times the argument that if you allow for disguised casting, you're messing up the Sorcerer's Subtle Spell, and that's why you can't have it. So, in my opinion:
1- disallowing disguised casting as a worldbuilding decision: does not run afoul of this fallacy
2- disallowing disguised casting because Subtle Spell exists: runs afoul of this fallacy.

[Kane0]

Fair enough, and reasonable. But I've seen many times the argument that if you allow for disguised casting, you're messing up the Sorcerer's Subtle Spell, and that's why you can't have it. So, in my opinion:
1- disallowing disguised casting as a worldbuilding decision: does not run afoul of this fallacy
2- disallowing disguised casting because Subtle Spell exists: runs afoul of this fallacy.

Messing up subtle spell maybe, but I would say that considering it as a balance concern isnt a fallacy.

[Segev]

The problem most often arises when there is no definite mechanical way to do something, but it was or could have been assumed to fall under another general mechanic (or simply be doable without special rules), and then something comes along and says, "Those with this special thing can do this specific thing."

Assassins have a feature that lets them make impersonations and personnas. Some may have ruled that anybody making disguise checks and deception checks can do that. Others may have struggled to figure out how to rule if a player asked to do so. But since it is a class feature of the Assassin, it seems to remove it from the realm of being a thing anybody can do. After all, what's the point of a feature that lets you do what you already could do without it?

There are solid arguments for how the Assassin does this automatically without rolling, but that still feels...lackluster...to many. Similarly, Observant doesn't say you automatically succeed on checks to read lips, but rather that you can read them, as if that were a power others simply lack. Add in my usual complaints about the skill system leaving us with no idea how hard reading lips should be without the feat, and the fact that the feat failing to say you automatically succeed could bring it back to requiring the same check anybody could make, and it is messy if you don't rule that you can read lips if and only if you have the Observant feat.

This doesn't mean that is the right ruling; this is an explanation of the morass of subconscious reasons that might convince any given reader that you can read lips iff you have the Observant feat.

Is it a fallacy? Unfortunately, we have things that are given as features that ARE exclusive, and not generally available. Nobody but a Barbarian can fly into a rage to gain combat and strength benefits. (Or, if they can, why not play a class that gives things other than rage and also gain rage benefits? Especially since you're not limited in how often per day you can do it unless you have the feature that limits you!)

This also doesn't mean it truly is always how you should read such rules.

It's tricky.

[RSP]

(with a few notable-and contentious- exceptions, like Burning Hands)

If you’re referring to “As you hold your hands with thumbs touching and fingers spread” in BH, that’s part of the spell effect, not the components.

It is interesting though, that if you’re holding a shield, or whatever, in one hand (or both, for that matter), the spell effect has your hands magically do this.

[tokek]

My pet hate in 5e for this subject is Subtle Spell; because Sorcerers get a class feature that allows them to completely eliminate S and V components, no one ever gets to try to disguise those components (without eliminating them completely, assuredly).

The descriptions of verbal and somatic components are clearly worded to make it just about impossible to do what a lot of players attempt. Which is just "say it more quietly" or "do a tiny gesture they can't notice". So I'd say a lot of the discussion around "Just get Subtle Spell" is valid.

Not to say that there is no possible way. After all if you were to have an illusion spell up that distracted and diverted everything - then that's different. Hiding behind an illusory wall that only you can see through is quite an effective tactic but its situational and requires preparation.

[Vahnavoi]

There's actually three things that may be going on here at once:

1) Inverse error / denying the antecedent
2) Specific trumps general
3) Exception proves the rule

Only the first is strictly a fallacy, the other two are overarching principles for rule interpretation. Bad application of the latter two can directly lead to the first, though.

Let's look at these in order:

1) Inverse error: "A thief can sneak attack. I am not a thief. Therefore I can't sneak attack." Both premises are correct, but they are not sufficient for the conclusion, because there might be a way to sneak attack that doesn't require being a thief.

2) Specific trumps general: there is a hierarchy of rules. There are basic rules and special rules and when the two are in conflict, the special rules are followed over the basic ones. So if basic rules say a surprise attack gets you +2 to hit, and rules specific to thieves say a surprise attack counts as a sneak attack, when a thief makes a surprise attack, you adhere to rules of sneak attacks.

3) Exception proves the rules: special exceptions imply general rules are followed outside those exception. So if rules say thief's surprise attack counts as a sneak attack, this implies other attacks don't count as sneak attacks.

Out of these, 2) and 3) put together create the "air-breathing mermaid problem". Said problem is not a fallacy. It is an issue of bad game design. Specifically: a rule set was constructed following 2). It was silent on whether mermaids could breathe air. Since under basic rules all characters could breathe air, the straight-forward interpretation was that mermaids could breathe air too. Then some clueless mofo added in a special rule, in the format of a feat (etc.), that says it allows mermaids to breathe air. Since specific trumps general, addition of such a rule in such a format is only necessary if the general rule is that mermaids cannot breathe air. This leads, via direct application of 3), to the implication that mermaids without the feat cannot breathe air, reversing previous rule interpretation.

So. Back to 1). In D&D, class features and such are typically presented to players in a format that implicitly or explicitly follows 2). They are presented as special permissions to do something others cannot. They typically do no give any constructive formulation for achieving the same things in other ways. This, via application of 3), leads to interpretation that such things cannot be done in absence of such special permission. It is up to the game master to show where in the basic rules alternate methods are allowed to achieve the same effects.

[noob]

The problem most often arises when there is no definite mechanical way to do something, but it was or could have been assumed to fall under another general mechanic (or simply be doable without special rules), and then something comes along and says, "Those with this special thing can do this specific thing."

Assassins have a feature that lets them make impersonations and personnas. Some may have ruled that anybody making disguise checks and deception checks can do that. Others may have struggled to figure out how to rule if a player asked to do so. But since it is a class feature of the Assassin, it seems to remove it from the realm of being a thing anybody can do. After all, what's the point of a feature that lets you do what you already could do without it?

There are solid arguments for how the Assassin does this automatically without rolling, but that still feels...lackluster...to many. Similarly, Observant doesn't say you automatically succeed on checks to read lips, but rather that you can read them, as if that were a power others simply lack. Add in my usual complaints about the skill system leaving us with no idea how hard reading lips should be without the feat, and the fact that the feat failing to say you automatically succeed could bring it back to requiring the same check anybody could make, and it is messy if you don't rule that you can read lips if and only if you have the Observant feat.

This doesn't mean that is the right ruling; this is an explanation of the morass of subconscious reasons that might convince any given reader that you can read lips iff you have the Observant feat.

Is it a fallacy? Unfortunately, we have things that are given as features that ARE exclusive, and not generally available. Nobody but a Barbarian can fly into a rage to gain combat and strength benefits. (Or, if they can, why not play a class that gives things other than rage and also gain rage benefits? Especially since you're not limited in how often per day you can do it unless you have the feature that limits you!)

This also doesn't mean it truly is always how you should read such rules.

It's tricky.

To be fair if you are not an assassin and trying to make an alternate identity and roll a skill for it, the roll would be hidden from you: someone does not necessarily knows the mistakes they did in forming an alternate identity.
So if you are not an assassin you will be constantly doubting you did the job good and worrying thus adding some constant dread and pressure.(and it would be opposable by other skill checks)
and that is not due to the existence of assassins: it is because such mechanic does adds an interesting way to apply constant psychological pressure on the players.

[Slipjig]

I'm not sure that's actually a fallacy, I'd say it's more a matter of a mismatch between the designers' and the players' assumption about general PC competence.

Thr game designers start with the assumption that most people cannot read lips. IRL, most people can't read lips, so it's reasonable to assume that PCs cannot do so unless they have the ability granted by a specific feature like the Observant feat.

The Assassin feature seems like a problem, though: making it a class feature strongly implies that the designers don't think that people should be able to do this without special training. However, it's reasonable to assume that MOST people could establish some degree of false identity by buying some new clothes and introducing themselves to strangers under a false name. But allowing this clearly devalues the Assassin's class feature.

[OldTrees1]

There's actually three things that may be going on here at once:

1) Inverse error / denying the antecedent
2) Specific trumps general
3) Exception proves the rule

Only the first is strictly a fallacy, the other two are overarching principles for rule interpretation. Bad application of the latter two can directly lead to the first, though.

Let's look at these in order:

1) Inverse error: "A thief can sneak attack. I am not a thief. Therefore I can't sneak attack." Both premises are correct, but they are not sufficient for the conclusion, because there might be a way to sneak attack that doesn't require being a thief.

2) Specific trumps general: there is a hierarchy of rules. There are basic rules and special rules and when the two are in conflict, the special rules are followed over the basic ones. So if basic rules say a surprise attack gets you +2 to hit, and rules specific to thieves say a surprise attack counts as a sneak attack, when a thief makes a surprise attack, you adhere to rules of sneak attacks.

3) Exception proves the rules: special exceptions imply general rules are followed outside those exception. So if rules say thief's surprise attack counts as a sneak attack, this implies other attacks don't count as sneak attacks.

Hmm. D&D uses several open ended general resolution mechanics (ability checks for example). What advice would you give game developers if they wanted Specific trumps general, and class features, and an open ended general resolution system, but did not want the Inverse error?

[PhoenixPhyre]

Exceptions don't prove that a rule exists. Exceptions test the rule, if it exists. And specific rules may or may not be overriding general rules.

I think the most common error is reasoning from specific rules. You can't. The existence of a specific rule gives no evidence in either direction for the existence of a general rule. Every specific rule stands alone unless it necessarily interacts with another rule, and interaction of rules should be disfavored unless necessary. Some of them restate general rules as part of their text. Others address issues not stated in any general rule.

The game rules are not complete, by construction and by intention. You can't play the game by RAW only. And that's intentional.

[Vahnavoi]

@PhoenixPhyre: reasoning from specific rules is not an error when a rule corpus is constructed following one or both of the aforementioned principles. F.ex. when a sign says "parking costs money between 06:00 - 16:00", it is correct to infer that parking is free outside of that timespan. Don't confuse other versions of the saying for what is being used here.

---

@OldTrees1: I would tell them to choke on a stick.

More seriously, the problem cannot be fixed without additional principles of rule interpretation. I would try: "No penalty without crime and no crime without a law defining it" ==> "Any action can be attempted if it has not specifically been prohibited", combined with good old "game master as referee has final say over game matters".

[Pex]

Pathfinder had a similar problem where it was called "You need a feat for that." You couldn't do something unless you had a feat. It started rather benign that having the feat only meant you didn't suffer an attack of opportunity for attempting the thing. Anyone without the feat can try it, just suffer an attack of opportunity. Some feats then gave bonuses to the roll. Because of game statistics you needed that bonus to have a decent chance of success. Without the feat and thus the bonus your chance of success was near nil and you suffered an attack of opportunity. It wasn't worth the attempt.

Then it got worse. Having the feat meant you could do something. That's what the feat did, so not having the feat meant you couldn't do it. Period. An infamous case had the players (including DMs) scream bloody murder. Since at least the beginning of 3.0, when it started, players wanted and DMs enthusiastically allowed the option to use Diplomacy during combat to get the enemy to surrender or parley or agree it's a draw and peace out or whatever to end the combat instead of one side killing everyone on the other side. Everyone was doing it without issue. No one complained it was possible. No one complained if a DM decided nah, not for his game or maybe just nah, not for these particular bad guys because they're fanatical but ok in general. Then, one day, Pathfinder had the idea to publish a feat that specifically allowed the PC to use Diplomacy in this way. Thus it was implied that from now on, anyone without that feat could never use Diplomacy to get the enemy to surrender, parley, or peace out. The feat was universally condemned and ignored.

[tanonx]

Cool! My elf will pass his somatic components as "shooting a bow", that requires "intricate moves", right? Free extra shots! Oh, and some spells have "stab with rapier" as the somatics, just in case.

Sure. Doubtless this is a special school of magic you specialize in.

After all, you won't be getting any attacks (those are Attack actions, after all). You just have to make violent, sweeping gestures with each spell, and maybe burn an arrow each time (these are precise gestures you've asked for, after all, can't short you on that). Enjoy the murder mystery campaign.

[Kane0]

There's actually three things that may be going on here at once:

1) Inverse error / denying the antecedent
2) Specific trumps general
3) Exception proves the rule

Only the first is strictly a fallacy, the other two are overarching principles for rule interpretation. Bad application of the latter two can directly lead to the first, though.

Let's look at these in order:

1) Inverse error: "A thief can sneak attack. I am not a thief. Therefore I can't sneak attack." Both premises are correct, but they are not sufficient for the conclusion, because there might be a way to sneak attack that doesn't require being a thief.

2) Specific trumps general: there is a hierarchy of rules. There are basic rules and special rules and when the two are in conflict, the special rules are followed over the basic ones. So if basic rules say a surprise attack gets you +2 to hit, and rules specific to thieves say a surprise attack counts as a sneak attack, when a thief makes a surprise attack, you adhere to rules of sneak attacks.

3) Exception proves the rules: special exceptions imply general rules are followed outside those exception. So if rules say thief's surprise attack counts as a sneak attack, this implies other attacks don't count as sneak attacks.

Out of these, 2) and 3) put together create the "air-breathing mermaid problem". Said problem is not a fallacy. It is an issue of bad game design. Specifically: a rule set was constructed following 2). It was silent on whether mermaids could breathe air. Since under basic rules all characters could breathe air, the straight-forward interpretation was that mermaids could breathe air too. Then some clueless mofo added in a special rule, in the format of a feat (etc.), that says it allows mermaids to breathe air. Since specific trumps general, addition of such a rule in such a format is only necessary if the general rule is that mermaids cannot breathe air. This leads, via direct application of 3), to the implication that mermaids without the feat cannot breathe air, reversing previous rule interpretation.

So. Back to 1). In D&D, class features and such are typically presented to players in a format that implicitly or explicitly follows 2). They are presented as special permissions to do something others cannot. They typically do no give any constructive formulation for achieving the same things in other ways. This, via application of 3), leads to interpretation that such things cannot be done in absence of such special permission. It is up to the game master to show where in the basic rules alternate methods are allowed to achieve the same effects.
I think this is a good explanation.



Pathfinder had a similar problem where it was called "You need a feat for that."
That gave me a gaming-PTSD flashback.

[BoutsofInsanity]

There's actually three things that may be going on here at once:

1) Inverse error / denying the antecedent
2) Specific trumps general
3) Exception proves the rule

Only the first is strictly a fallacy, the other two are overarching principles for rule interpretation. Bad application of the latter two can directly lead to the first, though.

Let's look at these in order:

1) Inverse error: "A thief can sneak attack. I am not a thief. Therefore I can't sneak attack." Both premises are correct, but they are not sufficient for the conclusion, because there might be a way to sneak attack that doesn't require being a thief.

2) Specific trumps general: there is a hierarchy of rules. There are basic rules and special rules and when the two are in conflict, the special rules are followed over the basic ones. So if basic rules say a surprise attack gets you +2 to hit, and rules specific to thieves say a surprise attack counts as a sneak attack, when a thief makes a surprise attack, you adhere to rules of sneak attacks.

3) Exception proves the rules: special exceptions imply general rules are followed outside those exception. So if rules say thief's surprise attack counts as a sneak attack, this implies other attacks don't count as sneak attacks.

Out of these, 2) and 3) put together create the "air-breathing mermaid problem". Said problem is not a fallacy. It is an issue of bad game design. Specifically: a rule set was constructed following 2). It was silent on whether mermaids could breathe air. Since under basic rules all characters could breathe air, the straight-forward interpretation was that mermaids could breathe air too. Then some clueless mofo added in a special rule, in the format of a feat (etc.), that says it allows mermaids to breathe air. Since specific trumps general, addition of such a rule in such a format is only necessary if the general rule is that mermaids cannot breathe air. This leads, via direct application of 3), to the implication that mermaids without the feat cannot breathe air, reversing previous rule interpretation.

So. Back to 1). In D&D, class features and such are typically presented to players in a format that implicitly or explicitly follows 2). They are presented as special permissions to do something others cannot. They typically do no give any constructive formulation for achieving the same things in other ways. This, via application of 3), leads to interpretation that such things cannot be done in absence of such special permission. It is up to the game master to show where in the basic rules alternate methods are allowed to achieve the same effects.

I'd agree that this is a good explanation for it too. It's difficult to put into words because it's a fundamental way to view the D&D game and I would guess that it's not an incorrect interpretation (Even if I think it's incorrect to be restrictive in this way). There is a lot going on there and I wish I had a term like "Stormwind Fallacy" to immediately throw out to make my point without having to type 3 paragraphs of text.

[OldTrees1]

@OldTrees1: I would tell them to choke on a stick.

More seriously, the problem cannot be fixed without additional principles of rule interpretation. I would try: "No penalty without crime and no crime without a law defining it" ==> "Any action can be attempted if it has not specifically been prohibited", combined with good old "game master as referee has final say over game matters".

I am missing some context for the joke.

That is a good answer. Make it explicit that the general resolution systems allow for anything not explicitly prohibited. Then you can make specific rules that either make something prohibited (Rogue Sneak Attack requires advantage or an ally) or that specifically allows skipping the general resolution system (Assassin can disguise themselves).

Thank you for the good initial answer and the advice for game devs.

[BoutsofInsanity]

I am missing some context for the joke.

That is a good answer. Make it explicit that the general resolution systems allow for anything not explicitly prohibited. Then you can make specific rules that either make something prohibited (Rogue Sneak Attack requires advantage or an ally) or that specifically allows skipping the general resolution system (Assassin can disguise themselves).

Thank you for the good initial answer and the advice for game devs.

Personally I think this is the intended interpretation that the Dev's had in mind for 5e. All of their videos, interviews and such point to such designs.

I think Observant Feat is a perfect example of how a DM should rule this right?

Observant - You can read lips. Therefore, to read lips, so long as you can see the lips you just can as if you were hearing them. No roll required.

Without Observant you would say - Make a wisdom check (Perception or Insight) against a DC to read lips and know what was being said.

Like without a feature - You incur a cost and a chance of failure or increased chance of failure, versus a class feature or feat that enables you to do such a thing. It's a tough nut to crack.

[PhoenixPhyre]

@PhoenixPhyre: reasoning from specific rules is not an error when a rule corpus is constructed following one or both of the aforementioned principles. F.ex. when a sign says "parking costs money between 06:00 - 16:00", it is correct to infer that parking is free outside of that timespan. Don't confuse other versions of the saying for what is being used here.


Sure. But D&D is not, nor has it ever been designed along those principles. There's another state other than "explicitly forbidden" and "explicitly allowed". D&D rules (and especially 5e) are not designed to be complete. Most things are indeterminate (as far as the rules are concerned). Neither forbidden by them nor allowed by them. And that's intentionally so. Only in a binary "anything not specifically mentioned is forbidden" world does that paradigm hold and you can reason from specifics. And that world isn't D&D.

And there's not indication that all specific rules are exceptions. Very much not the case here. They're just cases that hold in this one area. They say nothing about the terrain outside (and cannot, because that's not how it works). Specific beats general...if and only if there is
a) a general rule and a specific rule that discuss the same area
b) and the two conflict.

It's not anything else. For example, the fact that some spells say that you need to see your target says nothing about any other spell. It's not stating a general rule, it's not overriding a general rule. There is no general rule that says either that you do or do not need to see your target. It's unspecified. The statement "you need to see your target to cast a spell at them" is neither true nor false, it's mu. It has no truth value at all.

------------

On a different note, you can't (validly) reason from one specific rule to another. Each specific rule only contains its own context. It doesn't influence the reading of anything else unless it says it does (or requires doing so in order to function).

[tokek]

Personally I think this is the intended interpretation that the Dev's had in mind for 5e. All of their videos, interviews and such point to such designs.

I think Observant Feat is a perfect example of how a DM should rule this right?

Observant - You can read lips. Therefore, to read lips, so long as you can see the lips you just can as if you were hearing them. No roll required.

Without Observant you would say - Make a wisdom check (Perception or Insight) against a DC to read lips and know what was being said.

Like without a feature - You incur a cost and a chance of failure or increased chance of failure, versus a class feature or feat that enables you to do such a thing. It's a tough nut to crack.

This is very much how the good DMs run things

There is a heuristic that if a thing exists as a class feature or feat then it may be possible for others to do it but it will be harder, there may be pre-requisites and there will be more failure points.

The key word in the rogue assassin ability is "unfailingly". There is no chance of failure. A different character with proficiency with disguise, forgery etc can certainly attempt it but there will be one or more chance for it to fail and there may be risky steps involved such as stealing blank documents as the basis for a forgery.

[greenstone]

I thought the term "spotlight stealing" applied, but my google-fu can't find anything on it so perhaps I made it up.

For example:

GM: <lets character A read lips>
Player of character B: Hang on, I took a feat to allow me to read lips, but you're letting A do it for free? What's up with that?

It is reasonable that if a class/background/wheatever gets a feature, then others should either not be allowed the feature or have to pay a larger cost to get it because that would be stealing the spotlight from the player.

The fallacy is when you refuse to admin the "or have to pay a larger cost" part of the idea.

As posted above:
Fallacy: Observant feat lets you read lips, no roll. Characters without the feat can't read lips.

Correct: Observant feat lets you read lips, no roll. Characters without the feat can read lips, but they must make a roll of some kind.

[Telok]

Correct: Observant feat lets you read lips, no roll. Characters without the feat can read lips, but they must make a roll of some kind.

Well, does it say that you're automatically successful or is the "can" language that some people interpret as permission to try to do something? Because I've seen certain people logic "extra attack is 'can make more attacks', but it doesnt say you auto hit so <thing> says you can but you have to roll".

[Frogreaver]

LetÂ’s make this all proper.

Sometimes the rules allow. Sometimes they forbid. Sometimes they are silent.

Unlike closed games where all allowable moves and their chances for success are accounted for in the rules, d&d grants the dm the power to determine whether the moves itÂ’s silent are disallowed and he can do so for whatever reason he chooses. Thus, for d&d itÂ’s not a fallacy if the dm disallows your level 20 champion fighrer from casting the 9th level spell foresight just because he lacks any ability that says he can. ThatÂ’s fine gaming. So whatÂ’s the difference between spell casting and other class abilities? Skill checks and meant to allow for most non-magical abilities. But even then the game gives the dm power to determine what is and is t possible via ability checks. Perhaps reading lips is determined to be beyond normal capabilities without specific training just for that. Thus the dm can legitimately disallow someone from doing that with a skill check without commuting any fallacy.

This thread to me sounds more like a players attempt to force or persuade a dm to rule in his favor by falsely referring to what is rightfully the DMs ruling as a fallacy.

[PhoenixPhyre]

LetÂ’s make this all proper.

Sometimes the rules allow. Sometimes they forbid. Sometimes they are silent.

Unlike closed games where all allowable moves and their chances for success are accounted for in the rules, d&d grants the dm the power to determine whether the moves itÂ’s silent are disallowed and he can do so for whatever reason he chooses. Thus, for d&d itÂ’s not a fallacy if the dm disallows your level 20 champion fighrer from casting the 9th level spell foresight just because he lacks any ability that says he can. ThatÂ’s fine gaming. So whatÂ’s the difference between spell casting and other class abilities? Skill checks and meant to allow for most non-magical abilities. But even then the game gives the dm power to determine what is and is t possible via ability checks. Perhaps reading lips is determined to be beyond normal capabilities without specific training just for that. Thus the dm can legitimately disallow someone from doing that with a skill check without commuting any fallacy.

This thread to me sounds more like a players attempt to force or persuade a dm to rule in his favor by falsely referring to what is rightfully the DMs ruling as a fallacy.

Agreed. Unlike a board game, everything not explicitly permitted is not forbidden. But yet the reverse is also not true--not everything not forbidden by the rules is allowed[1]. There's that third category you mention. Which, in my experience, makes up all the interesting parts.

[1] WAY too many negatives in these two sentences.

[Vahnavoi]

Sure. But D&D is not, nor has it ever been designed along those principles.

Now you're living in a weird alternate world where WotC never bought D&D.

D&D has worked on exception-based rule engine for the whole d20 era. Errata and sage advice for the third edition repeatedly appealed to "specific trumps general" and fourth edition made it explicit in the basic rules. If I put variation of the phrase on Google, I get this. (https://mobile.twitter.com/JeremyECrawford/status/1128448155391905793?ref_src=twsrc%5Etfw) Based on date, I presume this is about 5th edition, I don't own 5th edition books so I can't easily check.

The supposed open or incomplete nature of D&D matters not, WotC has always written character abilities like they're Magic: the Gathering cards, changing rules of the base game. The insanity begins when rules for character abilities seem appeal to general rules that are indetermined or non-existing. This very much occurs with spells, regenerate is a good example. It gives ability to regenerate limbs, in a system that does not have rules for losing limbs anywhere. The spell is proof that limb loss can occur (otherwise why have the effect?) but it's completely non-constructive.

[PhoenixPhyre]

Now you're living in a weird alternate world where WotC never bought D&D.

D&D has worked on exception-based rule engine for the whole d20 era. Errata and sage advice for the third edition repeatedly appealed to "specific trumps general" and fourth edition made it explicit in the basic rules. If I put variation of the phrase on Google, I get this. (https://mobile.twitter.com/JeremyECrawford/status/1128448155391905793?ref_src=twsrc%5Etfw) Based on date, I presume this is about 5th edition, I don't own 5th edition books so I can't easily check.

The supposed open or incomplete nature of D&D matters not, WotC has always written character abilities like they're Magic: the Gathering cards, changing rules of the base game. The insanity begins when rules for character abilities seem appeal to general rules that are indetermined or non-existing. This very much occurs with spells, regenerate is a good example. It gives ability to regenerate limbs, in a system that does not have rules for losing limbs anywhere. The spell is proof that limb loss can occur (otherwise why have the effect?) but it's completely non-constructive.

Specific trumps general does not imply (as I've already stated) that specific implies general. That's utterly not part of the system. And it has to be to make your argument meaningful. All it means is that IF
a) there is a specific rule and a general rule covering the same condition
b) and they are in conflict
THEN the specific one wins.

Both must be true. But you can have general rules that are not overriden by any specific rules. You can have specific rules that do not override general rules. D&D is underspecified in the extreme--the ruleset (general and specific together) only covers a vanishing fraction of the game surface. That does not mean that anything outside that is impossible. Or that it is possible. Anything outside that is of indefinite possibility. Because the most general rule of D&D is that the DM decides how to resolve things, possibly referencing rules to do so.

Specific is just specific. General is general. You can't reason from specific to general. And no, D&D is not (nor was even in 4e) written like a MtG card. The styles are completely different. Losing a limb may be possible. Or it may not be. That's entirely unspecified by the rules. But if it does occur (and the DMG gives some variants for making it possible), regeneration would cover it. That does not imply that it's always possible. That's a logical error of the highest magnitude, unsupported by anything in the text or in any reasonable reading. And is the source of 90% of all arguments about rules and absurd readings.

In effect, when asked "can limb loss occur", the rules say neither yes nor no. They say "dunno, ask your DM." And whatever the DM decides is the rule for that case, at that table. But not for any other case, or for any other table. That's the essence of rulings over rules.

[qube]

The Observant feat allows a character to read lips, therefore, characters without the Observant feat cannot read lips.It's a Proving too much fallacy - an argument that results in an overly generalized conclusion

The key example is "drinking alcohol is bad because in some instances it leads to bad situations.

It's marked by an overgeneralisaion (the existance of an ability is an indication (though not proof) that you can only do the thing with said ability) and easily defeatable by using the logic to prove something absured (ex. Segev's Mermaid example would mean nobody else breath air)

[Vahnavoi]

Specific trumps general does not imply (as I've already stated) that specific implies general. That's utterly not part of the system. And it has to be to make your argument meaningful. All it means is that IF
a) there is a specific rule and a general rule covering the same condition
b) and they are in conflict
THEN the specific one wins.

Both must be true. But you can have general rules that are not overriden by any specific rules. You can have specific rules that do not override general rules. D&D is underspecified in the extreme--the ruleset (general and specific together) only covers a vanishing fraction of the game surface. That does not mean that anything outside that is impossible. Or that it is possible. Anything outside that is of indefinite possibility. Because the most general rule of D&D is that the DM decides how to resolve things, possibly referencing rules to do so.

Specific is just specific. General is general. You can't reason from specific to general. And no, D&D is not (nor was even in 4e) written like a MtG card. The styles are completely different. Losing a limb may be possible. Or it may not be. That's entirely unspecified by the rules. But if it does occur (and the DMG gives some variants for making it possible), regeneration would cover it. That does not imply that it's always possible. That's a logical error of the highest magnitude, unsupported by anything in the text or in any reasonable reading. And is the source of 90% of all arguments about rules and absurd readings.

In effect, when asked "can limb loss occur", the rules say neither yes nor no. They say "dunno, ask your DM." And whatever the DM decides is the rule for that case, at that table. But not for any other case, or for any other table. That's the essence of rulings over rules.

Specific rules don't have to imply general rules. They, however, can, and do, based on their construction, which is what the "air-breathing mermaid problem" and "exception proves the rule" are all about. You give WotC folks too much credit if you think they never stumble upon such constructions. The reason why these kinds of arguments happen in context of character abilities, such feats or class features, is because those are constructed as exceptional - they are plainly intented as something people without the ability cannot do. This is visible, for example, in construction of feats in d20 system reference document: each feat has "normal" to remind how the game process works outside the exception granted by the feat, followed by the actual exception and benefit. It should be easy to see how some clueless mofo can use this formulation to define a previously undefined general rule, such as establishing you cannot do something simple without a feat.

The underspecified status of the game as a whole remains irrelevant. In absence of other rules and principles, people draw conclusions based on rules that are present. If the only player-facing method for doing a thing is given in format of exceptional ability, it is perfectly reasonable for them to assume the general rule is that it cannot be done without exceptional ability.

As for M:tG's influence on D&D... some of the staff (starting with Monte Cook during 3rd edition era) have outright admitted the influence. The culprit has admitted the crime, and you are still arguing about style. :smalltongue:

[qube]

The underspecified status of the game as a whole remains irrelevant. In absence of other rules and principles, people draw conclusions based on rules that are present. If the only player-facing method for doing a thing is given in format of exceptional ability, it is perfectly reasonable for them to assume the general rule is that it cannot be done without exceptional ability.Quite true - but this inherently makes it fallicious.

The Observent feat notes "If you can see a creature's mouth while it is speaking a language you understand, you can interpret what it's saying by reading its lips.". It would be a reasonable assumption of anyone reading this, that this implies that without an ability, you can't do this (or at least not as an automatic success).

This is because we assume the Observent feat
(a) should be worth the investment of a feat and
(b) that it won't give something the players don't already have.

Yet, as underlined, those things are assumptions. Just like we saw with the grappler feat, it's always possible a mistake slips in in writing an ability.

Depending on context, I would consider it strong evidence though. Especially as most discussions are about RAW.


If you don't have the observent feat, you can't read lips*

* : unless your DM decides you can**

** : which is true for anything, so not a valid counter argument

[Frogreaver]

I wish there was a named fallacy for seeing a fallacy where there isn’t one.

[PhoenixPhyre]

I wish there was a named fallacy for seeing a fallacy where there isn’t one.

This isn't quite that, but there's the fallacy fallacy--just because an argument uses a fallacy doesn't mean the conclusion is invalid, merely that the logic can't get you there from those premises.

But I agree. Most of what people talk about online as "fallacies" are just people trying to weaponize language so they can claim other people are wrong without having to actually make an argument themselves. It's an insult word, designed to shut down discussion. In part because none of us are performing acts of formal logic, which is the only place fallacies really have bite. Informal logic isn't nearly as susceptible to them, at the cost of being much less precise and definitive. And natural language generally only uses (or uses by default) informal logic. Or no logic at all--most of what we discuss is purely subjective taste.

[Thunderous Mojo]

I wish there was a named fallacy for seeing a fallacy where there isn’t one.

Fallattio, perhaps?🃏

[CapnWildefyr]

This isn't quite that, but there's the fallacy fallacy--just because an argument uses a fallacy doesn't mean the conclusion is invalid, merely that the logic can't get you there from those premises.

But I agree. Most of what people talk about online as "fallacies" are just people trying to weaponize language so they can claim other people are wrong without having to actually make an argument themselves. It's an insult word, designed to shut down discussion. In part because none of us are performing acts of formal logic, which is the only place fallacies really have bite. Informal logic isn't nearly as susceptible to them, at the cost of being much less precise and definitive. And natural language generally only uses (or uses by default) informal logic. Or no logic at all--most of what we discuss is purely subjective taste.

Yup.

I think that it helps to look at these cases, when they arise, not just as "there's a feat for it so you can/cannot replicate it any other way" but also in terms of nature vs nurture. That is, mermaids breathing air is a biological thing (nature). If there is a new feat for breathing air, it's a rules change, and certainly does mean that mermaids no longer can breathe air without it (if you use feats). Just like other rules changes for monster stat blocks, or for spell descriptions. OTOH, something like reading lips is a learned skill (nurture). One way to get that skill is through the feat, but a DM can allow other ways to learn it, and can furthermore allow varying degrees of success and difficulty. It might be easier to read lips to figure out if someone is laughing, or calling the guards, and harder to actually follow a conversation about how the new safe word for the iron golems on the third floor is now "izzy iizy bop." Now, if the DM says "you must have the observant feat to read lips," so be it, live with it for the moment, and talk about it before next session. Not a logical fallacy, it's a ruling.

Now, I am not saying the we can't jump to conclusions, over generalize, or whatever, only that -- like everything else in a game that needs a DM/GM to arbitrate -- you need to, you know, arbitrate, and that such arbitration is not in of itself a logical fallacy.

[Telok]

Feels like one of those negative space illusions like the https://en.m.wikipedia.org/wiki/Illusory_contours triangle but with a rule set instead of pictures. D&D has a set of basic rules telling you what you can do and a set of exceptions rules telling you if you can do something beyond or breaking the basic rules. So when you hit a rule that looks like an exception rule (observant feat, assassin fake ID) the players are expecting it to be an exception to a basic rule, because thats how current D&D is perceived to be built by the casual/non-developer users.

Someone who draws or studies these sorts pictures sets may know that its an illusion right off and remember the individual bits. Casual untrained people who get spammed with a lot of these, put in a pressure situation, and asked about it will say there's a triangle. Likewise people who write or heavily analyze rule sets will recall the individual rules and how they don't say something even if its implied. But casual users under pressure of DMing will recall the pattern and think there's a rule denying something.

Just yesterday had a DM, experienced & veteran & good, he & the rest of us couldn't recall off the tops of our heads in this edition had a shift/5 foot step/cautious move/reposition thing that let you move a short distance without provoking opportunity attacks and still can attack. The DM absolutely remembered the npcs could do it (turns out they flew & had flyby but everyone kept mixing up which tokens represented the winged ones), but all of us have played so many games with that sort of rule and 5e has stuff like that sort of rule which caused us confusion. Under time pressure we couldn't not see the triangle.

[Psyren]

There's actually three things that may be going on here at once:

1) Inverse error / denying the antecedent
2) Specific trumps general
3) Exception proves the rule

Only the first is strictly a fallacy, the other two are overarching principles for rule interpretation. Bad application of the latter two can directly lead to the first, though.

Let's look at these in order:

1) Inverse error: "A thief can sneak attack. I am not a thief. Therefore I can't sneak attack." Both premises are correct, but they are not sufficient for the conclusion, because there might be a way to sneak attack that doesn't require being a thief.

2) Specific trumps general: there is a hierarchy of rules. There are basic rules and special rules and when the two are in conflict, the special rules are followed over the basic ones. So if basic rules say a surprise attack gets you +2 to hit, and rules specific to thieves say a surprise attack counts as a sneak attack, when a thief makes a surprise attack, you adhere to rules of sneak attacks.

3) Exception proves the rules: special exceptions imply general rules are followed outside those exception. So if rules say thief's surprise attack counts as a sneak attack, this implies other attacks don't count as sneak attacks.

Out of these, 2) and 3) put together create the "air-breathing mermaid problem". Said problem is not a fallacy. It is an issue of bad game design. Specifically: a rule set was constructed following 2). It was silent on whether mermaids could breathe air. Since under basic rules all characters could breathe air, the straight-forward interpretation was that mermaids could breathe air too. Then some clueless mofo added in a special rule, in the format of a feat (etc.), that says it allows mermaids to breathe air. Since specific trumps general, addition of such a rule in such a format is only necessary if the general rule is that mermaids cannot breathe air. This leads, via direct application of 3), to the implication that mermaids without the feat cannot breathe air, reversing previous rule interpretation.

So. Back to 1). In D&D, class features and such are typically presented to players in a format that implicitly or explicitly follows 2). They are presented as special permissions to do something others cannot. They typically do no give any constructive formulation for achieving the same things in other ways. This, via application of 3), leads to interpretation that such things cannot be done in absence of such special permission. It is up to the game master to show where in the basic rules alternate methods are allowed to achieve the same effects.

Agreed with this breakdown and the reason why inverse errors pop up so often in D&D.

I would tweak your last sentence though - rather than it being up to the game master, I'd argue that most often it's up to the player. The game master doesn't need a general rule to permit or even deny an alternate means of accomplishing something, rather it is the player who needs one in order to plead their case (or gain a benefit from the feature they invested in.)

[BoutsofInsanity]

It's one of those things about D&D I guess that there isn't really a fallacy specific to it.

It falls into that category that is one of those rules questions that will separate good 5e DM's from bad 5e Dm's. Specifically for this edition obviously, because the ambiguity is built into the system, and other systems not requiring ambiguity are better served in the opposite direction.

As is the case for a lot of D&D 5e it looks like this one is "Ask your Dm."

Which is a shame, because I think the beauty of 5e is the fact that there are so many different ways to get to the same solution and nearly all of them are valid. In this instance I think the PHB or DMG having a page on rulings versus rules, and providing a little bit of guidance on intended design wouldn't be a bad idea.

A wizard polymorphs into a giant ape and jumps up to the Dragon hanging off the ceiling to pull the dragon down. How should that be ruled?

Go by carry weight and then estimate the weight of the giant ape
Opposed strength athletics checks, shove (Pull) versus the dragons
The DM chooses a DC based on difficulty
The Dm sets a DC based on the Dragon's Strength Score

[KorvinStarmast]

For the OP: it's not a fallacy.

Narrowmindedness. It came into RPGs with the "video gamer" set who were used to rules and limitations. {snip} One might even question WHO might be better at it, the Assassin or the Bard? Indeed.

I think it's less a fallacy and more a failure of... imagination, maybe? I don't want to be too harsh. You nailed that dive.

The game designers start with the assumption that most people cannot read lips. IRL, most people can't read lips, so it's reasonable to assume that PCs cannot do so unless they have the ability granted by a specific feature like the Observant feat. So far so good.

The Assassin feature seems like a problem, though: making it a class feature strongly implies that the designers don't think that people should be able to do this without special training. Or you can apply the tool given to the DM, which is to apply disadvantage to the untrained/unspecialized attempt. (That was mentioned up thread a bit). That allows the option to anyone but allows for the Assassin being better than most at this thing.

"Any action can be attempted if it has not specifically been prohibited", combined with good old "game master as referee has final say over game matters". It makes for better game play IME.

The key word in the rogue assassin ability is "unfailingly". There is no chance of failure. A different character with proficiency with disguise, forgery etc can certainly attempt it but there will be one or more chance for it to fail and there may be risky steps involved such as stealing blank documents as the basis for a forgery. No roll required. :smallwink:

Sometimes the rules allow. Sometimes they forbid. Sometimes they are silent.
{snip details} This thread to me sounds more like a players attempt to force or persuade a dm to rule in his favor by falsely referring to what is rightfully the DMs ruling as a fallacy. Ya think? :smallwink:

Based on date, I presume this is about 5th edition, I don't own 5th edition books so I can't easily check. Yes, they ported it in from 4e in the text of the Basic Rules for 5e on page 5:

Specific Beats General
This book contains rules, especially in parts 2 and 3, that govern how the game plays. That said, many racial traits, class features, spells, magic items, monster abilities, and
other game elements break the general rules in some way, creating an exception to how the rest of the game works. Remember this: If a specific rule contradicts a general rule, the specific rule wins. Exceptions to the rules are often minor. For instance, many adventurers don’t have proficiency with longbows, but every wood elf does because of a racial trait. That trait creates a minor exception in the game. Other examples of rule-breaking are more conspicuous. For instance, an adventurer can’t normally pass through walls, but some spells make that possible. Magic accounts for most of the major exceptions to the rules.

It gives ability to regenerate limbs, in a system that does not have rules for losing limbs anywhere. There is an optional DMG rule on losing limbs, though ... :smallcool:

Most of what people talk about online as "fallacies" are just people trying to weaponize language so they can claim other people are wrong without having to actually make an argument themselves. This.

Fallattio, perhaps?🃏 Congratulations, you just won the thread. Applause

[MoiMagnus]

So I see this a lot and I don't know what this fallacy in game design is called.

Where people assume that because some other game mechanic is written down for a specific feat or class, it precludes anyone else from being able to do said ability in some other way.

For a very imperfect example - The Assassin Rogue at level 9 can create an identity for themselves with 25 gold pieces and a weeks worth of downtime. This ability does not preclude someone else at the table for taking time themselves to use skill checks and such to create a false identity for themselves either.

Both can be true at once.

But someone people will argue that because the Assassin Rogue has that feature it precludes others from being able to do said ability because otherwise it devalues the class feature.

What is that called?

It's not a fallacy at all.
It's a belief about how game design should work, belief that you (and I) can disagree with.
But there is no leap of logic in the argument itself: it indeed devalues the class/feat features (or the other way around, making this ability exclusive to the class/feat increases its value).

And it's a question of opinion/belief if having exclusive abilities is worth the trade-off of restricting the other players.

Admittedly there might be a few fallacies depending on how they word their opinion:

There might be some over-interpretation of the designer's intention.
There might be some fallacy of presuppositions because of all the assumptions about the powerlevel of said class/feat features and the ideal powerlevel of those.


But IMO, it's not really a false dichotomy as much as it is a forced dichotomy. They're not that much saying that "there is no choice, either an ability is not governed by the rules, or the ability is explicitly granted by the rules to certain characters and no one else get them" (which would be a false dichotomy), but more saying "there should be no choice, there should not be any in-between, either an ability is not governed by the rules or it is granted to certain characters and no one else get them" (which is saying that this dichotomy is in their mind better for the game).

[Segev]

It's not a fallacy at all.
It's a belief about how game design should work, belief that you (and I) can disagree with.
But there is no leap of logic in the argument itself: it indeed devalues the class/feat features (or the other way around, making this ability exclusive to the class/feat increases its value).

And it's a question of opinion/belief if having exclusive abilities is worth the trade-off of restricting the other players.

Admittedly there might be a few fallacies depending on how they word their opinion:

There might be some over-interpretation of the designer's intention.
There might be some fallacy of presuppositions because of all the assumptions about the powerlevel of said class/feat features and the ideal powerlevel of those.


But IMO, it's not really a false dichotomy as much as it is a forced dichotomy. They're not that much saying that "there is no choice, either an ability is not governed by the rules, or the ability is explicitly granted by the rules to certain characters and no one else get them" (which would be a false dichotomy), but more saying "there should be no choice, there should not be any in-between, either an ability is not governed by the rules or it is granted to certain characters and no one else get them" (which is saying that this dichotomy is in their mind better for the game).

In the vein of "it devalues the feature," the reason that people tend to assume, "Features says I can do X if I have it. Nowhere else in the system is X mentioned. Therefore, if I do not have Feature, I cannot do X," is very much related to this.

As a silly example, if there was a subclass of Wizard called "the Walking Wizard," and it gave, at 2nd level, a feature called, "Walk and Talk," which permits the wizard to use his action to cast a spell even on a turn where he also moves up to his movement speed, that would be a feature, sure. It's a totally worthless feature, since anybody who can cast spells can do that, because the rules clearly say they can, but it's a feature.

Now, take away, "the rules clearly say they can," and we might suddenly have people asking, "Wait, if it takes the Walking Wizard using Walk and Talk to be able to cast a spell AND move up to his movement speed in the same turn, does that mean most spellcasters have to not move in order to cast spells?" And it's a very reasonable question. Why would a feature exist if it does literally nothing?

Now, with Observant, one might argue that it obviates the need for any rolls to successfully read the lips. But what rolls would normally be needed? Wisdom(Perception) to see the lips moving? That's already required if there's question about the Observant character being able to see them. Intelligence(Investigation), perhaps? So now they need one more roll? But how hard is it? THere's nothing in the RAW that tells you what constitutes an Easy Investigation Check, only what the DC is if it happens to be Easy. Is reading lips Easy? Hard? Nigh Impossible? If there were no Observant feat, then DMs may feel obliged to come up with an answer to this, because lip reading IS a thing some people can do. But with the Observant feat and utter silence anywhere else on how to achieve lip reading, isn't it very reasonable to assume that only the Observant can read lips? Why would you give a feature for free to somebody who hasn't invested in it when there's a clear cost to gain that feature?

Monks have a class feature to run up walls. Should you permit any PC to make a Dexterity(Acrobatics) check to do the same thing, rather than requiring them to use the general climbing rules?

Barbarians on the Path of the Beast have rules at 6th level to permit them to roll a Strength(Athletics) check and add the result in feat to their jumping distance while raging. The RAW for jumping mention that the DM will have you roll Strength(Athletics) to see if you can jump further than your Strength score in feet, but give no guidance on what that DC should be, or how far a given result should send you. Now that we have a subclass feature that gives the result on the roll as the extra distance in feet, does that mean that that's not what literally anybody can do? Or does it mean that that's a non-feature?