Knowledge

[TigerHunter]

Why is the Knowledge skill trained only? The DC for 'really easy questions' is 10, 15 for 'basic questions'. Everything else is 20 to 30--generally impossible.
Identifying a specific creature is 10+HD.
Assuming for the purpose of this argument that you have no ranks in the skill and an int modifier of 0, that would mean that you would know half the 'really easy questions', such as what the name of the nearest village is. This is sensible. You would know one quarter of the 'basic questions', such as what type of political system you live in, or who the king is. 'Really tough questions' like what the physical properties of adamantine are, would require ranks in the skill--again, sensible, as only specialists would reasonably have knowledge of such things.
For identifying monsters, you would know half the low HD monsters--animals and normal humanoids, generally. As monsters got tougher (aka rarer) you would know fewer and fewer of them. Sensible.
With the current system, a person without ranks in knowledge (nature) can't even identify a rat.
So again, why is knowledge trained only?

[JellyPooga]

Can't you roll Knowledge untrained, but you can't get any information 'worth' a DC above 10 from the check? I'm sure there's something in the rules about that...it means that if you're untrained, you can know really basic stuff, but don't stand a chance of knowing anything more than rumour, hearsay and common knowledge (like what a rat is).

[RamrodTheWizard]

Technically, if you're untrained in a knowledge skill you cannot succeed on anything above DC 10.

[TigerHunter]

Can't you roll Knowledge untrained, but you can't get any information 'worth' a DC above 10 from the check? I'm sure there's something in the rules about that...it means that if you're untrained, you can know really basic stuff, but don't stand a chance of knowing anything more than rumour, hearsay and common knowledge (like what a rat is).

I've read through the description 5 times, and I don't see anything regarding that. Huh.
Nevermind then. Ignore me.

[Starbuck_II]

I've read through the description 5 times, and I don't see anything regarding that. Huh.
Nevermind then. Ignore me.

Though, you wouldn't know what the rat can do (like it can climb or swim or has scent).

[kjones]

Well, then there's the classic fallacy of Knowledge DC = 10 + HD, which makes NO SENSE.

"What's that creature?"
"It appears to be a blue morpho butterfly, also known as morpho menelaus, renowned for their consumption of rotten fruit and cannibalistic larvae."
"And what about that?"
"That looks like a... um... bear of some kind... possibly black, or brown."

[Draz74]

LoL, kjones, exactly!

But besides the idea that the Knowledge check DC guidelines for creatures are horribly messed up anyway, the Rat strikes me as an example of where the DM should just rule that the DC is lower than the standard "guideline" would suggest.

[Gavin Sage]

Knowledge being trained only is a good thought gone bad. It makes sense for realism, but makes for bad mechanics. Especially with all the categories. It shouldn't be simply a skill but something more developed. Something like the a Bard's Lore but for everyone.

[TheOOB]

It gets worse, it's possible to be able to tell everything about a wyrmling red dragon, all it's abilities, everything, and know nothing about it's great wyrm mother.

[Skjaldbakka]

Some of the new material being put out actually gives a chart of Knowledge DCs with the critter/organization/PrC in question. If they do another monster book, or a Big Book o'Monsters, I think they'll include Knowledge DC and type in the stat block(which would break away from the 10+HD garbage).

[nerulean]

Knowledge checks are one point where any DM should make heavy use of circumstance bonuses.

[Rad]

Well, then there's the classic fallacy of Knowledge DC = 10 + HD, which makes NO SENSE.

"What's that creature?"
"It appears to be a blue morpho butterfly, also known as morpho menelaus, renowned for their consumption of rotten fruit and cannibalistic larvae."
"And what about that?"
"That looks like a... um... bear of some kind... possibly black, or brown."

"And that Big thing with red scales and breathing fire?"
"Oh, I have absolutely no Idea!"

[Diggorian]

Ha. Since the sentence about monster knowldge DCs starts with "In general," I take my que to just ignore it.

Knowledge X has gotta be a hard skill to write since really DC should raise with the rarity of the creature, not difficulty, but rarity is up to the DM given it's his/her world.

And as Nerulean points out, circumstance is important.

[horseboy]

Well, it's crazy, but not that far fetched. A lot of the talk radio stations in B'more like to send people down to DC and ask the locals questions like: "Who's the Vice President" and they can't answer it. They live a stone's throw away, surrounded by the US Federal Government and don't know. They'll go to the Lincoln memorial and ask people looking at the sign who is the guy a statue of and they still don't know. Then you've got that Jay Leno segment where he basically does the same thing, asking where they get chocolate milk from. There's a good element of randomness in what people do and don't know.

[Fax Celestis]

I don't use 10+HD, I use 5+CR.

[Yuki Akuma]

I don't use 10+HD, I use 5+CR.

Good for you.

[Fax Celestis]

Good for you.

A creature's strength and rarity are usually related to it's CR (see also: great wyrms and the tarrasque) rather than its HD. Using CR makes more sense, but it's still not a very good measure.

[Yuki Akuma]

A creature's strength and rarity are usually related to it's CR (see also: great wyrms and the tarrasque) rather than its HD. Using CR makes more sense, but it's still not a very good measure.

You know, of course, that this means no one knows what a whale is, right?

It has exactly the same problems as using HD.

[Fax Celestis]

Yeah, I know. It's a poor substitute, but at least it functions a little better.

I have not yet been able to come up with a decent equation to calculate Knowledge DCs, despite many attempts.

[CthulhuM]

Admittedly, your average medieval peasant (or king, or scholar, for that matter) probably wouldn't know what a whale was. If they saw one they'd probably just think something along the lines of "ohcrapdon'tlettheseamonstereatme!"

Admittedly, though, this is likely more because whales are sea creatures too big to catch and eat than it is because they're rare.

In any event, it seems like knowledge checks are one of those things that can't really be handled mechanistically. The DCs for many knowledge checks should actually vary depending on a character's background anyway - someone who grew up in Sigil would be hard-pressed to not know what a tiefling was, even if he didn't have more than a couple ranks in knowledge:planes.

[Diggorian]

I dont think there can be a general equation for all circumstances. Arctic dwellers face a low DC for whales, desert folk get a low one for camels (even lower if domesticated).

DCs should be based maybe on type: animals and vermin on the low end; abberations and outsiders on the high end. Again, in an Underdark game that order maybe inversed.

Really it's for a DM to judge.

EDIT: *pulls a ninja star from his back* And, see above

[Ssiauhll]

Why use HD or CR for a monster knowledge? Rather it should be how common the creature is, which I admit maybe the same thing in the end. People should know about a dragon if it lives near by, they are big an scary word gets around.

DCs
Rats, orcs, maggots, dogs, are the types of things that a peasant would know about. Dragons, gods, camels and wales are things that the commoner would have hard about extensively but would have never seen. They would know the most obvious information but thats it.

Additionally there should also be some false information that is commonly regarded as correct even thought it is not. This is there the true scholars would shine.

[Fax Celestis]

The DCs for many knowledge checks should actually vary depending on a character's background anyway - someone who grew up in Sigil would be hard-pressed to not know what a tiefling was, even if he didn't have more than a couple ranks in knowledge:planes.

That's called a "circumstance bonus" and is actually recommended by the DMG for exactly that reason.

[MrNexx]

Yeah, I know. It's a poor substitute, but at least it functions a little better.

I have not yet been able to come up with a decent equation to calculate Knowledge DCs, despite many attempts.

Define how common they are for certain areas. Common (PC races, common animals, common humanoids) is DC 10. Uncommon is 15. Rare is DC 20. Unique is DC 30. Knowledge: Region provides a synergy bonus.

[Kurald Galain]

You know, of course, that this means no one knows what a whale is, right?

Well, you got to admit that on this Earth's middle ages, just about nobody knew what a narwhal was...

[horseboy]

Define how common they are for certain areas. Common (PC races, common animals, common humanoids) is DC 10. Uncommon is 15. Rare is DC 20. Unique is DC 30. Knowledge: Region provides a synergy bonus.

Survival and nature would be good synergies too.
"What is it?"
"I'm not sure the exact name, but it's good eatin'"

[bugsysservant]

Rather than giving circumstance bonuses, wouldn't it be more logical to just award three or four ranks of knowlege to every character unconditionally based on their background? Any more than that would require study, but four ranks could be a fair mechanical simulation of a character's background. The concept of a circumstance bonus is a bit absurd for knowlege checks in this context anyway. "You don't actually know anything about the place you grew up in, but you're going to get a bonus to the role because you grew up there"?

[Bassetking]

Well, you got to admit that on this Earth's middle ages, just about nobody knew what a narwhal was...

Sea Mermaid.... Unicorns! Mermaidicorns! Crap, did I just create another Elven Subrace?

[nerulean]

Rather than giving circumstance bonuses, wouldn't it be more logical to just award three or four ranks of knowlege to every character unconditionally based on their background? Any more than that would require study, but four ranks could be a fair mechanical simulation of a character's background. The concept of a circumstance bonus is a bit absurd for knowlege checks in this context anyway. "You don't actually know anything about the place you grew up in, but you're going to get a bonus to the role because you grew up there"?

Actually, circumstance bonuses make a lot more sense. Giving someone who grew up in a desert three free ranks in Knowledge (nature) might seem like a feasible way of letting him know the difference between a human and a camel, but don't forget that that would give him a bonus in identifying a shark or a nixie, which would be somewhat out of his area of expertise.

[Diggorian]

Well, you got to admit that on this Earth's middle ages, just about nobody knew what a narwhal was...

Except Eskimos and other people of the Arctic climes. All in the circumstance.