Would an angel know if a sphinx were lying?

[No brains]

It's time for another one of those immoveable object versus unstoppable force questions that isn't clearly cut by the rules.

Angels possess Divine Awareness, which lets them know if they hear a lie. Sphinxes have Inscrutable, which states that a Sphinx is immune to any effect that would sense its emotions or read its thoughts, as well as any divination spell that it refuses. Wisdom (Insight) checks made to ascertain the Sphinx's intentions or sincerity have disadvantage.

Which of these abilities trump the other, and how would you explain why?

First, my gut instinct is that Angels (Planetars and Solars) would know if a Sphinx were lying. The Angel's power doesn't have as many facets and exceptions as the Sphinx's. You can't give disadvantage to an auto-win.

But I still think it's worthwhile for a DM to think of whys, even if they won't tell their players their reasoning. It can be an exercise in thinking about the order of their settings.

One way to think about it is that the Angels don't experience truth the way other creatures like mortal PCs do. They just know if words said don't reflect reality. This means that the Angel never has to read the Sphinx's mind or ascertain the Sphinx's sincerity, it can just take the cosmic way around deception and understand if there is a lack of truth to something said.

Another way to think about it is to go by creature strength. You can do this through CR as a shortcut or do more granular work with skills and saves, but sometimes one creature can 'pull rank' on another to see if its power trumps another. So a CR 16 Planetar might intuitively know that a CR 11 Gynosphinx is lying, but a CR 17 Androsphinx might be able to lock a Planetar out- if they can't get the help of a CR 20+ Solar. Literal rank might indeed by part of why this works, especially in this case, since the same god may have empowered different creatures to different degrees and trusted them with different levels of clearance on their divine plans.

Another case to think about is what if a Sphinx needs to lie to an angel? Well Angels only know if they 'hear' a lie, so taken literally, a Sphinx may choose to deceive an Angel with non-auditory information. They could present answers as the visual effects of spells, or opt to speak to the Angel telepathically. Further, a Sphinx could appeal to other limitations to present the Angel with incomplete information whether or not it lies. It may present whatever answer it will give as its riddle game, to be punished with violence or banishment, as the ancient laws decree.

Hopefully this has provided some creative food for thought and can help enhance your worldbuilding experience. Or, you could just murderhobo both the Sphinx and Angel and then write your own truth with Wish. The answer no longer matters to me. Farewell!

[Hairfish]

I'd probably just rule that they cancel each other out and they have to make a contested Deception vs Insight roll.

[InvisibleBison]

The two abilities don't interact. Knowing that what a sphinx just said is a lie doesn't require an angel to sense its emotions or read its thoughts, and Divine Awareness isn't a divination spell.

[Psyren]

The angel wins as InvisibleBison stated. The sphinx's ability imposes disadvantage on insight checks to detect a lie - but the angel isn't making a check, it just automatically succeeds at detecting a lie if it hears one.

With that said, just because you know what you've heard is a lie, doesn't mean that the creature who lied to you is under any obligation to tell you the truth, nor does it mean you know what the truth is.

Lastly, note that not all angels have this ability. Planetars and Solars do, but not Devas.

[Amechra]

Angels win here.

As for why... one idea is that Angels effectively auto-translate everything they hear into Celestial (and anything they say out of Celestial — that's the real reason that the speak "all languages"). And, in Celestial, lying is really obvious thanks to grammatical traits — for example, it has strong evidentiality marking, which the translation magic helpfully fills in with 100% accuracy.

[Mastikator]

The angel knows that the sphinx is lying, but the angel has no clue why the sphinx is lying. The sphinx is impossible to read, anything it says is fair game.

[Reynaert]

It does really depend on your definition of 'Lie', though.

If somebody firmly believes something, and then speaks that belief, but it turns out to be false, was that a lie?

[Unoriginal]

As said by others:

-The Angel detects lies 100% of the time

-The Sphinx's ability makes it harder to detect their lies, but not impossible.

Therefore if the Sphinx just lies the Angel would know.

That being said, a Sphinx knowingly talking with an Angel would likely be smart enough to avoid straight up lies, preferring riddles and exact-words and I-say-one-thing-and-let-you-fill-up-the-the-blanks-to-my-advantage tactics, against whom the Angel would have to use WIS (Insight) with disadvantage.

[Silly Name]

It does really depend on your definition of 'Lie', though.

If somebody firmly believes something, and then speaks that belief, but it turns out to be false, was that a lie?

Lying necessitates intentionality. Being misguided is not the same as lying.

I've never met anyone who would earnestly argue you can speak a lie without knowing it.

[kazaryu]

That being said, a Sphinx knowingly talking with an Angel would likely be smart enough to avoid straight up lies, preferring riddles and exact-words and I-say-one-thing-and-let-you-fill-up-the-the-blanks-to-my-advantage tactics, against whom the Angel would have to use WIS (Insight) with disadvantage.

i actually had a situation like this come up. it wasn't a sphinx, but a primordial. they were tryna convince the angel the they meant no harm and that a person was safe to be left with them. trying to argue "you know im not lying, you'd know". angel was like "yeah, of course you're not dumb enough to blatantly lie." i think the exact phrasing was like "even mortals know how to deceive while speaking truths, they learned it from the fae". good times.

[KorvinStarmast]

It does really depend on your definition of 'Lie', though.

No, it doesn't.

Lying necessitates intentionality. Being misguided is not the same as lying.

Correct.

For the OP: these are both monsters/NPCs controlled by the DM.
The DM rules on how it all works out if you don't care for the (IMO correct) answer that the angel knows that there is a lie.

The DM calls for a check, or not - since these are both NPC/Monsters under DM control, making a ruling is as good of a choice as any.

[Unoriginal]

The DM calls for a check, or not - since these are both NPC/Monsters under DM control, making a ruling is as good of a choice as any.

Worth noting that a WIS (Insight) check isn't just a "are they lying?" check, but a "what are they doing/thinking?" check.

You're right it's DM's call if there is check, of course.

[Damon_Tor]

I expect that a sphinx would be intelligent enough to know that an angel will know a lie when they hear it and will act accordingly.

[KorvinStarmast]

I expect that a sphinx would be intelligent enough to know that an angel will know a lie when they hear it and will act accordingly.

Is it a History or a Religion check to know that?

[brainface]

The angel knows that the sphinx is lying, but the angel has no clue why the sphinx is lying. The sphinx is impossible to read, anything it says is fair game.

I'd have a villain sphinx intermix one lie within a factual statement the angel really needed to act upon, just to be a jerk.

[Damon_Tor]

I'd have a villain sphinx intermix one lie within a factual statement the angel really needed to act upon, just to be a jerk.

That's definitely one solution: if the angel reads everything you say as a lie, even if what you're saying is mostly true, then the lie detection power may as well not exist due to "false positives". Great idea.

[Zuras]

That’s actually an interesting metaphysical question. I’d say that since angels are connected to actual capital t Truth, you can’t just launder a lie through a credulous dupe either.

Very reliant on the actual metaphysics of your campaign, though. I love the idea of angels hearing everything in celestial like a Star Trek universal translator except lies, which come through in the original language with celestial subtitles.

[Unoriginal]

I'd have a villain sphinx intermix one lie within a factual statement the angel really needed to act upon, just to be a jerk.

Pretty sure the angel would just detect the one lie as the lie and know the rest is not a lie.

That’s actually an interesting metaphysical question. I’d say that since angels are connected to actual capital t Truth, you can’t just launder a lie through a credulous dupe either.

A lie is relative to the person who says it.

The angel can't detect when people are factually wrong, only when people are saying what they know and believe is a falsehood.

[greenstone]

In the cosmology of my games:

Gods oversee the world. They are gardeners or caretakers (or maybe sysadmins) for the Material plane(s). As part of this, they have perception of the world far above the inhabitants of the world.

Some Celestials (angels, demons, devils, solars, planetars, devas, whatever you call them) are servants of gods. Those servants are given some of the power of the gods.

The ability to tell a lie is one of these gifts. A solar can tell truth from lies because they can see the actual workings of the Material world behind the scenes; they are not limited by the in-world perceptions of sight and sound.

A sphinx, despite all its power, is still a creature that lives in the Material world and is limited by the rules of that world.

Thus the solar's ability trumps the sphinx's ability.

Another way of thinking about it is watching a play while reading the script. A celestial sees an actor on stage say "I didn't betray the duke!" but also reads the script "Actor (lying): I didn't betray the duke!"

[Arkhios]

Angels win here.

As for why... one idea is that Angels effectively auto-translate everything they hear into Celestial (and anything they say out of Celestial — that's the real reason that the speak "all languages"). And, in Celestial, lying is really obvious thanks to grammatical traits — for example, it has strong evidentiality marking, which the translation magic helpfully fills in with 100% accuracy.

I'm curious, is this Angels effectively auto-translating everything, or the "knowledge" of the nature of Celestial or its grammatical traits from somewhere within the rules or something of your own cooking. Not that it isn't flavorful or cool, just that it isn't immediately obvious where you took that info from.

[JLandan]

It does really depend on your definition of 'Lie', though.

If somebody firmly believes something, and then speaks that belief, but it turns out to be false, was that a lie?

Unless the sphinx states that it is his belief and not a known fact, it is a lie. Stating that something you believe is truth is a lie. You have to know for a fact that something is true to present it as the truth. A belief, no matter how firm, is still a belief and not a fact.

[Unoriginal]

Unless the sphinx states that it is his belief and not a known fact, it is a lie. Stating that something you believe is truth is a lie. You have to know for a fact that something is true to present it as the truth. A belief, no matter how firm, is still a belief and not a fact.

If someone asks you what time is it while you don't have a watch and you state "5 o'clock" based on what you can perceive, then you're not lying just because you don't add a "I believe" or "I guess". Similarly, if someone asks you for a friend of a friend's name, and you don't remember the name for sure, you're not lying when you say "Ian Chesterfield", even if his name is actually Brian Chesterfield and you don't precise "I'm not sure".

Same if you believe something to be a fact when it's not. If a lawyer believe someone is a murderer due to the evidence presented during the trial, but in reality the person was framed for the murder, the lawyer isn't lying if they say "this person is a murderer". Or if you believe what is considered at the time a scientific fact that will be be debunked by a new discovery next week, you're not a liar for stating that fact.

A fact is something that people believe in based on evidence, but it's still belief. Because


The only way the Sphinx would be lying in that situation would be if they're asked "are there evidences to confirm this?" and they said "yes" when there isn't.


Basically, there is a big difference between a statement being wrong and a statement being false.