These three words do seem interchangeable, but they are not. A character can be Smart and Clever, but not Intelligent.

How would you define each of them in a RPG context?

Intelligent - Overarching cognitive capacity to reason literally and abstractly. I'd use this term as a "rational capacity indicator". It's much more formal than the other two. Intelligence to me is System 2 thinking (see below). It's slow and deliberative. It's where individuals weigh the pro's/con's of an observation or idea, and is the "muscle" that allows you to interrogate a concept slowly until you suss out the necessary analysis to draw an acceptable conclusion. Intelligence for me consists of acts of deliberate thought.

Clever - I associate as a sub-set of "Intelligence". It's closer to creativity, instinctual. I liken it to System 1 thinking, in reference to Daniel Kahneman's brilliant work on "Prospect Theory". It represents "fast" instinctive thought. Fueled by emotion and rationality, it allows for individuals to draw inferences from disparate facts and intuitions to formulate ideas *quickly*. The more clever you are - the more novel your problem-solving might be. This does not speak to accuracy, merely the capacity to attack problems with a wider set of disparate variables. "Clever" denotes more sub-conscious, instinctual cognitive problem solving than it does overt deliberative consideration. Probably much more than people realize.

Smart - Is a euphemism for "Intelligence" to me. I play Savage Worlds, it has Smarts. It's pretty much Intelligence/IQ/Cognition etc. all rolled into one. Used in the way you describe above, Clever<>Smart.

Quote from: Reckall;1118674These three words do seem interchangeable, but they are not. A character can be Smart and Clever, but not Intelligent.

How would you define each of them in a RPG context?

Step 1: See if the game you're playing already defines them (e.g., FFG's Star Wars uses Intellect and Cunning). If it does, the path of least resistance is to just go with the division it gives you.
Step 2: If you game does not define them, then consider whether it's even necessary to do so. Adding complication isn't bad if it improves the game, but it doesn't always do so.

As a hierarchy Clever (okay), Smart (better), Intelligent (best).

Intelligent = Abstract reasoning

Smart = Applied reasoning

Clever = Creative reasoning

What are we trying to measure? Education? Social savvy? Inventiveness? Cunning? Social manipulation? Tactical ability?

For me, the INT score or whatever its called in the particular game should reflect what its used for in that particular game.

For instance, in OD&D, high INT gave you the ability to speak more languages, so it was a stat about Memory and Knowledge. In Classic Traveller, INT is separate from EDUcation and beyond chargen, was really subjective to how it was used in actual play.

They may not be identical, but they tend to correlate.

Quote from: Reckall;1118674How would you define each of them in a RPG context?

I probably wouldn't. An RPG context is precisely where I would probably consolidate all those concepts into a single "mental speed" attribute (called "Awareness" in the system I'm currently designing) that handles all those functions. If I were to emphasize those functions I would probably still use a consolidated attribute as a base (probably "Intelligence"), then treat stuff like being "Clever" or "Smart" as "traits" (specific aspects) of that core attribute. The Cleverness trait would affect tasks dealing with mental agility and creativity--being witty and quick thinking when coming up with plans and stuff. While Smartness would affect tasks dealing with book learning and education. Intelligence itself (the core attribute) would affect all mental tasks, since the word "Intelligence" refers to overall mental aptitude and capacity for understanding facts or meanings, etc.

I usually don't go as far to break them into different stats, but I do sometimes describe the type of smarts a character has, when I think of it as having a certain "character".

But if do sort of think of such distinctions, so:

Intelligence - I might think of as the ability to understand and learn things through deliberate cognitive thinking in a thorough and organized way. Ideas, symbolic thinking, careful consideration, book learning, comprehending the fullness of situations, etc.

Cleverness - Subconscious perceptiveness. Creative problem solving, flashes of understanding, generation of new insightful ideas. Wit.

Smart - A term more likely to be used by different people in different ways. Often people mean a positive value judgement, as opposed to stupid. Or they mean what I would tend to call common sense, or a heavy tendency to check one's ideas before acting on them, or avoiding doing things that might have bad consequences. Some normative or conformist valuing people also may call people smart if they behave in normal ways they approve of. I would tend to not use smart as an attribute - I usually use it as a certain above-average level on an RPG's IQ scale, and the other meanings fall under the Common Sense trait.