David Hume believed that the question of whether animals were rational depended on whether animals could draw inferences, and to what extent they could.

Interesting Quote from Wiki, that touches upon my questions...

Quality of Rationality
...such an idealized form of rationality is best exemplified by computers, and not people. However, scholars may productively appeal to the idealization as a point of reference.

For me, rationality is not a separate thing than persuasion. It's a form of persuasion. A person can lay out their propositions and conclusions and still be doubted, for humans don't for the most part live on propositions and conclusions. You're quite welcome to your use of the word, of course, but for me it's too narrow of a use. I strive toward a more holistic understanding of human thought and behavior.

Whatever you like, bro. But it's pretty obvious what I meant.

(Is logos rationality. "Rational animal" in greek is "Zoon logikon" so I'm going to say close enough.)

Maybe. Now, if only we we knew what "logos" was.

Of the modes of persuasion furnished by the spoken word there are three kinds. The first kind depends on the personal character of the speaker [ethos]; the second on putting the audience into a certain frame of mind [pathos]; the third on the proof, or apparent proof, provided by the words of the speech itself [logos].

Logos, Ethos and Pathos were described by Aristotle in the Rhetoric (brackets mine).

Oh. Well now, that's settled. What else is there on the agenda?

The Aristotle quote I provided defined these terms by their roles within rhetoric. Does reason, rationality, logos have a life outside of rhetoric?

I imagine so. In mathematics, for instance, or in science.

Would you care to expand on that? Attempt to provide the mathematical definition of reason or rationality for example.

Didn't you ask whether "reason, rationality, logos have a life outside of rhetoric" ? My answer is, yes. In mathematics and science, and also elsewhere.

Would you care to expand on that? Attempt to provide the mathematical definition of reason or rationality for example.

Why should I have to do that? All I said is that reason is used in mathematics and in science. What has that to do with providing a mathematical definition of reason? If I said that reason is used in playing chess, would that mean there I had to give a chessic definition of reason?

You don't "have to" do anything but yes I would be very interested in reading your chess related definition of reason. Good idea. Give it a try.

There is no chessic definition of reason. Why should there be one? If I said that I try to use intelligence in playing chess, would you ask for a chessic definition of "intelligence"?

Sure, why not? What's your chess related (chessic) definition of intelligence? Or perhaps a better way to phrase it: What is reason within the context of a chess game? What are the qualities of an rational chess player? How can you tell that a chess player is being rational? What sort of things does that person do that make you say: "That person just isn't being rational?" Asking "What makes a rational chess player?" is very similar to asking the question: "What makes a good chess player?"

Another example would be the art of conversation (which, I would like to point out, is a very different sort of thing from a chess match.). What is reason within the context of a conversation? What are the qualities of a rational conversationalist? How can you tell that the person you are talking to is being rational? What sort of things does that person do that make you say: "that person just isn't being rational?" Asking "What makes a rational conversationalist?" is very similar to asking the question: "What makes a good conversationalist?"

Does logos have a life outside of rhetoric? If so then what is that life? If not then our task is to differentiate logos from ethos and pathos.

You think that for every activity in which intelligence is used, that there is a separate definition of "intelligence"? Why? You don't think that for every pair of shoes you buy, that there is a separate way in which you put on those shoes, do you? Getting back to "rationality", I think that Hume was on the right track when he held that rationality is the ability to draw inferences from the known to the unknown. And we use that ability in chess, as well as in philosophy, or in mathematics. "Logic" has been described as the science of inference, and that would explain the close connection between rationality and logic.

I would say "rational" is an adjective of praise. .

I would say "rational" is an adjective of praise. I believe rational comes from ratio, measure. Tautology is rare in logos (discourse made of words). Even then it's used to suggest something non-tautological, to imply an irreducibility. ("I am what I am" says God.). Math and formal logic seems to be tautological calculators, and they are extremely useful. But metaphor and trope, as essential feature of logos, do not compute tautologically. It's true that we can scan logos for a skeleton (there's a metaphor) that formal logic is fit to deal with, but much of the value of logos lies in its metaphores, tropes. I think we often apply the word "rational" to uses of metaphor that we find persuasive, useful, sane, sensible, etc. Of course "rational" is also applied to discourse's tautological skeleton.

Logos in its fullness demands a certain amount of personal interpretation. This differentiates it from math and formal logic which merely manipulate symbols according to rules.

I am quoting this because it seems apparent that certain readers did not get beyond the first sentence. Regards, recon.