Plato distinguishes knowledge in terms of what the knowledge is of. And Plato would not honor the true belief about the name of the capital of E. with the honorific, "know".

Yes, that is right. People are very certain of mathematics, because they are used to the type of a priori reasoning.



I don ` t care if you can ` t add numbers. Mathematics as i know it are about theorems, and their proves. People are very certain of the theorems in mathematics, because their truth can be deduced by axioms, and accepted rules.

And do not you think Plato has a point.
that Quinto is the capital of E. is a rather trivial and self defining form of knowledge of a different character than say.
Newton's law of gravity or Einstein's general relativity?

People feel very certain, and believe they are certain, but that doesn't make them certain. And they cannot be certain, since they can be mistaken. And we know that they can be mistaken because, like me, they make mistakes when they add numbers, and even when they try to perform deductions. Or are you telling me that mathematicians never make mistakes when performing deductions?

kennethamy, are you certain of anything? I mean is there any time when it is proper to use that word. I mean when you are certain it is proper to use the word "certain".

I am a fallibilist, so I doubt whether anything I know is certain. But, is it ever proper to use the term "certain". Sure. When you believe that your justification for what you believe you know is so strong, that to say that you were not certain of what you know would be misleading to others.

We should distinguish carefully between whether we are justified in claiming that P is true, from whether P is justified for us. "I am in a coma" may be justified for me when I am in a coma. But I can never be justified in claiming I am in a coma, since anyone who is in a coma cannot claim anything at all. Claiming that P is true is one thing, but P being true is a different thing.

You have it all confused. Certainty is a psychological state that an agent has. Agent S is certain of a particular option if, and only if S thinks the option has a high probability of being true. This does not follow that option could not possibility be false. As you say, knowledge does not demand certain, but neither does certainty implies knowledge. You can be certain of P, even if P is false.

Yes, you are right. My use of "certain" is quasi-technical. I mean it the way philosophers have used it (or have talked about it). I mean what might be called "Cartesian certainty", not the ordinary use of the term, "certain" which, as you correctly point out does not imply truth. The philosophical use of the term (Cartesian Certainty) does imply truth, and it implies the impossibility (and not just the inactuality) of error. Cartesian certainty is not a psychological state, but yes, ordinary use certainty is.

Should we ever say "P is true." Or to be safe should we say instead "I claim that P is true." But then we'd have to say "I claim that I claim that P is true." and so on. I suppose it is obvious that we are claiming something so it need not be said.

But if our own statements and the statements of others are always implicitly bracketed off as mere "claims" from where do we get our concept of certainty?

What is the difference between Cartesian certainty and psychological-state-certainty?

Of course we should say that P is true, whenever we believe that P is true. The philosopher, Harry Pritchard, resolved never to promise anything because no person can absolutely guarantee that he will keep his promises. Something may always happen that will prevent it. (He may die before he can, for instance). So, Pritchard would never say the words, "I promise to do so-and-so". Instead he said, "I fully intend to do so-and-so". Fine. But it wasn't long before his friends knew about Pritchard's resolution. So, whenever he said, "I fully intend to do so-and-so", his friends would say,"Oh, that's just old Harry being careful. We know what he means. He means he promises". It is hard not to speak ordinary language. The same goes (ceterus paribus) for saying, "I am certain that so-and-so".

What I said. If you are cartesianly certain, then it is impossible for you to be mistaken. You know infallibly (in the instance). But if you are psychologically certain it is possible for you to be mistaken. You just believe it is impossible (or maybe you feel sure you are not mistaken).

Yes, you are right. My use of "certain" is quasi-technical. I mean it the way philosophers have used it (or have talked about it). I mean what might be called "Cartesian certainty", not the ordinary use of the term, "certain" which, as you correctly point out does not imply truth. The philosophical use of the term (Cartesian Certainty) does imply truth, and it implies the impossibility (and not just the inactuality) of error. Cartesian certainty is not a psychological state, but yes, ordinary use certainty is.

Certainty is often explicated in terms of indubitability. This has been done in a variety of ways. One prominent account of certainty is suggested by Descartes's presentation of his famous Archimedean point, the cogito (I am thinking, therefore I exist). In the Second Meditation, Descartes reviews the extensive doubts of the First Meditation before saying that even if "there is a deceiver of supreme power and cunning who is deliberately and constantly deceiving me," still "he will never bring it about that I am nothing so long as I am something" (PW 2, p. 17). Descartes then concludes that the proposition that he himself exists is true whenever he considers it. It is often thought that the cogito has a unique epistemic status in virtue of its ability to resist even the "hyperbolic" doubts raised in the First Meditation (see Markie 1992 and Broughton 2002). However, even if Descartes took this view of the certainty of the cogito, he did not accept the general claim that certainty is grounded in indubitability.

I tend to agree having broken a few promises and not all of them due to a lack of will power. Didn't Sartre have a similar argument against getting married? Yet I think Sartre would also say, one always has a choice whether to break a promise or not. Hmmm... maybe Sartre's argument against marriage is different from Pritchards.

Does Cartesian certainty ever occur in real life. If not, how do we know it exists? Do we have any evidence for it?

Are you saying certainty implies truth? This is completely ridiculous. It is probable the most ridiculous thing i read from you.

Some (Descartes for example) held that we can be Cartesianly certain that we exist. And that I exist is probably the best candidate for Cartesian certainty. If not, then like the unicorn, it is not instantiated.

You seem more certain of the existence of psychological-state-certainty than you are of the existence of Cartesian certainty...or perhaps equally uncertain of both?

I just said "more certain" which suggests that there are degrees of certainty. One can be more certain of one thing than of another. Or is this just an mistake of the common parlance use of the word "certain" and the fact that we can add the word "more" before any adjective or adverb. Is this mistake avoided when we use the word "certain" in its philosophical sense properly?

Yes, of course. We all know that we sometimes feel certain about some things. We certainly feel certain that we exist. There are degrees of psychological certainty, certainly. But not of philosophical certainty. That is either on or off.

Which cause is the strongest, you think? I'm inclined to believe the modal fallacy because of previous failure to explain that to people even given lengthy discussion.

But surely this is a function of the way you define philosophy. This particular view is derived from the Aristotlean laws of thought, isn't it? Something either being A or Not A, and never both or neither? So this is, again, amounts to the assertion that a thing either exists or doesn't exist, either we know something, or we don't.

---------- Post added 04-28-2010 at 06:43 PM ----------

In saying this, I highlighting the distinction you make between 'psychological' and 'philosophical' certainty. I would think that it would be absurd to ask yourself, while you're in pain 'am I really in pain?' The same can be said, as you observe, for existence; you can't reasonably doubt that you exist, as Descartes said. But it seems 'propositions about states of affairs' or 'knowledge of externals' is a different matter.

Look, this is all really quite simple. People (like me) don't feel comfortable saying that they know something that the truth value of which is actually false. If you say, 'I know X' and then X is shown to be false, one doesn't say that he knew it, or still knows it. He says he was wrong when he said 'I know X'.