Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!purdue!muttiah From: muttiah@cs.purdue.EDU (Ranjan Samuel Muttiah) Newsgroups: comp.ai Subject: Re: Recursive Searles, or what? Keywords: understanding Message-ID: <9172@medusa.cs.purdue.edu> Date: 5 Jan 90 22:03:34 GMT References: <12679@phoenix.Princeton.EDU> <12702@phoenix.Princeton.EDU> <7661@sdcsvax.UCSD.Edu> <9170@medusa.cs.purdue.edu> Sender: news@cs.purdue.EDU Reply-To: muttiah@cs.purdue.edu (Ranjan Samuel Muttiah) Organization: Department of Computer Science, Purdue University Lines: 107 -- In article <9170@medusa.cs.purdue.edu> muttiah@cs.purdue.edu (Ranjan Samuel Muttiah) writes: >Gottfried Wilhelm Leibniz wrote a letter to Hobbes in the form >of a dialogue. (It is presumed that that A is really Hobbes). >It was written in 1677 when Leibniz was just 24 years old! ^ X- should be 1670. --- On popular demand the dialogue continues: I am very happy to see that a brand new book is available on some of his essays, including this dialogue. G.W. Leibniz. Philosophical Essays Translated by: Roger Ariew Daniel Garber Hackett Publishing Company (1989) ------------------------------------------------------------------ A. But we should try for a reconciliation. Do you think that all of the thoughts there can be are actually formed ? Or, to speak more clearly, do you think that all propositions are being thought ? B. I don't think so. A. Therefore, you see that truth pertains to propositions or to thoughts, but to propositions or thoughts that are possible, so that, at very least, we can be certain that if anyone were to think in this way or in its opposite, his thought would be true or false. B. You seem nicely to have rescued us from that slippery place. A. But since there must be reason why a given thought is going to be true or false, where, I ask, shall we look for it ? B. In the nature of things, I think. A. What if it arises from your own nature ? B. Certainly not from there alone. For it is neccessary that my nature and the nature of things that I'm thinking about are such that, when I proceed using a legitimate method, I infer a proposition of the sort that is at issue, that is, I find a true proposition. A. You repond nicely, But there are difficulties. B. What are they, I beg of you ? A. Certain learned men think that truth arises from decisions people make, and from name or characters. B. This view is quite paradoxical. A. But they prove it this way: Isn't a definition a starting place for a demonstration ? B. I admit that it is, for some propositions can be demonstrated only from definitions joined to one another. A. Therefore, the truth of such propositions depends on defintions. B. I concede that. A. But defintions depend upon our decision. B. How so ? A. Don't you see that it is a matter of decision among mathematicians to use the word "ellipse" in such a way that it signifies a particular figure ? Or that it is was a matter of decision among the Latins to impose on the word "circulus" the meaning that the definition expresses ? B. But what follows ? There can be thoughts without words. A. But not wihout some other signs. See whether you can do any arithmetic calculation without numerical signs, I ask. B. I am very disturbed, for I didn't think that characters or signs were so necessary for reasoning. A. Therefore, the truths of arithmetic presuppose certain signs or characters ? B. That must be admitted. A. Therefore, they depend upon human decision. B. You seem to have trapped me through trickery, as it were. A. These views are not mine, but belong to quite an ingenious writer. B. Can anyone depart so far from good sense as to convince himself that truth is arbitrary and depends on names, when it is agreed that the Greeks, the Latins, and the Germans all have the same geometry ? ------------ To be continued ...