logicalpath Posted March 31, 2011 Report Share Posted March 31, 2011 Today I was doing some research on "The Law of Identity" and I ran into a problem. When I was reviewing "Works of Aristotle" I could not find any mention of "The Law of Identity" nor could I find a specific outline of "A is A". As a result I began searching online to see if my book was missing something important. I found this link which claims that Aristotle never actually said any of it...not specifically anyway. Can someone point me in the right direction or shed some light on this for me? Quote Link to comment Share on other sites More sharing options...
Trebor Posted March 31, 2011 Report Share Posted March 31, 2011 (edited) In Episode 92 of his podcasts, Dr. Peikoff is asked: 00:48: "'Could you please tell me where I can find Aristotle's reference to the law of identity?'" Here on his site as a single question and answer. Edited March 31, 2011 by Trebor Quote Link to comment Share on other sites More sharing options...
logicalpath Posted March 31, 2011 Author Report Share Posted March 31, 2011 In Episode 92 of his podcasts, Dr. Peikoff is asked: 00:48: "'Could you please tell me where I can find Aristotle's reference to the law of identity?'" Here on his site as a single question and answer. Thank you for your help, I appreciate it. Quote Link to comment Share on other sites More sharing options...
Trebor Posted March 31, 2011 Report Share Posted March 31, 2011 You're welcome. Isn't the law of identity implicit in the law of contradiction and the law of excluded middle? Quote Link to comment Share on other sites More sharing options...
Grames Posted March 31, 2011 Report Share Posted March 31, 2011 Isn't the law of identity implicit in the law of contradiction and the law of excluded middle? I agree that it is implicit. Contradiction is a word meaning "to be and not be, at the same time and in the same respect." This is the same as "A and not-A" or "A is not-A". The metaphysical claim that contradictions do not exist negates the statement "A is not-A" into "A is not not-A", and the double negative on the last term cancels to "A is A". I like this passage from the wikipedia entry on the Law of excluded middle The Principle of Excluded Middle, along with its complement, the Law of Contradiction, are correlates of the Law of Identity; the first principle of thought (reason). Because the principle of identity intellectually partitions the Universe into exactly two parts: ‘self’ and ‘other, it creates a dichotomy wherein the two parts are ‘mutually exclusive’ and ‘jointly exhaustive’. The principle of contradiction is merely an expression of the mutually exclusive aspect of that dichotomy, and the principle of excluded middle is an expression of its jointly exhaustive aspect. Quote Link to comment Share on other sites More sharing options...
m082844 Posted April 2, 2011 Report Share Posted April 2, 2011 I got this recently in a book called "Atheism: The Case Against God" Law Of Identity: A is A Law of Excluded Middle: Anything is either A or non-A Law of Contradiction: Nothing can be both A and non-A at the same time in the same respect Quote Link to comment Share on other sites More sharing options...
Tanaka Posted April 4, 2011 Report Share Posted April 4, 2011 Aristotle said that "a thing is itself" and demonstrated that this statement is an axiom, in Metaphysics (Book VII). That's the Law of Identity. A is A (I believe Thomas Aquinas was the first to state the law of identity in this manner) means exactly the same thing, because A is meant as a placeholder for one (any one) existent: that's exactly the meaning of the concept "a thing". Quote Link to comment Share on other sites More sharing options...
dream_weaver Posted April 4, 2011 Report Share Posted April 4, 2011 A link to Aristotle's Metaphysics (Book VII) compliments of The Internet Classics Archive. Quote Link to comment Share on other sites More sharing options...
Leonid Posted April 5, 2011 Report Share Posted April 5, 2011 logicalpath :"When I was reviewing "Works of Aristotle" I could not find any mention of "The Law of Identity" nor could I find a specific outline of "A is A". " No wonder.The Laws of Aristotle are 1. The Law of Contradiction.2. The Law of excluded Middle. The Law of identity, A is A, had been formulated not by Aristotle but by philosopher Antonius Andreas in 12th century A.D. However, this Law obviously presents the same essential points of Aristotelian laws. Quote Link to comment Share on other sites More sharing options...
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