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Law of Identity
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Law of Identity

Makarismos
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Posted 07/30/08 - 12:13 PM: Subject: Law of Identity	#1
Some have attributed the law of identity to Aristotle, but I have been rather fascinated with he idea that it wasn’t actually him who postulated it. See here:- http://www.geniebusters.org/915/04e_ex01C.html Still the law is quite well known, even if it does not originate with Aristotle. It is usually formulated as a is a, or p -> p, or something similar. My question is this:- Is the law of identity useful at all? is it axiomatic to rational thought, or is it a trivial point which does not need stating? Also, can it be used to prove things in this kind of way:- junk wrote: To have an identity means to have a single identity; an object cannot have two identities. A tree cannot be a telephone, and a dog cannot be a cat Your thoughts?

muxol
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Posted 07/30/08 - 01:18 PM:	#2
All I can recall concerning the history of the law is that the Peripatetics denied it. They thought it a form of circular reasoning. You should consult a reliable source (so not the url you cite) such as Kneale and Kneale's "The Development of Logic". There is a very weak relevant logic called 'S' (P - W - identity) that does not validate identity. You might find that of little interest.

Makarismos
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Posted 07/30/08 - 01:55 PM:	#3
Eli_Hirsch wrote: One important difficulty with this notion has to do with deciding when an analysis is "circular", when, that is, the concepts in terms of which it is couched depend, in some sense, on the concept being analysed. This difficulty may seem potentially devastating when the concept to be analysed is as fundamental to our overall thought as the concept of physical persistence. http://books.google.co.uk/books?id=L-uosYsNTBIC&d... He goes on to say that it seems that this concept is in certain respects un-analysable, but my question is more - is such analysis useful in any reasoning that anyone knows of? Especially any contemporary reasoning, especially concerning non-abstract philosophy (i.e. outside the realms of pure logic or mathematics).

Kelby
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Posted 07/30/08 - 06:21 PM:	#4
Though their are many problems with her line of thought, Ayn Rand makes use of the law of identity quite frequently. It becomes quite pragmatic in her eyes as she also finds axioms far from truisms. She finds axioms to be the base of how we think about corollary propositions and any idea that contradicts basic axioms is a fallacy. In this respect, I agree with her since I do not believe what people deem as truisms as truisms. Something is only a truism to someone because they are ignorant of the implications of such a "truism." "Existence is" is claimed as a truism because there is nothing more obvious than that. Therefore, it is meaningless and should never be stated. By definition a truism is something so common to all knowledge that it is meaningless. Well...if existence exists is so common to all of our knowledge to be meaningless, then why do so many philosophies deny existence? If all thought come from our brain is a truism, then why do so many people deny it? In relation to a=a... this may not be a truism or a tautology of any sort. It only becomes one when one is ignorant of the implications present within a specific context. Too many philosophical ideas actually deny this very "axiom." Every idea that wanes towards the possibility of nonexistence denies the law of identity. Existence is, because a=a. Non existence also is something because b=b. Before we can even discuss nonexistence we have to be discussing something at all, and this would make nonexistence an existent. Existence is identity.
Embodied Cognition: http://www.iep.utm.edu/e/embodcog.htm#H2

Banno
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Posted 07/30/08 - 07:40 PM:	#5
The law of identity is somewhat useful, since if one denies it, anything follows. Perhaps this is what Kelby is demonstrating.
Davidson: We make maximum sense of the words and thoughts of others when we interpret in a way that optimizes agreement. Russel Morris: There's a meaning there, but the meaning there doesn't really mean a thing...

Cuthbert
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Posted 07/31/08 - 12:44 AM:	#6
I think Ayn Rand thought that everything is what it is. But she might occasionally have mistaken that axiom for another similar one: if Ayn Rand thinks that everything is what it is, then everything is what Ayn Rand thinks it is. It's an easy mistake to make. I'm sure I've done it myself.

Kelby
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Posted 07/31/08 - 02:47 AM:	#7
Banno wrote: The law of identity is somewhat useful, since if one denies it, anything follows. Perhaps this is what Kelby is demonstrating. that's basically what I was saying. In order to progress in thought, if there is such a thing, the very process of thinking needs to be restricted to a specific framework. Thinking cannot be simply anything you want it to be as long as I'm contributing. Well, what is considered contribution is restrictive. Anything cannot be science. Anything cannot be philosophy. Usually there are strict rules for what constitutes science and philosophy. Axioms, or "truisms" or foundations are necessary as a framework. They allow us to think within this framework and continually restructure our thoughts if we ever veer off the course into nonsense. I recently posted on another website (ephilosopher) and I said that all of our thoughts, reason, emotions, etc are biological processes and someone responded quite harshly to my claim. They told me not to post anything everyone already knew. Well...the arguments prior to my post seemed to be ignorant of the basic fact that we are biologically madeup and we have brains. They discussed things as if they understood the Universe as it really is objectively, free from any perceiver. Apparently the knowledge of the biological makeup of humanity wasn't as common as this person believed. Just because we know something when it is stated does not mean that one has thought extensively about the implications of that knowledge. I may know that we see color through rods and cones. Great! But when one thinks about what that implies, then something entirely amazing happens. One realizes there is no objective or subjective color. There is only an interactive existence for color. Therefore, there are no primary qualities...only secondary. So when we claim something as a truism....maybe we should think a little deeper on what it implies.
Embodied Cognition: http://www.iep.utm.edu/e/embodcog.htm#H2

Banno
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Posted 07/31/08 - 04:30 AM:	#8
Cool. But I wouldn't say that logic is a restriction on thinking. Rather it marks the difference between good and bad thinking.
Davidson: We make maximum sense of the words and thoughts of others when we interpret in a way that optimizes agreement. Russel Morris: There's a meaning there, but the meaning there doesn't really mean a thing...

et cetera
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Posted 07/31/08 - 06:54 AM:	#9
I think identity is one of the most important concepts in philosophy and logic. "A is A" is too narrow of a definition for me, it only shows the self-identity of a particular object. Of course it is trivially true that a object is identical to itself. what is more interesting in my mind is the synonymy of referring expressions such as water is identical to H20. aposteriori identity claims are not trivial, their content or reference is not known by access alone to thought, and very much so drive the progress of emipircal science or if i am over generalizing help to successfully categorize it. Edited by Tobias on 07/31/08 - 12:39 PM
Any necessary truth, whether a priori or a posteriori, could not have turned out otherwise. -- Saul Kripke Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word. -- Quine A possible world is given by the descriptive conditions we associate with it - Kripke

et cetera
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Posted 07/31/08 - 06:59 AM: Subject: Also Leibniz law	#10
Also Leibniz law states that two objects are identical if and only if they share all the same properties. I think this definition is of particular interest. Are there any two individual objects that have all the same properties which we can claim are identical? Surely they are not identical in extension but they can be indentical in quality (you know those primary and secondary things). Why can't the senses be relied upon in constructing a positive theory of empirical knowledge atleast within regards to the relationships between concievable objects. The intentional object does not give us access to the actual object and the actual object is of little importance to our conceptual undertstanding. The reference has no signification. It is a barron waste land, it is what it is, it is undifferentiated and despite. Forever known as the x, the a, the b, and the c of our formal logics. What is of interest are the indefinite number of orders and predicate used to describe the object. Actually meaningful discussion comes from understanding the percieved structure, function, and properties of objects and is sufficient for claiming identity for two objects which have distinct references. In my mind it matters little whether or not (x) is not the same as (y) if all we really mean by sameness, identity, and difference is encapsulated by universals and their instatiations. Granted everything you see is an allusion, a trick of the central nervous system within regards to this Mysterious(x), yet i think this is irrelevant to the metaphysics of empircal science. Whats wrong with identity as a pragmatic convention used to create type distinctions? If i had two black boxes of the same dimensions and qualities then indiscriminately rearranged them. Why does it matter which box is (x) or (y) they are both black boxes identical in all percievable qualities and presummably structure? What is so interesting about the self identity of (x) besides the sum of all its conceievable properties? And go for the jugular one more time, in virtue of what do you say that both of the boxes are black? Putnamian magic? also epistemic contextualism has some sway here. Why put such horrible semantic restriction on what we call knowledge for no concievable reason except for a fear of scepticism? If you want me to answere "what is knowledge" i would prefer to remain silent (this being one of my only agreements with Wittgenstein) for I personally fear how extreme your epistemological requirements are. Edited by et cetera on 07/31/08 - 06:27 PM
Any necessary truth, whether a priori or a posteriori, could not have turned out otherwise. -- Saul Kripke Meaning is what essence becomes when it is divorced from the object of reference and wedded to the word. -- Quine A possible world is given by the descriptive conditions we associate with it - Kripke

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