# [OPE-L:7163] [OPE-L:670] equality, identity, and value

Gerald Levy (glevy@pratt.edu)
Sun, 14 Mar 1999 12:54:03 -0500 (EST)

---------- Forwarded message ----------
Date: Sun, 14 Mar 1999 17:32:33 +0000
From: "C. J. Arthur" <cjarthur@pavilion.co.uk>
To: Gerald Levy <glevy@pratt.edu>
Subject: Re: [OPE-L:662] equality, identity, and value

Jerry is right below.
It is most unfortunate Tarski conflates identity and equality . Quote from
Gil's post [to which I will reply later]:
"It occurs in phrases such as: 'x is identical with y,' 'x is
the same as y,' 'x equals y.' To all three of these expressions the same
meaning is ascribed; for the sake of brevity, they will be replaced by the
symbolic expression: 'x =y.' "
This is contrary to common usage and common sense as the example of 3=2+1
someone cited shows.
Since what is at issue is Marx's argument we have to start from his own
gloss on a=b - this is 'a is worth b'.
This not only does not suppose a and b are identical it prohibits it, as
marx goes on to make explicit when he denies a=a is a relation of value. I
would argue furthermore that, in the value relation 'a is worth b,' a and b
do not have to be identical in any repect whatsoever. Taken abstractly,
given that a commodity on its own does not contain an atom of value and
that this is a 'purely social substance' a's value can only be given in
some b *different from it*. Ultimately, as Brendan correctly argued
earlier, it requires the price form.
The inference that a and b must both be labour products requires more
argument than Marx gives in chapter 1.

Chris Arthur

L>Both Chai-in and Steve have asked about why the issue I raised in [658]
>has come up now.
>
>
>In [651], Gil placed great stress on the "1 quarter of corn = x cwt of
>iron" being an "*equation*". He went on to add:
>
>> Saying one bundle is exchanged for another is not generally the same as
>> saying that one bundle equals another.
>
>My response in [658] was intended to show that simply because there is
>an "=" sign does not establish that 1 side of the "equation" is equal to
>the other side in all respects.
>
>Chai-on points to the difference between identity and equality.
>
>Yet Gil had previously in [653] quoted Tarski as suggesting that "the same
>meaning is ascribed".
>
>So perhaps Chai-on is using different definitions of equality and identity
>than those used by Tarski and Gil.
>
>Let's step back a moment.
>
>*Every* economic theory has a theory of value (whether it is explicitly
>stated or inferred).
>
>One of the major questions that a theory of value answers is: what
>determines exchange-value? If you can't answer that question, then you
>can't have a theory of (any type of) price either.
>
>Obviously, it would be a tautology to say that exchange-value determines
>exchange-value.
>
>Is it marginal utility, as suggested by the marginalists? If Gil and Steve
>think there are problems with Marx's theory, what about the marginalists'
>theory? E.g. what is a "util" and how is that fiction measured?
>
>A theory of value could be based on physical quantities. If that is the
>case, how does money enter the picture except as a numeraire?
>
>What I don't hear Steve or Gil suggesting, then, is an *alternative*
>theory of value.
>
>In solidarity, Jerry