[hist-analytic] Kripke and Contiingently Necessary Truth!?
Baynesr at comcast.net
Baynesr at comcast.net
Fri Nov 6 14:59:45 EST 2009
I don't follow Bruce's description in terms of "common
sense." Kripke never discusses this. Here is my take.
We identify heat by the sensations it produces in us.
This is a contingent property. There is nothing here about
"common sense." The referent of 'heat' is fixed by this
contingent property; 'heat', then, supposedly denotes the same thing
in all worlds, viz. "molecular motion."
Thus, IF the identity statement is correct, 'heat'
denotes molecular motion in all possible worlds. But
now it turns out that the contingent property we use
to fix the referent is also had by processes not involving
molecular motion at all! We are faced with two possibilities.
1. We can admit to being wrong in saying that 'heat is
molecular motion'. But then what is it heat has in common
with all its instances, if anytyhing?
2. We can attempt to identify all that is captured by
the sensation that fixes the referent of 'heat' with
something else. But what?
(2) is out, since there is no "something else." Changing
how we measure temperature is no help. So we are left
rejecting (1). If we admit to (1) then we are back to
"analyzing" heat, not 'heat'. But now there are serious
questions. The heat of the fire IS identifiable with
molecular motion; the heat of the plasma is not identifiable
with molecular motion. Ergo, in the first instance we have
a true identity, but it is not necessary, even though the
terms are rigid! This is because 'heat' does not refer to the
same thing even in this world. The same contingent property
can fix a single term in two ways incompatible with one
Kripke's theory (or lack of one) concerning microprocesses
is not at issue. Not in the least. What is at issue in this instance
is the non-necessity of identities where the designators are rigid
ex hypothesis. Again, in the case of the fire heat IS molecular motion;
in the case of plasma it is not. Therefore, 'heat' is not
a rigid designator or not all identities are necessary.
Here is the risk for Kripke if this holds water:
the notion of a "cluster theory" of reference will be
reintroduced by way of disjunction: 'heat is molecular
motion or P^1 or P^2 etc.'
Now as for the last paragraph of Bruce's message, I think
Kripke addresses his particular concerns at pp. 136-138
of NN. I may be wrong, but it looks that way to me, at
----- Original Message -----
From: "Bruce Aune" <aune at philos.umass.edu>
To: Baynesr at comcast.net
Cc: "hist-analytic" <hist-analytic at simplelists.co.uk>
Sent: Friday, November 6, 2009 8:05:38 AM GMT -05:00 US/Canada Eastern
Subject: Re: Kripke and Contiingently Necessary Truth!?
I am not sure what to say about Steve’s proposed counter example to Kripke’s identity statement, “heat = molecular motion.” Kripke’s idea was that if in all circumstances in which we apply the commonsense term ‘heat’ a certain kind of molecular motion is taking place and vice versa, then we may justifiably assert that heat is that kind of molecular motion. Kripke offered no scientific details, and I doubt that he is committed to the idea that micro-processes in question involve one kind of micro process rather than another—molecules, say, rather than ions. (From what I remember of organic chemistry, it might be true that molecular interactions are always ionic reactions, H 2 O being, for instance, an aggregate of H 3 O + and OH - ions.)
But Steve’s example does bring to mind a difficulty with the alleged identities involving common sense and theoretical concepts, a difficulty that has always made me doubt the truth of such identities as water and H 2 O. The difficulty is that the various substances picked out by “water” do not have any single micro-analysis. As I expressed the point in chapter 5 of my book:
“No one supposes that a homogeneous substance actually fills all our lakes, ponds, and streams or that the liquids in those different geographical sites are chemically identical. Although we have very good reason to believe that any water we drink, swim in, or sail on consists largely of H 2 O, our normal means of identifying a sample of water does not depend on this belief or on any other chemical lore. A chemist can tell us what proportion of a given liquid is H 2 O or what other compounds it contains, but the decision to apply the label “water” to the liquid in the Cuyahoga river (which once caught fire), the Campus Pond at my university (which is often black and murky owing to the presence of thousands of migrating aquatic birds), the Dead Sea (which is heavily saline), or a highly diluted gallon of what was once Chardonnay wine, will not depend on such a person’s decision. In fact, if our acid rain began to contain substantial amounts of the chemicals making up the XYZ liquid that fills the rivers and ponds of Putnam’s Twin Earth without any significant effects on its ability to quench the thirst of animals or contribute to the growth of familiar plants, ordinary people would call it “water” without hesitation and continue to do so if, owing to some extraordinary natural change, it became pure XYZ. These and comparable other facts make it evident, I believe, that a meaningful reference to water does not depend, conceptually or semantically, on any set proportion of actual H 2 O in the liquid a normal person is thinking of. A person with a smattering of chemistry might, of course, conceive of water as H 2 O, but this conception would be anomalous in practice, for no water most persons have ever drunk is close to being pure H 2 O. Good drinking water is heavily dependent on its mineral content.”
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