[lit-ideas] Re: Philosophical points

Phil Enns, with whom I tend to agree, writes:

"If the word 'mortal' is to tell us something interesting about any particular 
example within the set of 'all men', then the sentence "all men are mortal" 
cannot be formalized with the proposition "For all x if x is a man then there 
exists a time t such that x dies at t". There is of course the obviously 
problematic 'there exists', which should be a conversation stopper.  Beyond 
that, it is difficult to see how picking a highly idiosyncratic 'meaning' of a 
sentence (i.e. that mortality refers to a point in time), providing a highly 
idiosyncratic formalization (i.e. 'scientific') of that 'meaning', gives one 
grounds for deciding whether that  sentence is or is not scientific.  Put 
differently, under such particular conditions, I can imagine ruling out any 
sentence as being a scientific hypothesis.  After all, what sentence could not 
render peculiar 'meanings' that would render them unscientific?"

First, I completely agree that "there exists" is a problematic expression.  I 
think, though, that Quine's usage is both decipherable and coherent, though I 
do have my doubts about the entire program within which that usage makes sense.

The usage derives from the notion that time can be treated, for purposes of 
science, as a fourth spatial dimension.  In that sense, one can say "there 
exists" a time t such that..." in the same way one can say "there exists a 
point p such that...".  In this usage one can say "there is a time t such that 
t is greater than 5:00PM EST on March 21 2008 and the sun sets in Washington DC 
at t" and mean something like "the sun will set later this afternoon", tortured 
as such a way of saying it might be.  In the case of the restatement of "all 
men are mortal", this all cashes out as simply meaning that a mortal man will 
die some time, surely not a problematic notion on any construction.

While such circumlocutions may usefully (?) make explicit the logical 
underpinnings of the mathematics which in turn underpin physics, I certainly 
agree that they're of dubious value in the case of "all men are mortal".  I do 
think, though, that to the extent science should be expressible with a logical 
rigor comparable to mathematics (if not entirely resolvable into mathematical 
structures), Quine's formalization would qualify as a way of making explicit 
the aspects of the logical structure of "all men are mortal" which render it 
unfalsifiable, and hence unscientific, at least by Quine's lights.

Next, I don't think Quine's rewrite means that he thinks mortality refers to a 
point in time.  Here's another way of making the point I think Quine was 
making, but referring to a different time:

"For all x, if x is a man then there will be a time t such that if y was the 
time x died, then y < t"

For example, I could say about myself, I will have died before the year 2398, 
or the year 2400 for that matter.  In other words, it just says I'll die 
sometime, without getting hung up on there being (today) a particular time at 
which I'll die.  But Quine's complaint about "all men are mortal" as a 
scientific hypothesis would remain for this formalization as well, since there 
is still no way to find a case that falsifies the statement (i.e. you'd have to 
wait around for all eternity to find one).

Finally I think the there's much confusion generated from the idea that Quine 
would have thought his formulation amounted to a formalization of *the entire 
meaning of* "all men are mortal."  I think he would have seen himself as 
singling out a legitimate and meaningful part of the meaning (everyone's going 
to die sometime) which might sound like the sort of generalization about which 
science might give us useful insight, and then demonstrating that even that 
potentially scientific-sounding bit really can't be treated scientifically.  

While I don't entirely sympathize with Quine's biases about what constitutes 
science, I don't think he's entirely out to lunch about this point, and, as I 
said in my first post, so much the worse for science's ability to illuminate 
the human condition.

Regards to one and all,
Eric Dean
Washington DC

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