[lit-ideas] Re: The Immortality of Popper
- From: Donal McEvoy <donalmcevoyuk@xxxxxxxxxxx>
- To: "lit-ideas@xxxxxxxxxxxxx" <lit-ideas@xxxxxxxxxxxxx>
- Date: Sat, 5 Jan 2013 15:41:06 +0000 (GMT)
JLS, Happy New Year (and the same to anyone else out there). But getting down
to business..
----- Original Message -----
From: "Jlsperanza@xxxxxxx" <Jlsperanza@xxxxxxx>
>We are considering a syllogism that Popper criticised. It's called Barbara:
All men are mortal.
Popper is a man.
--- Therefore, Popper is mortal.>
Popper does not criticise this syllogism - far from it: it is a valid deductive
syllogism. And its validity is a linchpin of Popper's hypothetico-deductive
account of science.
The "syllogism" Popper disputes is the _inductive_ one as follows:
Popper is a man and a mortal
Socrates is a man and a mortal
Plato is a man and mortal
---Therefore, all men are mortal.
In the case of this inductive "syllogism" the positive instances are claimed to
constitute valid supporting evidence such that they render "All men are mortal"
either true or probably true in some inductive sense. In Popper's (correct)
view these positive instances no more constitute valid supporting evidence of
such a sort than they constitute valid supporting evidence for the conclusion
"All mortals are men".
Why would no one - except perhaps a learned inductivist - regard these positive
instances as valid supporting evidence for "All mortals are men" - well,
because they know of animals that have died. In other words, because they know
of counter-examples.
It is the absence of counter-examples that is vital to whether a claim of a
general sort - whether "All men are mortal" or "All mortals are men" - might be
true [_"might"_because absence of a counter-example is a necessary, but not
necessarily sufficient, condition of the truth of such a general claim]. It is
the rigorous search for counter-examples that lies at heart of scientific
method, not the search for positive or confirming examples - indeed, the value
of positive or confirming examples is not more than their value as showing the
absence of a counter-example.
So JLS's contention is mistaken - both as a claim as to what Popper criticises
and as to what is invalid. For the deductive "syllogism" is valid and is not
one Popper criticises but instead takes as a linchpin of scientific and
rational thinking.
>Popper proved that it is testable that "Popper is mortal" is observable.
Hmm. This too seems to the product of some confusion of thought [despite the
fact that it is true that the state of being dead may be "observable" or
testable by observation, in contrast to the state of being "immortal" which is
not "observable", and so "Popper is mortal" is observable:- for this fact would
not mean this fact may itself be "proved" in a testable way i.e. just because
we may observe Popper 'in a state of being dead' would not mean that the claim
"Popper 'being dead' is observable" is itself observably true or testable _in
that same sense_]. But am tiring now; and am more drawn to saying something in
reply to another post that suggests Popper is Cartesian. On this we might wish
to clarify the similarities and differences between Popper and Descartes [the
main similarity is that they are dualists-interactionists as to mind and body],
but this perhaps belongs in another thread - it has little to do with the
"syllogisms" discussed here.
Donal
Wild in the country
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