On Post Modernism and Scientific Certainty.
November 8, 2010
A friend writes:
I think we are all postmodernists
in the sense that we are critical and don't accept absolutes. You talked
about the "laws" of science. They are only hypothetical, tentative.
Heisenberg. John Dewey talked about "warranted assertibility." Some
ideas are better than others. But still, we can measure things, [even
though] the measuring instruments aren't exact and the things we are
measuring are moving.
My reply:
I am not a post-modernist, in that I firmly believe that there are numerous
scientific laws that are "practically certain," though they are in principle
not "absolute." If a scientific law can be affirmed with 99.99% confidence,
I take that to mean "practically certain."
All scientific assertion, to be meaningful, must be falsifiable. I.e.,
implicit in a scientific assertion must be a clear understanding of what the
world would be like if the assertion were not true. For example, Galileo's
equation for a free-falling object: distance = 1/2gravity x time squared.
Not 1/3 or 1/4 or any other fraction x gravity, and not time cubed, or to
the 1.5 power. In short, not any of an infinite number of alternative
equations which would prove his equation false.
Similarly, Eddington's eclipse experiment confirmed Einstein's equation, E=mc2
Had the star near the eclipse appeared anywhere other than where it
appeared, Einstein's equation would have been proven false. But it appeared
exactly where the equation predicted that it would. Also evolution, which
would be false if the fossil record, comparative DNA analysis, animal
husbandry, comparative anatomy, etc., were different from what they are.
The falsifiability criterion carries an important implication: what C. S.
Peirce called "falliblism:" namely, that for any assertion (including all
scientific assertions) to be meaningful, it must be logically possible for
the assertion to be proven wrong. And if a meaningful assertion must be
falsifiable, then no meaningful assertion is absolute.
But the difference between practical certainty and logical certainty
(absolute) can at times be so infinitesimal, that it can be ignored.
For example, consider this generalization: "decapitation is always fatal."
(Falsification: the old English "Ballad of Ann Boleyn:" "With 'er 'ed
underneath 'er arm, she walks the bloody Tower.") We know what it would be
like for the assertion to be false and all future decapitations can not be
included in the "always," but I would stake my own life on it's being true
-- on my never encountering some bloke walking around with his severed head
underneath his arm.
The "practically certain" truth of thousands of scientific laws is confirmed
daily through the successful operation of technology. If Ohm's Law were
different by one percent from what it is known to be, this computer would
not boot up. If Newton's Laws of motion or Kepler's Laws of celestial
mechanics were wrong by a fraction of one percent, the Apollo missions would
have failed, and synchronous orbit communications satellites could not be
put in place. Engineers and inventors routinely assume these thousands of
natural laws which, were they any different, would result in their gadgets
not working.
Now that's a kind of "pragmatic warranted assertability" that John Dewey
would endorse. It's one thing to talk in high abstractions about "falliblism"
and the rejection of absolutism, but quite another when bring it all down to
the raw specifics of ordinary experience. There we might find that
possibility of falsifying some scientific laws as 0.0001%. I see no reason
for not calling such a law "certain."
Yet post modernists, as I understand them (or at least some of their naive
camp-followers), are quite content to proclaim that science is just another
belief system, no better or worse than any of the others. Cf. the ongoing
debate over global warming.
Well, I beg to differ: Science is not "just another dogma," as I argue in my
essay, "Is
Science Just Another Dogma? (See especially the section "Scientific
Assertions are Fallible and Falsifiable")
Now much of PoMo's subjectivism and relativism ("the meaning of the text is
its interpretation, nothing more") has merit regarding such non-scientific
endeavors as literary criticism, metaphysics, ethics, economics, etc. But to
extend this subjectivism and relativism to the "hard sciences" seems to me
to be a clear commission of the fallacy of false generalization.
To quote the late physicist Richard Feynman, "reality must take precedence
over public relations, for nature can not be fooled." Well, today public
relations is taking precedence over reality. And no amount of corporate PR,
media control, and political bribery can add a single drop of petroleum in
the ground to forestall "peak oil," nor can it alter the laws of atmospheric
physics and chemistry which foretell catastrophe if we fail to heed our
scientists and change our policies.
Which explains, perhaps, why I am so impatient with and critical of those
who devalue the accumulated body of hard science -- politicians, corporate
PR hacks, and of course, post-modernists.
. . . .
On a personal note: I have endured a lifetime of
science-denying nonsense from my Mormon relatives, to be followed by more of
the same in my last academic appointment. (See my
"Yes Virginia, there is a
real world"). Retirement gave me no respite, for now I have to contend
with libertarian friends who insist that global warming is a hoax, and thus
that the entire world-wide cohort of atmospheric scientists are involved in
a vast conspiracy in order to get government research grants. And, of
course, I am constantly reminded that I live in a country, half the
population of which refuses to believe in evolution.
Some post-modernists give aid and comfort to this nonsense, which,
admittedly, gets me "riled up."
On reflection, I suspect that I wrote this rant more for my benefit than
yours. It was clear and explicit response to the anti-science and
anti-rationalism that is rampant in our society today. I suspect that some
of that rant may end up in my chapter on Science in Conscience of a
Progressive.
That said, I do agree, as you say, that "the postmodernists do point out
many of the nuances of problems, such as with prisons, mental institutions,
race and gender, that other philosophies miss." But these are moral issues,
quite apart from the attack on science.
