In a private correspondence with Bob Phair we started a discussion
on negativism in science which I think might be interesting to the whole
group. I am taking the liberty to quote Bob's metaphor which in my
opinion is nice:
This is not to say that criticism is worthless. Far from it. But <
criticism without the suggestion of a viable improved alternative is a <
lot like walking the streets carrying a sign that says "The World is <
Bad". Everyone knows you have a point, but no one will pay the least <
attention to you.
Yes, this kind of negativism is frequent and dangerous. In fact, everyone
who envies the great brains but cannot reach their hight is tempted to
resort to it. However sometimes negativism is "positive" and I will try to
show this on a concrete example.
Let us consider a simplified formulation of the second law of
themodynamics: "A system cannot do work cyclically and isothermally (i.e.
it cannot convert, isothermally, heat into work)". We are interested in
chemical systems, so we take one, let it be the ATP-ADP-P system, and try
to verify whether the second law (in this formulation) is valid for it.
What should we do? Of course to assess the work done by the system in a
chemical process and then in a cycle. However a difficulty arises:
thermodynamics says nothing about the work done in an irreversible process;
it only tells us the value (delta G) of the maximum work done in a
REVERSIBLE process. This means that we can only verify the second law for
a reversible process. But who can cite an experiment in which ATP does work
reversibly? This can only be done in rather unrealistic thought experiments
of which nobody is interested. The confusion is so great that Guy Brown
even wrote on 3 June 1997: "I do not think that the work extractable from
a chemical reaction is of any importance (unless perhaps it is mechanical
work)".
This is rather illustrative - on one hand, we firmly believe in a
statement (the second law) about the work done in a cycle etc.; on the
other, this work is of no importance.
Situations of this kind are dealt with by Karl Popper - in them he
applies the falsification criterium (I am not sure that this is the right
term in English): no theory is a theory unless it provides the means of
its refutation. I do not think that classical chemical thermodynamics has
done this. On the contrary - verification is extremely difficult and
even impossible.
If so, criticism is absolutely legitimate - it is not just negation -
rather, it aims at providing the theory with what is missing, i.e. with
its falsification criterium.
Simultaneously, one can develop the alternative - instead of "A system
cannot do work..." one might be able to show that "The system CAN do work..."
and if this alternative is successful, the second law would prove
to be "negativism" and the new alternative "positivism". Of course, this
last statement is not very serious.
I promised to Bob Phair to post, in a few days, the principles of
thermodynamic analysis in which the concept of chemical work is liberated
from its mysticism and can be successfully used. I hope the group will
be interested.
Pentcho
