Chapter 5. (continued)
Many empiricist philosophers see AI as our
best hope for defining, once and for all, what thinking is. AI offers a model
of our own thinking that explains it in ways that can be tested. A program
written to simulate thinking either runs or fails, and every line in it can be
examined. When we can write programs that make computers converse with us so
well that, when we talk to them, we can’t tell whether we’re talking to a human
or a computer, we will have encoded what thinking is. Modeled it so that
programmers can explain it with algorithms. Run the program and observe what it
does. Repeat.
With the rise of AI, cognitive scientists
felt that they had a real chance of finding a model of thinking that worked,
one beyond the challenges of the critics with their counterexamples.5
Neurology, behavioral science, or AI –
these are currently the best paths along which we might get to a purely
empiricist explanation of what thinking is. They begin from evidence that all
can witness. That fits Empiricism.
Testability in physical reality and
replicability of the tests, I repeat, are the characteristics of modern Empiricism
(and of all Science). All else, to modern empiricists, has as much reality and
as much reliability to it as creatures in a fantasy novel. Ents. Orcs. Sandworms.
Amusing daydreams, nothing more.
Kurt Gödel (credit:
Wikimedia Commons)
For years, the most optimistic of the
empiricists looked to AI for models of thinking that would work in the real
world. Their position has been cut down in several ways since those early days.
What exploded it for many was the proof found by Kurt Gödel, Einstein’s
companion during his lunch hour walks at Princeton. Gödel showed that no
rigorous system of symbols for expressing human thinking can be a complete
system. Thus, no system of computer coding can ever be made so that it can
adequately refer to itself. (In Gödel’s proof, the ideas analyzed were basic
axioms in Arithmetic.) Gödel’s proof is difficult for laypersons to follow, but
non-mathematicians don’t need to be able to do formal logic in order to grasp
what his proof implies about everyday thinking.6
Douglas Hofstadter (credit:
Wikipedia)
If we take what it says about Arithmetic
and extend that finding to all kinds of thinking, Gödel’s proof says no symbol system
for expressing our thoughts will ever be powerful enough to enable us to
express all the thoughts about thoughts that human minds can dream up. In
principle, there can’t be such a system. In short, what a human programmer
does as she fixes flaws in her programs is not
programmable.
What Gödel’s proof implies is that no way
of modelling the human mind will ever adequately explain what it does. Not in
English, Logic, French, Russian, Chinese, Java, C++, or Martian. We will always
be able to generate thoughts, questions, and statements that we can’t express
in any one symbol system. If we find a system that can be used to express some
of our ideas really well, we discover that no matter how well the system is
designed, no matter how large or subtle it is, we have other thoughts that we
can’t express in that system at all. Yet we must make statements that at least
attempt to communicate all our ideas. Science is social. It has to be shared in
order to advance.
Other theorems in Computer Science offer
support for Gödel’s theorem. For example, in the early days of the development
of computers, programmers were frequently creating programs with “loops” in
them. After a program had been written, when it was run, it would sometimes
become stuck in a subroutine that would repeat a sequence of steps from, say,
line 79 to line 511 then back to line 79, again and again. Whenever a program
contained this kind of flaw, a human being had to stop the computer, go over
the program, find why the loop was occurring, then either rewrite the loop or
write around it. The work was frustrating and time consuming.
Soon, a few programmers got the idea of
writing a kind of meta-program they hoped would act as a check. It would scan
other programs, find their loops, and fix them, or at least point them out to
programmers so they could fix them. The programmers knew that writing a check
program would be hard, but once it was written, it would save many people a
great deal of time.
However, progress on the writing of this
check program met with problem after problem. Eventually, Turing published a
proof showing that writing a check program isn’t possible. A foolproof
algorithm for finding loops in other algorithms is, in principle, impossible.7 This
finding in Computer Science, the science many see as our bridge between the
abstractness of thinking and the concreteness of material reality, is Gödel all
over again. It confirms our deepest feelings about Empiricism. Empiricism
is useful, but it is doomed to remain incomplete. It can’t explain itself.
Arguments and counterarguments on this
topic are fascinating, but for our purposes in trying to find a base for a
philosophical system and a moral code, the conclusion is much simpler. The more
we study both theoretical models and real-world evidence, including evidence
from Science itself, the more we are driven to conclude that the empiricist way
of understanding what thinking is will probably never explain its own method of
reaching that understanding. Empiricism’s own methods have ruled out the
possibility of it being a base for epistemology. (Define the word meaning?)
(In Algebra, solve x2 + 1 = 0).