Garry DeWeese (DeWeese@Colorado.edu)
Thu, 09 Apr 1998 11:48:15 -0600

Recently, Massimo Pigliucci commented to Moorad Alexanian:

>[The scientific method] is the only reliable one so far invented by
humans. >See, this is one big difference between us. Scientists and
rationalists are
>content in acknowledging the limits of human understanding, but are
>proud of what we have achieved.

Several points, beginning with definitions:

(i) The scientific method (rather, a family of methodologies) is an
empirical method which may be grounded in either srong or weak empiricism.

(ii) Strong empiricism is the belief that all knowledge of reality comes
through the senses. Weak empiricism is the belief that all knowledge of
material reality comes through the senses.

(iii) Rationalism is the belief that at least some knowledge of reality is

In the quote above, Massimo seems to lump scientists and rationalists into
one camp--but this is mistaken. It is clear from what Massimo has written
that he does not accept non-sensory evidence and so is a strong empiricist.
By these definitions, though, the scientific method does not rule out
knowledge of non-empirically-apprehended reality, but it does rule out the
acquisition of knowledge of such things by the scientific method. Only the
scientific method coupled with strong empiricism leads to a denial of the
non-natural or the supernatural.

I want to argue that strong empiricism is incoherent.

The core of strong empiricism (hereafter simply empiricism) consists of the
following three principles:

(1) Sensory experiences (observations) constitute a person's prima facie

(2) A theory is justified if and only if it belongs to the the simplest
comprehensive theory which explains (most of) a person's prima facie evidence.

(3) The natural sciences, together with the logic and mathematics needed
by them, constitute the simplest comprehensive theory which explains (most
of) a persons experiences/observations.

There are several problems associated with these principles, but the one I
will highlight is that neither (1) nor (2) are empirical statements
(statements of the natural sciences). For what counts as an experience or
observation is not as clear as it seems. Why accept vision and not memory?
Why accept tactile experience and not testimony? The decisions as to what
kinds of things are accepted as prima facie evidence is based largely on
intuition--that is, an a priori intellectual "seeming," which itself is not
an empirical matter.

Indeed, it turns out that intuitions *must* serve as part of a person's
prima facie evidence--and any scientist who reflects on her actual practice
will quickly see this. But intuitions are also indispensible as she
evaluates different hypotheses and seeks to convince others of the
rightness of her preferred theory. But intuitions are not experiences or
observations, and so they cannot count as prima facie evidence.

Perhaps Massimo (or others like him) would reply that his intuitions are
not really serving as prima facie evidence; rather, the history of science
has shown that certain kinds of observations, arguments, procedures,
theories, etc. are *reliable*. But it is not at all clear how he could
show that the history of science has shown these things are reliable
without somewhere employing intuitions as prima facie evidence in
determining reliability.

So if intuitions must figure as prima facie evidence, then since (strong)
empiricism rejects intuitions, (strong) empiricism must be false.

The upshot is that Massimo (and others like him) must in practice rely on a
priori mental deliverances, something which their resultant theory (3)
rejects. So there is a basic incoherence at the very heart of the strong
empiricist program.

(A much expanded and more rigorous form of this argument can be found in
George Bealer and Peter Strawson, "The Incoherence of Empiricism.")

I think, too, that the failure to distinguish between strong and weak
empiricism may be the source of much dissatisfaction with Phil Johnson's
rejection of MN--but this post is too long already.

Garry DeWeese