Re: Popper's 'Scientific' Irrationalism

Robert Schrader (
Wed, 19 Mar 1997 18:38:22 -0800 (PST)

On Wed, 19 Mar 1997, Reilly Jones wrote:
> All right, out of the purest, most unselfish, highest altruistic extropian
> motives, I will, as a public service to all interested newbies on the list,
> repost the fatal criticism of Popper's falsifiability principle.

Your virtues are legendary and greatly admired. It's truly a pity that
taste in scientific philosophers is not one of them. :)

> >From "PHIL: Questioning Popperianism" 3/8/95:
> Quotes from Elliott Sober's "Philosophy of Biology" (1993):
> "Popper's criterion of falsifiability requires that we be able to single
> out a special class of sentences and call them observation sentences. A
> proposition is then said to be falsifiable precisely when it is related to
> observation sentences in a special way: Proposition P is falsifiable if
> and only if P deductively implies at least one observation sentence O. One
> problem with Popper's proposal is that it requires that the distinction
> between observation statements and other statements be made precise. To
> check the statement 'The chicken is dead,' you must know what a chicken is
> and what death is. *This problem is sometimes expressed by saying that
> observation is theory laden.* Every claim that people make about what
> they observe depends for its justification on their possessing prior
> information. Popper addresses this problem by saying that what one regards
> as an observation statement is a matter of convention. But this solution
> will hardly help one tell, in a problematic case, whether a statement is
> falsifiable. For Popper's criterion to have some bite, there must be a
> nonarbitrary way to distinguish observation sentences from the rest. To
> date, no one has managed to do this in a satisfactory manner.

This is a linguistic problem, not a scientific/logical one. To communicate
at all we have to use a bunch of arbitrary conventions. It's part of
having a common language. But once we have those in place, we can talk
of falsifiable statements. Sober speaks as though conventions had to
be invented anew with every conversation.

> The problems with Popper's falsifiability criterion go deeper. First,
> there is the so-called tacking problem. Suppose that some proposition S is
> falsifiable. It immediately follows that the conjunction of S and any
> other proposition N is falsifiable as well. That is, if S makes
> predictions that can be checked observationally, so does the conjunction S
> & N. This is an embarrassment to Popper's proposal since he wanted that
> proposal to separate nonscientific propositions N from properly scientific
> propositions S. Presumably, if N is not scientifically respectable,
> neither is S & N. The falsifiability criterion does not obey this
> plausible requirement.

There is nothing inherently plausible here. Indeed, the fact that N _can_
corrupt S is yet another demonstration of the difference between N and S.
( Compare to the proposition 'S1 and S2' )

{ It's dinner time here. Sober's 3rd and 4th errors will be addressed
after dessert }

Robert Schrader