Russel asked:

Whenever I have been taught any of the Hume's theories I find myself stuck at the same point every
time. If I have understood him correctly then he takes the idea of empiricism to an illogical conclusion.
i.e. that nothing can be established or proved outside of empirical experience. If this is true then how
can he appeal to his intellectual faculties in order to justify this claim? It seems he relies on the very
thing he wants to discredit in order to arrive at his conclusion.

It would have been perfectly consistent for Hume to argue that although human beings possess an
autonomous faculty of reason, it cannot be used to prove any conclusion beyond the immediate facts
of subjective experience. Induction from past experience to future experiences cannot be rationally
justified. Nor can we justify belief in a necessary connection between an effect and its cause, or in an
external world of objects distinct from our perceptions.

In this scene of desolation, logic and reason remain intact. All human knowledge, on this picture,
consists in knowledge of our immediate experiences, together with knowledge of the relations
between 'ideas', Reason is discredited only when it seeks to establish conclusions that transcend its
(very narrow) limits.

Yet it is clear that Hume wanted to go further, reducing reason and logic to the psychology of the
'association of ideas'. On this 'psychologistic' theory, if we feel ourselves to be rationally persuaded of
the truth of Hume's conclusions, all that is really going on, according to Hume, is a kind of
brainwashing. And that seems fatally to undermine his case. If someone says, 'I am not trying to
persuade you, I am only trying to brainwash you,' Then we are free to walk away.

I think Hume can be defended against this objection. We can summarize the radical Humean position
as the claim that reason is impotent.Let us assume that in order to rationally prove that reason is
impotent it is necessary to assume that reason is not impotent. Then Hume can say:

1. Either reason is impotent or not.

2. If you accept that reason is impotent, then I'm home.

3. If you think that reason is notimpotent then the argument in my book rationally shows that reason
   isimpotent. Then I'm home.

4. So whether or not you accept my claim straight off, reason isimpotent.

— In other words, you can't accuse Hume of relyingon the assumption that reason is not impotent in
order to establish his radical empiricist conclusions. That assumption is merely the discarded premiss
of an argument that proceeds by reductio ad absurdum.

Geoffrey Klempner