Russell asked:

What makes a great philosopher great? Why is Descartes remembered more than Malebranche?

============

You suggest an answer to the first part of this question yourself. A philosopher is called 'great' when
they are remembered more than other philosophers.

You also suggest a test for any definition of greatness. The definition would need to explain, or justify
why Descartes is regarded as one of the great philosophers, but not Malebranche.

My question is, Who decides? Whose memory are we talking about here?

I am tempted to say, it is the students of philosophy, not other academic philosophers whose vote
ultimately matters. The works of a great philosopher are more likely to inspire the student to become
philosophers themselves, and that is what counts. There have been students of philosophy as long as
there have been philosophers. (One of my Pathways students, Graham Nicholson has contributed a
dialogue on the Presocratic philosophers Thales, Anaximander and Anaximenes which wonderfully
captures the spirit of the philosopher-student relationship.)

The works of great philosophers are perennial. They are not subject to the whims of fashion, in the
way that the world of academic philosophy so often seems to be. I don't mean this as a criticism of
academic philosophers. They know only too well the difference between the enthusiasms of the
moment, and works which are destined to have more lasting value.

Let me speculate about Malebranche, about whom I confess I know relatively little. If I get my details
wrong, then just say I am talking about an imaginary philosopher of my own invention. When
Malebranche's works were published, they caused quite a stir. For a while, everyone was talking
about his acute criticisms of Descartes, and debating the pros and cons of his Occasionalist theory of
the relation between mind and body. In time, however, it became apparent that if you wanted to be
stimulated into thinking about the problems of mind and body, you were better of reading Descartes
than Malebranche. The next big thing that came along - the philosophy of Benedict de Spinoza - was
a reaction to Descartes, not Malebranche.

The first time I read Plato, the first time I read Descartes, the first time I read Kant, the first time I read
Wittgenstein are etched on my memory. I can tell you the date, where I was sitting, the other things
that were going on in my life. Try as I might, in my own philosophizing, I cannot get away from the
questions which they first raised.

Geoffrey Klempner