Full Idea
My original use of classes was gradually more and more replaced by properties, and in the end disappeared except as a symbolic convenience.
Gist of Idea
I gradually replaced classes with properties, and they ended as a symbolic convenience
Source
Bertrand Russell (My Philosophical Development [1959], Ch.14)
Book Reference
Russell,Bertrand: 'My Philosophical Development' [Routledge 1993], p.117
A Reaction
I wish I knew what properties are. On the whole, though, I agree with this, because it is more naturalistic. We may place things in classes because of their properties, and this means there are natural classes, but classes can't have a life of their own.