Full Idea
The problems of bridging the 'gulf' between mind and matter, in knowledge or in action, are all fictitious problems arising out of the senseless metaphysical conception of mind and matter as 'substances'.
Gist of Idea
The supposed 'gulf' between mind and matter is based on the senseless concept of 'substances'
Source
A.J. Ayer (Language,Truth and Logic [1936], Ch.7)
Book Reference
Ayer,A.J.: 'Language, Truth and Logic' [Penguin 1974], p.164
A Reaction
He is presumably implying that there is only one 'substance', the stuff of physics, thus voting for Spinoza's dual aspect theory. There could still be a 'gulf', between incommensurable properties, or untranslatable levels of description.