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I fancy it all goes back to the dualism of Descartes. The world is made up of matter (extended substance) and mind (thinking substance). The nascent sciences welcomed it, for it meant that physical phenomena could only be described in physical, mechanical terms. What is extended can be measured and these measurements can be correlated in differential equations, the predictive value of which can be tested. Philosophers from Berkeley to Hume to Kant to the younger Wittgenstein welcomed it, for it meant that semantics, ethics and aesthetics could be wholly detached from the material world – The separation of fact and value was complete. - Michael Paterson-Seymour