"Materialistic monism is nowadays the working hypothesis of every scientific explorer in every department, whatever other beliefs or denials he may, more or less explicitly and more or less consistently, superadd. Materialistic monism only becomes false when put forward as a complete philosophy of the universe, because it leaves out of sight the conditions of human knowledge, which the special sciences may conveniently disregard, but which a candid philosophy cannot ignore."

"The legitimate materialism of the sciences simply means temporary and convenient abstraction from the cognitive conditions under which there are 'facts' or 'objects' for us at all; it is 'dogmatic materialism' which is metaphysics of the bad sort."

D. G. Ritchie.

"Our metaphysics is really like many other sciences—only on the threshold of genuine knowledge: God knows if it will ever get further. It is not hard to see its weakness in much that it undertakes. Prejudice is often found to be the mainstay of its proofs. For this nothing is to blame but the ruling passion of those who would fain extend human knowledge. They are anxious to have a grand philosophy: but the desirable thing is, that it should also be a sound one."

Kant.