The pre-Socratics may be classed as naïve materialists in this sense; though, as at that early period the contrast between matter and spirit had not been' fully realized and matter was credited with properties that belong to life, it is usual to apply the term hylozoism to the earliest stage of Greek metaphysical theory.
Such a motive weighed much with Hobbes and with the French materialists of the 18th century, such as La Mettrie and d'Holbach.
Hobbes, Locke, Hume, Mill and Herbert Spencer are not systematic materialists, but show tendencies towards materialism.
By Descartes the principle was used as an instrument of scepticism, the beneficent scepticism of pulling down medieval philosophy to make room for modern science; by Berkeley it was used to combat the materialists; by Hume in the cause of scepticism once more against the intellectual dogmatists; by Kant to prepare a justification for a noumenal sphere to be apprehended by faith; by J.
Metaphysical materialism is the view that everything known is body or matter; but while according to ancient materialists soul is only another body, according to modern materialists mind without soul is only an attribute or function of body.