The Existence of Material Things

Week 11: Meditation VI

The existence of material things

* So: we know about the essences of material things, insofar as these form part of the subject-matter of pure mathematics. But do material things really exist? Descartes' answer is 'Almost certainly' - given that God is no deceiver, and given our natural tendency to believe that the objects of perception are, in general, real. And are material objects actually the way we perceive them to be (are they, e.g., hot, yellow, smelly, etc.)? Here Descartes' answer is less firm. He suggests that material objects may resemble our perceptions of them, but that we have such obscure and indistinct ideas of perceptible properties (see also Meditation II) that it would be unwise to assert of them that they really do exist 'out there' in the world. Perception, he claims, is perfectly decent as a guide to the practical business of getting around, of avoiding harm, seeking nourishment, etc., but shouldn't be mistaken for a source of theoretical knowledge about the world. Such knowledge is the province, purely, of the intellect or understanding. So there's (almost certainly) a material reality out there, a world of 'stuff', as it were, but what we can properly be said to know about it is restricted to its essence - that is, to what is included within the subject-matter of pure mathematics.

* 'Cartesian dualism': according to him, Descartes' essence is that he is a thinking thing - an unextended 'substance' - whereas the material world is an extended 'substance'. The fact the he perceives and imagines indicates, Descartes says, that he is 'closely conjoined to a body' (his), but perception and imagination are, he claims, inessential to him. Therefore his real existence - as an intellect, an understanding, a thing that thinks - is independent of the existence of any material thing (such as, e.g., his body). This picture, together with its attendant difficulties (for example, how interaction between mind and matter might be possible if they have no properties in common), has been Descartes' most enduring - and many would say damaging - legacy to the modern philosophical project.