René descartes scientific revolution

Accordingly, a mode requires a substance to exist and not just the concurrence of God. Being sphere shaped is a mode of an extended substance. For example, a sphere requires an object extended in three dimensions in order to exist: an unextended sphere cannot be conceived without contradiction. But a substance can be understood to exist alone without requiring any other creature to exist.

For example, a stone can exist all by itself.

René descartes cartesian dualism

That is, its existence is not dependent upon the existence of minds or other bodies; and, a stone can exist without being any particular size or shape. Hence, the thesis that mind and body are really distinct just means that each could exist all by itself without any other creature, including each other, if God chose to do it.

However, this does not mean that these substances do exist separately. Whether or not they actually exist apart is another issue entirely. For Descartes the payoff is twofold. This section investigates both of these motivating factors. Descartes goes on to explain how, because of this, these people will not pursue moral virtue without the prospect of an afterlife with rewards for virtue and punishments for vice.

But, since all the arguments in the Meditations —including the real distinction arguments— are for Descartes absolutely certain on a par with geometrical demonstrations, he believes that these people will be obliged to accept them.

René descartes introduction

Hence, irreligious people will be forced to believe in the prospect of an afterlife. He stops short of demonstrating that the soul is actually immortal. Yet, even though the real distinction argument does not go this far, it does, according to Descartes, provide a sufficient foundation for religion, since the hope for an afterlife now has a rational basis and is no longer a mere article of faith.

Notwithstanding this convoluted array of positions, Descartes understood one thesis to stand at the heart of the entire tradition: the doctrine that everything ultimately behaved for the sake of some end or goal.