Discourse on Method and Meditations on First Philosophy

Why does Descartes believe that a triangle is an adequate metaphor to show the existence of the idea of God and the soul?

Why does Descartes privilege ideas that are clear and distinct as opposed to confused and obscure?

Why does Descartes think that we can only be sure that we exist as thinking things, as opposed to embodied beings?

What does Descartes identify as the source of our error when attempting to conceive of the existence of the mind, the soul, and of God?

How does Descartes envision his philosophy in relation to science and medicine, and why does he believe that his discoveries will pave the way for a practical, as opposed to purely speculative, philosophy?

How does Descartes prove that he exists and can be certain of it beyond all reasonable doubt?

How does Descartes prove the existence of God? Does Descartes find it problematic that there can never be a corporeal object that corresponds to the idea of God? Why or why not?

According to Descartes, what role(s) do the intellect and the will play regarding the source of truth and error in human knowledge? What does Descartes propose as a solution for mitigating the number of errors made by the human mind?