To live without philosophizing is in truth the same as keeping the eyes closed without attempting to open them.

Give me extension and motion and I will construct the universe.

Divide each difficulty into as many parts as is feasible and necessary to resolve it.

But possibly I am something more than I suppose myself to be.

And as it is the most generous souls who have most gratitude, it is those who have most pride, and who are most base and infirm, who most allow themselves to be carried away by anger and hatred.

I suppose therefore that all things I see are illusions; I believe that nothing has ever existed of everything my lying memory tells me. I think I have no senses. I believe that body, shape, extension, motion, location are functions. What is there then that can be taken as true? Perhaps only this one thing, that nothing at all is certain.

Let whoever can do so deceive me, he will never bring it about that I am nothing, so long as I continue to think I am something.