Descartes:

I think, therefore I am

Supreme metaphysics

At the turn of time

Your shadow

everywhere

Cross-century dust

Because of an idea

Your light shines all the way

In the garden of human spirit

You are an evergreen leaf.

What does "I think therefore I am" mean?

"This is an important proposition of Descartes, which is a truth in his view. Descartes first doubted the truth of everything, such as eating, dressing and so on, which are common to ordinary people. For him, the performance of human activities in thinking can be divided into reality and dreams. However, the authenticity of the two is different. The former is real and the latter is illusory. But for a person, it is impossible for thinking to know clearly whether what he feels is in reality or in a dream. When no one is dreaming, he will think that what he perceives is untrue. He won't think he is dreaming, only when. So Descartes doubts the truth of everything, and this assumption can be established in Descartes' view. So truth and unreality have no absolute meaning, because no one can say for sure that he is not dreaming. However, there is no doubt about one proposition, which I just said, and that is "I think, therefore I am", because no matter in reality or in dreams, one can't deny that one is perceiving and thinking, so as long as one is perceiving and thinking, he must be real, because only the living have this ability.