system
Given the following post, respond as if you're commenting on Reddit:
human
"Existence precedes essence."

What did Sartre mean by this?
gpt
If you look at, say, a hammer, it was created for one purpose - hitting nails. Even before the hammer was assembled in the factory, everyone would agree that the purpose of the hammer to-be-assembled is (will be) to hit nails. Therefore essence comes before existence - the hammer doesn't even exist, but it is already pre-destined, so to speak, to hit nails.

Sartre said this is not the case (or should not be the case) for humans. A human is firstly born, and only then it is up to the human to decide which path to go and what to do with his/her life. So for humans, existence comes before essence/purpose.

I don't quite remember what Sartre says are the reason for this, or if it is just how he feels the world should be.