Having to figure things out by yourself is extraordinarily inefficient (plus, risky). The primary benefit of civilization is curriculum optimization: getting you to the right destination while expending the least amount of experience. Civilization is integral to human cognition.

To caricature, you could say that the human brain is merely a short-lived mirror of what constitutes the main body of human cognition: the thought patterns, behaviors, and systems we've collectively evolved over thousands of years.

Your mind reflects the civilization that shaped it -- it wouldn't amount to much without it.

It's mostly the process of civilization, not you, that really thinks (in the sense of producing solutions to human problems). It then passes on the solutions to you. There is rather little that you could be said to have figured out on your own within your own lifetime.