Writing test.

Hello!
I have time now, so I will writing English to improve my sentences.
First, have you thought about your brain?
It is so important because everyone has a different brain.
We sometimes daydream about spiritualism, psychological, abstract things, but actually, our brain causes all of these.
The world is so scientific. However, it may be a bias.
If space aliens disguise themself, we have no way to know it.

Thank you for reading all of my English sentences!