Star Trek: The Next Generation1987

Lt. Commander Data:
I once had what could be considered a crisis of the spirit.

Lieutenant Worf:
You?

Lt. Commander Data:
Yes. The Starfleet officers who first activated me on Omicron Theta told me I was an android - nothing more than a sophisticated machine with human form. However, I realized that if I was simply a machine, I could never be anything else; I could never grow beyond my programming. I found that difficult to accept. So I chose to believe... that I was a person; that I had the potential to be more than a collection of circuits and subprocessors. It is a belief which I still hold.

Lieutenant Worf:
How did you come to your decision?

Lt. Commander Data:
I made... a leap of faith.