It was a purely philosophical experience in which I lost all believe into gods and artificial distinctions between humans and other animals. I cannot come with any reason, why eating humans must be wrong, but eating a cow should be okay. So I decided, that harming either of them must be wrong and my ability for compassion had to extent further than my own species. There is no God to tell my how to be good. I have to decide for myself and I decided to inflict less harm on my fellow earthlings.

Also, there is no free will.