I see innocence as the lack of mental capacity to understand the nature of our actions. For example, children! I know we can all remember when we were kids. In many occasions, we did things that now may seem ignorant. We were innocent and didn't understand reasons, didn't question anything, our minds were open to endless possibilities. After growing up and experiencing the world, we learned to think more about everything, we questioned things and formed our own definitions, we experience good and bad, we learned that we needed to know more in order to survive in a common society. So we lose our innocence by acquiring knowledge.