The eyes have it

The most obvious thing related to the eyes in Blade Runner is obviously the face that any non-organic lifeform had a strange redish shine to them, especially in the dark. I'm not really sure what this symbolizes because the replicants are supposed to be indistinguishable from humans yet they're eyes often gave them away. But I think the idea that robots or cyborgs are emotionless beings has to do more with our own knowledge about what it means to be human more than something related to the robot itself. In my opinion, humans don't understand humans. Human emotions are so complex, a person often doesn't understand their own emotional reactions to events, much less the emotional reactions of others. Because of this basic lack of understanding about something fundamental to being alive, we know we don't know how to program them into a robot. How little we actually know about emotions, where they come from, why we have them, what they mean, all plays into our assumptions about robots. We KNOW that we make "bad" choices when we are angry or scared or distracted, but how do we KNOW that we don't also make bad choices when we are very happy or proud? In fact, our choices are always influenced by how we FEEL that that exact moment. Are you a little excited to eat Thanksgiving dinner with family? Maybe you don't stop entirely at a stop sign like you otherwise might and boom, now you crash. Or maybe you are stressed about seeing your relatives instead, so you stop extra long at a stop sign and barely avoid that same crash. But you will never know which emotion or combination of emotions actually led to the decision at the stop sign. You will never know why you did what you did and why a crash happened or not. A robot will never be hungry, a robot will never be stressed, a robot will stop every time exactly the same because she is programmed to. The program that humans run on isn't as strict and thus we have emotions and we just don't understand why.