system
Given the following post, respond as if you're commenting on Reddit:
human
Why or how did we evolve eyes?

Sorry I didn't know what category to put this is but it is something that has been on my mind for a while. So my question to anyone with an answer is "why or how do we evolve eyes?" The eye is so incredibly advance that a simple person like me can hardly grasp all the technical parts of it, however I am not necessarily looking for the mechanical or mathematical way we see. 
To my understanding, evolution, is survival of the fittest. Small mutations that give an advantage over the original will thrive and      continue to reproduce. However, if we (talking as if we were still single cell amiba) were blind, no eyeballs to speak of, then we would not know that a seeing world would even exist. So where would the evolution of the eye even begin? Yes, seeing is a huge advantage to being blind, but how would something so complex just happen without our bodies being able to recognize we are blind?
gpt
Basically, because it didn't happen like you think it did.

Eyes have arisen several times throughout the history of animals, and each time it starts off as very simple photoreceptive cells - cells that can tell if it's light or dark. This can be useful for a number of reasons - it can help determine depth in water, or if you've stumbled into a cave, or if something is moving between you and the light source.

And, as with all things, over millions of years and millions of generations, the complex organs we call our eyes developed. Each and every time, the slightly more complex eye provided a slight advantage to those that had them.

One more thing:

"how would something so complex just happen *without our bodies being able to recognize we are blind*?"

DNA lacks conscious thought. DNA does not know anything, it does not recognize anything, and it certainly does not plan anything. It just exists. It's very easy to anthropomorphize evolution, to see it as a plan or process, with some kind of intent or goal. Humans are very good at projecting our own traits onto other things. But that is not how evolution works - it just is.