Comment 3 by wisnoskij

Eyes may have evolved separately a number of times but all from a single source.

Life as we know it is all DNA based and came from a single past ancestor and shared the same environment. So I cannot see how anyone can make the statement that eyes will probably show up on all advanced alien lifeforms when all the constants that brought eyes into being will at the very least be slightly different in alien life.

Do you try to excel at being this obtuse? Not all life forms evolved to need eyes, plants operate very well without them for example, but of those life forms that evolved to have a use for them, eyes that is, there are numerous variations...how many types of seeing went extinct in the history of life? A life form on another planet might evolve to "see" in a part of the spectrum "alien" to us....the word "eye" is subjective, an organ for "seeing" with, not much use where there is no light.