I don't know why you call it Darwinian evolution, is beyond me. Darwin may have first discovered it and submitted it but that is 1000's if sciences in all disciplines that confirm its validity, that aside.
The Eye yes evolved in steps with a mutation that helped it detects light, and so on and so forth until we have the Eyes of today. You must remember all life came from very simple organisms and that this mutation would happen and if it was nutrel or benefited the organism in its environment it stayed and if it was harmful it was removed. So the Theory can be applied to anything that changes over time even smart phones have 'evolved' (though this was purely human refinement) I think you miss the point it happens very slowly over a long period of time.
And you starting at the wrong end. Of course it would be impossible for that to be created from random if it suddenly popped into existence. but if you start with the building blocks you can get very, almost impossably complex structures.
Evolution in animals is almost like LEGO, you start with one block and you slowly add and shape and work out the most effance design purly though trial and error but you really have no goal so the possibilities are endless.
So back to the eye, there were no need for eyes but as time when on in one environment (one with light) creaters that could see would have a advantage over the others in the day time. you have to look at it small and simple to big and complexe or yes it would not make sence.
And who every said that for something to happen you needed a goal?
It is all down to what would benefit the organism the most and a light sensing dot on a ammba or something like that could be the diffenance between when to come out to eat and when photosynaise (not saying there is a creature like that but it is possible).
"Religion is regarded by the common people as true, by the wise as false, and by the rulers as useful" - Edward Gibbon (Offen misattributed to Lucius Annaeus Seneca or Seneca the Younger) (Thanks to apophenia for the correction)
'I am driven by two main philosophies:
Know more about the world than I knew yesterday and lessen the suffering of others. You'd be surprised how far that gets you' - Neil deGrasse Tyson
"Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it." - Mark Twain
'I am driven by two main philosophies:
Know more about the world than I knew yesterday and lessen the suffering of others. You'd be surprised how far that gets you' - Neil deGrasse Tyson
"Sometimes I wonder whether the world is being run by smart people who are putting us on or by imbeciles who really mean it." - Mark Twain