There has been much written about this. A couple of days ago, though, I came upon a conversation which, for me, shed an entirely different light on the subject. I was listening to an ex-scientist talking about why he changed from science to a new career in the arts. He noted that a scientific discovery, while exciting, is not a unique creative act of an individual. [The operative word here is 'unique'. I'll use it again and again.] What one scientist discovers, another can also discover. In fact, there are many instances of more than one scientist discovering the exact same thing. I write this, btw, as a retired scientist. The artist, though, produces something unique. Each work stands alone. If Van Gogh had not painted 'Starry Night', the same painting would not have been made by another artist. No other author would have written 'The Gathering Storm'. So far, so good? Sorry 'bout being wordy. Just trying to be clear in what I say. Now let's get to photography. It is entirely possible for two photographers to make the same picture. Consider a famous building seen on an overcast day. Two people, not aware of each other's work, can take identical shots of the building and make identical prints. The image in the pictures is not unique. Now here comes what, for me, is the interesting part. There have been some comments over the past few years that 'Photoshop'(r)-ing an image in some way makes the final picture less worthy of consideration as 'art'. Yet, it is this very post-production change which lifts the initial picture from something that may not be unique [someone else could have made the same exposure] to something that is. And the more the changed image deviates from the original, the greater the probability that it will be unique. And I thought, years ago, that I was cheating when I burned in a corner of a print! Shows you how much I knew, way back then.