I have been following this thread with interest and realise that I am coming late to the discussion. However, I think the thread has meandered a bit and it contains some of my pet hates, namely confusion between art and craft, art and technology, art and reputation (historical or otherwise) of the person making it, art and monetary value etc, etc....
The first posters to this thread were absolutely spot on in criticising Alain Briot's essay. I prefer a reductionist approach when considering art which is completely concerned with the classical definition of art 'the expressive arrangement of elements within a medium'. The medium itself may be based on science, technology, craft etc, etc, but that is not important in relation to what is being visualised or heard. Have the elements within that medium been arranged in an expressive way? If the answer is yes, then to that observer, it is art. If enough observers of power, influence and wealth agree that the elements have been arranged expressively, then probably that piece will end up in a gallery/museum/concert hall. It still does not stop another individual coming to their own conclusions about the same piece. For example, I generally find nothing particularly artistic in Renoir's paintings, but I find works by Degas very artistic, because they produce a strong emotional response (no, not tears, you know what I mean).
To those who say this is simply semantics, I totally disagree. Making the distinctions between the words is essential to understanding why a cave painting can be art just as much as a Picasso or whatever. It has nothing to do with science or technology or value etc, but everything to do with the definition above.
Also, I totally agree with those who say that the practice of photography is not science any more than riding a bike is.
BTW if Alain is reading this, can I point you to an excellent essay on photography and art by the British photographer Joe Cornish in this month's Outdoor Photography magazine. Much better written and far easier to understand than David Ward's tortological and turgid prose. 'Art is in the eye of the beholder' and 'one man's art is another man's poison' are as true as they ever were and they apply as much to photography as any other medium, technology and science and craft notwithstanding. As someone else has said, explanation of 'inner vision' and examples that illustrate this together with some historical perspectives and analogies would be of more interest.