A photograph is many things. It can be art. It can be science. It can be beautiful, ugly, strange, mediocre, brilliant.
To me a photograph is an infinite space, filled with infinite planes of focus. Each plane of focus is an inverted miniature of a conjugate plane on the other side of the lens. When one of those image planes coincides with the sensor then that plane looks sharp, and the rest looks blurry. Changing focus is merely the process of shifting the sensor through those infinite miniature planes.