Theorists have to justify their existence it seems. Liz Wells writes at the begining of her book “Photography A critical Introduction” that “Theory informs practice!” yet without practice there would be no theory. Initial photographic theory was more concerned with chemistry quite different to the conceptual concerns of present day theory. In fact, when one is talking about photographic theory this is usually understood in terms of aesthetics rather than any scientific concern. A literature has grown up around photography that attempts to discover it’s nature and I have to say that in spite of it’s academic approach, I find it fascinating !