"I am an amateur and I intend to stay that way for the rest of my life. I reject all forms of professional cleverness or virtuosity.... As soon as I have found the image that interests me, I leave it to the lens to record it faithfully. Look at reporters, amateurs - both of whose sole aim is to gather a memory or a document; that is.pure photography." Kertz, 1930
Best understood in its historical context, it's a reaction against the dying 'scientist as photographer' idea of his era. It's not really applicable today, since now we're up in arms about accessibility of the medium - and in turn amateurism. His term 'professional cleverness' for example would get you laughed out of many a room. Be careful to whom you recite this quote!
'Cows are very fond of being photographed, and, unlike architecture, don't move.' - Oscar Wilde