This gallery on the Beast is trying to make the argument that Van Gough’s lack of focus in his later works represent his “slipping” mental state towards the end of his life. I can’t really get on board with the argument, I thought part of being an artist is the ability to recognize significance in the ordinary and unspectacular.
http://www.thedailybeast.com/newsweek/galleries/2012/01/29/van-gogh-close-ups-at-the-philadelphia-museum-of-art-photos.html#slide1