The Variable Man (Unabridged)

Philip K. Dick wrote some great Science Fiction and here is an example. Published in 1953, in Space Science Fiction, t his story explores an earth that is rigidly bound both by centuries of single minded focus on war, and on what happens when humans have learned to depend entirely on a mechanical calculator/computer to tell them what to do. There is no room for a factor outside known factors, something to throw all calculations off.
A man from the past. He fixed things-clocks, refrigerators, vidsenders and destinies. But he had no business in the future, where the calculators could not handle him. He was Earth's only hope-and its sure failure!