Premise: John von Neumann's Universal Constructor is a self-replicating machine in a cellular automata (CA) environment. It was designed in the 1940s, without the use of a computer. The fundamental details of the machine were published in von Neumann's book "Theory of Self-Reproducing Automata", completed in 1966 by Arthur W. Burks after von Neumann's death.
Hypothesis: Neumann never used a computer.