"I do not maintain positively that space-time is discrete, but only that it cannot be shown not to be."

"1) I do not feel any difficulty in the concept of infinite continuity. I only think that the opposite hypothesis is tenable and interesting. 2) I have written nothing on this subject since Human Knowledge, but as regards supporters, I think you might find it interesting to write to H.W. Poole [address] who professes to have a proof that space-time must be discontinuous. He sent me his proof, but I was unable to estimate its validity. 3) I have never discussed Whitehead's system of extensive abstraction. He and I, after many years of friendly collaboration, came to a profound disagreement and neither of us cared to discuss our disagreements in public. I must confess that I have forgotten the gist of his system of extensive abstraction."