The issue between them is: How much can we know about the universe?
"I am a mysterian," says Gardner, in his new (posthumously published autobiography) . Mysterians, he writes, believe that some things — how life began, the nature of time, what consciousness is, whether there is free will — are so inherently complex that they will forever elude human understanding. Not only does "no philosopher or scientist living today [have] the foggiest notion" of how mind or time or consciousness work, "we believe" he wrote, "it is the height of hubris" to suppose those things will ever be understood completely.
Gardner allows that humans have wonderful brains, that we can invent thinking machines, microscopes and any number of intelligence-enhancers, but he says there are still limits, hard limits.