The size of the problem

Those numbers — 10^120, 10^80 — won't mean anything specific. Nobody really feels the difference between them. The point is just that one is impossibly large, and the other is even more impossibly large.

What matters is the shape of the problem: search works when the space is small. The real world isn't small.

The early researchers had built things that genuinely worked and assumed the rest was a matter of time and computing power. It wasn't. Understanding why they were wrong is most of what the next few slides are about.