The Post Office is issuing four stamps honoring scientists.

One pictures John Von Neumann.

Von Neumann made major contributions to quantum mechanics, he practically invented game theory, but what got him on the stamp was his "invention" of "modern computer design."

It's now obsolete.

Von Neumann architecture required that a computer do one thing, then the next, and on through the program. It led to things like the Cray Supercomputer, a huge, very expensive machine that could do this very, very quickly.

The solution to really amazing speed was to break up the work into parts and run those parts in parallel. This was first done in the 1980s, it was applied to networks in the 1990s, and now it's being applied to chips as "dual-core."

Yet Von Neumann fully deserves a stamp, and specifically for his work on computing. Yes, we've moved on from there, we've built something new and in some ways contradictory on top of it, but that's the point.

Science is the search for what works. What's right can change.

If you don't understand the truth of this, which is true regardless of discipline, then you have no concept of science.

To me it's Von Neumann's greatest lesson.