Finally, there is the truly dumbfounding question of why Pauling ignored some basic rules of chemistry in his model, such as those concerning the acidity of DNA. The world’s most celebrated chemist fumbling in some elementary chemistry?

I asked molecular biologist Matthew Meselson about his thoughts on this aspect of the blunder. Meselson, Pauling’s graduate student at the time, conjectured that Pauling might have considered the problem and had convinced himself that it could somehow be overcome. This would certainly be consistent with Pauling’s general frame of mind throughout the entire DNA model-building episode. His thought process must have been something like this: He had a highly successful model for proteins, which consisted of a helical strand with side chains on the outside. He therefore thought that the model for DNA would be that of interwoven strands, also with side chains (the bases, in this case) on the outside. This created a packing problem along the axis, but all the rest of the characteristics, in Pauling’s mind, were in some sense details to be sorted out later. Again, his previous success with the alpha-helix apparently had a blinding effect. Unfortunately, as we know only too well, the devil is often in precisely those details.

In my conversation with Jack Dunitz, he recalled that Pauling had once told him something that summarized beautifully his attitude toward scientific research:

Jack, if you think you have a good idea, publish it! Don’t be afraid to make a mistake. Mistakes do no harm in science because there are lots of smart people out there who will immediately spot a mistake and correct it. You can only make a fool of yourself and that does no harm, except to your pride. If it happens to be a good idea, however, and you don’t publish it, science may suffer a loss.

Dunitz added that indeed the three-stranded structure did no harm, except to Pauling’s reputation. He commented further that Pauling had made enough major contributions that we should simply forgive and forget. I must say that I fully agree with the “forgive” part, but I actually think that we should not forget. As I have attempted to show, there are many insights that can be gained from analyzing such blunders by brilliant individuals.