Infeld’s essay appeared in a volume in Einstein’s honor entitled Albert Einstein: Philosopher-Scientist. No fewer than six Nobel laureates in science contributed to this book. In his contribution, Georges Lemaître described what he regarded as strong reasons for keeping the cosmological constant in the equations: “The history of science provides many instances of discoveries which have been made for reasons which are no longer considered satisfactory. It may be that the discovery of the cosmological constant [by Einstein] is such a case.” How right he was.

Einstein himself remained unconvinced. In his “Remarks Concerning the Essays Brought Together in This Co-operative Volume,” he repeated his earlier arguments:

The introduction of such a constant implies a considerable renunciation of the logical simplicity of [the] theory, a renunciation which appeared to me unavoidable only so long as one had no reason to doubt the essentially static nature of space.

He continued to say that after Hubble’s discovery of the cosmic expansion and Friedmann’s demonstration that the expansion could be accommodated in the context of the original equations, he found the introduction of lambda “at present [in 1949] unjustified.” Note, by the way, that even though Einstein wrote these comments not long after his correspondence with Gamow, there is still no allusion to “biggest blunder.”

On one hand, you could argue that Einstein was right in refusing to add to his equations a term that was not absolutely required by the observations. On the other, Einstein had already missed one opportunity to predict the cosmic expansion by relying on the lack of evidence for stellar motions. By denouncing the cosmological constant, he missed a second opportunity, this time to predict the accelerating universe! With any ordinary scientist, two such oversights would surely have been regarded as lack of intuition—something we can hardly conclude about Einstein. Einstein’s failures remind us that human logic is not blunder proof, even when exercised by a monumental genius.