Over the years, German physicist Albert Einstein — one of the most prominent and revered intellectual and scientific figures in modern history — has been widely quoted and the subject of countless amusing or interesting anecdotes, some of which Snopes has addressed in the past.
One of those is a popular maxim about stupidity, almost universally attributed to Einstein:
"Two things are infinite: The universe and human stupidity; and I'm not sure about the universe."
In recent years, the pithy quotation has appeared in countless memes and social media posts. Its earliest appearances on Twitter and Facebook both came in 2007, and we found examples in newspapers from the 1990s, 1980s, and 1970s.
Einstein may well have written or uttered these words, but definitive proof is not available, and we're issuing a rating of "Unproven." Our suspicion is that Einstein was not the originator of the witticism, for reasons we will explain below. If decisive evidence emerges, we will update this fact check accordingly.
As outlined by the website Quote Investigator, the earliest available instance of this quote can be found in the 1940s. In his 1942 book "Ego, Hunger and Aggression," German psychiatrist Fritz Perls — best known for jointly developing the concept of Gestalt psychotherapy — included a version of the "infinite stupidity" quote. In a section that dealt with the analogy of the human hunger for "mental and emotional food," Perls wrote:
As modern times promote hasty eating to a large extent, it is not surprising to learn that a great astronomer said: "Two things are infinite, as far as we know — the universe and human stupidity." Today we know that this statement is not quite correct. Einstein has proved that the universe is limited.
In this instance, Perls does not attribute the quote to Einstein. He attributes it to an unnamed "great astronomer." He later mentions Einstein, but only as the theoretical physicist who had proved (or more accurately, postulated) that the universe was static, measurable and finite.
Two glaring logical problems stand out. Firstly, if it was Einstein who made the "infinite stupidity" remark, why would Perls not just say so? It would also be odd to describe Einstein as a "great astronomer," even if his work as a physicist did have a significant influence on the field of astronomy.
Secondly, not only did Perls not explicitly cite Einstein as the source of the pithy remark, but he presented him as having directly contradicted the source of the quotation, the "great astronomer." It does not seem plausible that Perls was presenting Einstein as both stating "The universe is infinite" and also proving himself wrong.
And yet, two decades later, Perls repeatedly did just that, attributing the witticism to Einstein himself. In his 1969 autobiography, "In and Out of the Garbage Pail," Perls wrote — perhaps tellingly — of his brush-ins with various celebrities of the mid-20th century:
...My meetings with such famous people as Einstein, Jung...and Freud were casual encounters. They were casual encounters, mostly resulting in nothing but providing some material for boasting and indirectly impressing my audience with my own importance — glamour often overshadowing vision and judgement.
I spent one afternoon with Albert Einstein: unpretentiousness, warmth, some false political predictions. I soon lost my self-consciousness, a rare treat for me at that time. I still love to quote a statement of his "Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe."
In another 1969 book, "Gestalt Therapy Verbatim," Perls again attributed the quip to Einstein, writing:
"As Albert Einstein once said to me: 'Two things are infinite: the universe and the human stupidity.'"
Ultimately, we don't know whether Einstein wrote or uttered the maxim attributed to him by Perls, or whether he communicated it directly to Perls. Our efforts to find an instance of the quotation that was earlier than 1942 and did not involve Einstein were unsuccessful. Hence our rating of "Unproven."
However, it's worth noting that back in 1942, when Perls was closest in time to the occasion on which he first heard or read the remarks, when they were freshest in his mind, he did not attribute them to Einstein, but did mention the physicist as having debunked the concept of an infinite universe and thereby having undercut half of the quip.
In 1969 — a quarter of a century more distant from the first time Perls came across the "infinite stupidity" maxim, he suddenly attributed it to Einstein. To this writer, it seems significantly more plausible that Einstein was not the originator of the remarks, but that over time, Einstein's role in Perls' anecdote shifted in Perls' own recollection and retelling.
Perls — who admitted that his encounters with celebrities served the primary purpose of "providing some material for boasting" — may have found that his "infinite stupidity" line went down better at parties when he inserted the preface "As Albert Einstein once said to me" — even if that attribution did not make sense.