Tom,
Assume the universe has an approximately constant curvature on average. General relativity describes a universe homeomorphic to the 3-sphere if and only the curvature is positive. In the Friedmann model, the curvature is either zero or negative. However, you seem to be correct that Einstein believed the universe is finite and unbounded. I copied the following from the Skeptics Stack Exchange:
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Did Einstein say "Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
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The following quotation is commonly attributed to Albert Einstein:
"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."
However, I've been unable to find a reliable source confirming the quote. Can anyone confirm or reject the genuiness of this citation?
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edited Oct 20 '13 at 23:59
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asked Oct 20 '13 at 22:17
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This item at Quote Investigator may be a useful source. - Compro01 Oct 20 '13 at 22:29
@Compro01: I think there is enough there to make that an answer. - Oddthinking笙ヲ Oct 20 '13 at 23:44
As an aside, I'm not sure Einstein believed in an infinite universe as such. Prior to Hubble's results (circa 1929), he seems to have leaned towards a static universe, which would lead then to Olbers' paradox (which was well known) if it was infinite and eternal at the same time. Later on, he seems to have been convinced by the evidence that it is expanding. I'm not sure how an infinite universe can expand, but perhaps that's just me :) A good summary of some of these topics can be found here. - Daniel B Oct 22 '13 at 5:56
Yeah Daniel I agree Einstein held to finite universe till the day he died. It was the common view among Physicist at the time. - Neil Meyer Oct 28 '13 at 10:16
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Unable to determine veracity of quote. It pretty much depends on whether or not you believe a single man's claim about a personal conversation with Einstein.
According to Quote Investigator, the origin of the quotation being attributed to Einstein is the book Gestalt Therapy Verbatim by Frederick S. Perls.
As Albert Einstein once said to me: "Two things are infinite: the universe and human stupidity." But what is much more widespread than the actual stupidity is the playing stupid, turning off your ear, not listening, not seeing.
Further context on the quote is given in another Perls book, In and Out the Garbage Pail.
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."
He also used the quote in a previous book Ego, Hunger, and Aggression: a Revision of Freud's Theory and Method, though did not cite it to Einstein, but rather to "a great astronomer"
Wikiquote lists the quote as "disputed" and also notes similar quotations from various people dating back to 1880.