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    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeJan 8th 2021
    • (edited Jan 8th 2021)

    I have added this quote attributed to Kazhdan:

    Physics is very interesting: There are many, many interesting theorems. Unfortunately,there are no definitions.

    But does anyone have an authorative reference for this quote?

    It’s attributed this way in

    but neither of these gives any further details (such as: “As overheard over coffee break at ABC.” or “As quoted on XYZ’s webpage.”)

    diff, v5, current

    • CommentRowNumber2.
    • CommentAuthorDavid_Corfield
    • CommentTimeJan 8th 2021

    It doesn’t look like Google knows. Perhaps someone should contact Kazhdan.

    By the way, further down those quotations is one by Rutherford on how he lectured against Kelvin’s estimate of the age of the Earth as 20 million years, via the newly discovered source of energy of radioactivity. I’ve recently learned, however, that the key problem with Kelvin’s calculation was that he relied on a solid earth, and heat flow via conduction, where convection in the mantle is vital.