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    • CommentRowNumber1.
    • CommentAuthortrent
    • CommentTimeApr 18th 2015
    • (edited Apr 18th 2015)

    I added a blurb from and link to Connes most recent lecture (Temps et aléa du quantique (english)) on the time page. (Added both for its innate interest and to help understand the transit between mathematics and philosophical intuition).

    When I was in preparatory school, my teacher asked me (…) “what is a variable?”. I reflected and reflected, and after a while, I said “time”. (…) The topic of my talk is that I believe we are all used, because of our constitution and so on, to attribute variability to the passing of time. The thesis which I will propose and try to back with mathematical results is the following: I believe that the true variability is quantum, and that the true variability is the fact that when you take a quantum observable it doesn’t have a single value, but it has many possible values which are given by the spectrum of the operator, plus the fact that discrete variables cannot coexist with continuous variables without the quantum formalism. I will explain how time emerges from these facts. I have never tried to explain this idea, I know it’s difficult, and its difficult because in my mind it is backed up by an intuition which comes from many years of work, and this is the most difficult thing to transmit. (…) How to explain this? (…) The answer I believe comes from Von Neumann (suitably implemented and very much ameliorated). (…) In the 40’s and 50’s Von Neumann was asking what does it mean to have a subsystem? What does it mean that somehow, the Hilbert space in which you work is a Hilbert space in which you have partial knowledge of things because the system is a composite system and there is a part of the system which you know and a part which you ignore? What Von Neumann was trying to understand was factorizations. (gives lecture on factorizations…) By the way, I should say that this is why I spent many years studying Noncommutative Geometry: the simplest geometric origin of Von Neumann factorization is foliations. If you take the simplest foliation (well, I don’t know if it’s the simplest), the [???] foliation of the sphere bundle of a Riemann surface, you get the most exotic factorization of Von Neumann? (type III1).

    • CommentRowNumber2.
    • CommentAuthorDavidRoberts
    • CommentTimeApr 18th 2015

    Thanks, Trent! I thought that lecture was in French, so I wasn’t going to watch it. But it looks pretty good from what I saw already. The comments about Newton-style infinitesimals are interesting…

    • CommentRowNumber3.
    • CommentAuthorTim_Porter
    • CommentTimeApr 18th 2015

    What is the origin of the English text?

    • CommentRowNumber4.
    • CommentAuthortrent
    • CommentTimeApr 18th 2015

    the text is composed of excerpts from 10:45 - 17something (w/ some paraphrasing) + the final comment starting at 57:52. despite the french title and youtube blurb, the lecture was delivered in english.

    • CommentRowNumber5.
    • CommentAuthorDavid_Corfield
    • CommentTimeSep 23rd 2016

    Since we had a talk on the philosophy of time here yesterday, I thought I’d add something brief on this at time.

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