The Alan Sondheim Mail Archive

Illiterate notes on Roger Penrose, The Road to Reality, A Complete Guide 
to the Laws of the Universe -

I've been reading this book slowly - which it demands; it's 1100 pages 
roughly. At this point, I'm almost finished - I want to recommend the book 
absolutely to anyone interested in contemporary pictures of the world. I 
wrote a comment on a science blog to this effect -

"The Road to Reality fascinates me for a number of reasons. It doesn't 
hold back on the mathematics, and gives enough bibliographic materials 
(online and offline) for background information. It also has an odd 
development of opinion; string theory is presented, partly in relation to 
Penrose's critical technical analysis, but also in relation to its "hip" 
content, picked up by the media. This is where Penrose's discussion of 
fashion in physics is critical - a discussion that should be applied to 
any number of fields (philosophy or sociology for two examples - where are 
Sartre and Parsons now?). The reader observes the working physicist 
throughout these sections, ignoring the cant and carefully evaluating 
claims - not only of string theory, for example, but of dim > 4 theories 
in general. There's another important point, I think - too often "popular" 
accounts gloss over the mathematics. For me the result has always been 
distorted notions that all-too-quickly are related to Buddhism, holisms, 
etc. etc. Penrose gives the complexity, if not the details, of the 
mathematics at work. It's an extremely hard read, but I couldn't put the 
book down; for once I felt that I was actually learning something about 
the working of physics _qua_ physics... - "


I want to add that a number of the models presented may also be useful, 
even for a non-mathematician for example, in thinking through the 
analog/digital distinction - which I think is related to the U -> R 
collapse that forms the central portion of the book (i.e. the wave 
equation doewn to a specific eigenvalue vis-a-vis measure- ment). Since 
I'm not a physicist, I'm not sure how this applies specifically to the 
Aristotelian logic of everyday life (i.e. without employing a beam- 
splitter or other sub-atomic particle/photon apparatus), but I have some 

In any case, the work is brilliant. Hint - don't skip the math even if it 
proves almost unreadable (sections were for me); just go back and reread, 
look up the concepts elsewhere. As I mention above, physics without math 
is _always_ distorted; equations, theories, etc. just don't translate that 
easily. What happens is that equations -> metaphor as an explanatory mode; 
then metaphor1 -> metaphor2, etc. - and the "sphere of as-if" expands - as 
if, in other words, physics or at least physical theory or at least theory 
were _being done._ The concepts become a kind of legitimation-apparatus 
(which is what Sokal was after, I think), increasingly removed from faulty 
translation inthe first place. Reading Penrose is sobering in this regard, 
but incredibly illuminating - and as I indicate above, the gift to the 
reader is not only the (mathematical) physics, but also the _workings_ of 
physics and physicists; for example, on p. 952, the value of something 
called the "Barbero-Immirzi parameter" is given - and a footnote tells us 
that the value was found incorrect as the book was going to press. Physics 
is often incredibly generous in this regard; Gerald Feinberg, one of the 
"inventors" of the tachyon concept, once told me he wouldn't be perturbed 
if tachyons were never found (they haven't been as yet). Popper's falsifi- 
cation comes to mind, and Penrose critiques his work as well (pp. 1020- 
1024). Read on...

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