[FOM] The gold standard and FLT

Arnon Avron aa at tau.ac.il
Wed Jan 10 17:12:37 EST 2018


In reply to my words "standard, eternal criteria of mathematics"
(that meant, if it was not clear, the standard, eternal criteria of
a rigorous, acceptable proof in mathematics), David Brenton wrote:

> I think you're getting this backwards. Math has not always been 
> this "paradise of rigor", which has just stopped being so in recent times. 
> On the contrary, for the longest time (with possibly the only 
> exception of Euclid's elements), mathematics was an activity where 
> the primary objective was to obtain results, rather than to be 
> rigorous. Looking at most proofs from two or three centuries ago, 
> they look much more like the kind of intuitive arguments that physicists 
> do than like modern times proofs. The whole concern about foundational 
> issues is relatively recent, its embryo probably first arose about 
> halfway through the XIX century, and it only took full force in 
> the early XX century. Considering that math has been around for 
> millennia, I'd say that being careful about axiom systems, and 
> what assumptions are being made, and about completely rigorous 
> proofs, and the like, is more the exception, rather than the rule.

And Timothy  Chow wrote:
 
> Idealism is one thing, but historical inaccuracy is another.
> "Making explicit in a very precise way what are the assumptions that
> underlie the alleged proof" is almost never done in mathematics.
> 
> For centuries, Euclid was the gold standard.  Today, we don't think
> that Euclid "made explicit in a very precise way" what all the
> assumptions were.
> 
> If we look at mathematical practice across all fields and all of
> history, your "standard, eternal criteria" are far from being
> either.

I was really amazed to read this kind of defense of the
current alleged proof, and especially of the attitude, of those who
claim to have proved FLT. I do wonder if those algebraic geometers
would be happy with the comparison made in these two messages of 
their activity and proofs with those of  the mathematicians 
in the 17th and 18th 0...  

 I also wonder, in view of what is described in these messages,
why we torture our students and ourselves by teaching
them what a rigorous proof should look like, and in 
particular point out to them as severe mistakes  claims made
in their "proofs" that are not justified  by the collection of the
assumptions of the theorem they try to prove and 
theorems that have already been proved before. What for? After all,
one needs not justify, or even make explicit, all the
assumptions one uses. Right?

  Anyway, both Tim and David are confusing, in my opinion,
the norms of some area with the actual activity of the people
involved in that area. Thus many  religious people do sins.
Does this mean that they do not know what are the norms
in their religion and what is expected of them? 

  Despite what Tim and David note, mathematicians have had
a rather clear standard of what a rigorous proof is since
the time of Euclid. (And if they try to forget it,
people like Berkeley were there to remind them.) 
Yes. There were periods in which the will to make rapid progress 
in science caused mathematicians to neglect the old mathematical
norm of rigor. This does not mean that the mathematicians
at that time were not aware that they are not following
the standard eternal criteria. On the contrary: they felt
the need to justify this fact by claims like "for
rigor we have no time". (Sorry I do not remember now who
said this, and what were his exact words.) And of course,
At that glorious period really great mathematicians 
were falling in traps like "proving" that 1-1+1-1+1...=1/2
Luckily, we have made some progress since those days. Are we
starting to go back? I am afraid that we are beginning to.

  One more remark about Euclid. Tim emphasizes that
"Today, we don't think  that Euclid `made explicit in a 
very precise way' what all the  assumptions were." 
Absolutely true.  We have made indeed a great (temporary?) progress
since Euclid's time, and our  criteria
of rigor are (temporarily?) higher. But is there anybody who
infers from this, or thinks, that Euclid did not *try*
to make all his assumptions explicit? The crucial thing
is not whether Euclid succeeded in fully following 
the general principles he forever set for mathematics,
but that he did set those principles, and was doing
his best to follow them. In contrast
(according to what I read here), the experts about the
alleged proof of FLT do not bother at all to make
their assumptions explicit!

  Some years ago I predicted that all the great known 
problems of mathematics will be solved in the next few 
decades, because all is needed for this is to make "proofs"
very long and complicated on one hand (so that
nobody can really check them),  and not care 
too much about rigor on the other... Isn't this wonderful?

Arnon



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