I don't believe that old age is the age of wisdom, but a progressive advance towards stupidity — David Mo

And thus you pave the road ahead - a passage fraught with loathe and dread. :groan:

Is quantum theory the "set theory" of physics? Weird at first but providing a foundation? :chin:

Thus for any finite sequence, it repeats, and repeats IT. — tim wood

This idea appears to be connected to normal numbers, and I don't think pi has been proven to be such.

It is a curse on some levels alright, including health and sex wise, and a blessing on others, such as wisdom, I think. — Olivier5

From the perspective of an 83 year-old this seems a bit naive. Especially the wisdom part. A lot depends on one's health, and if that remains fairly good sex may be possible and can be enjoyable. For men, keeping testosterone levels up helps considerably.

As you age your attitudes change, and it's not necessarily a downward spiral. I was an active rock climber from age 16 to age 70, and as a youngster I would think, as other climbers do, that I wanted to continue it all my life. But at 70 I was happy to leave it behind and turn to other activities I had learned to enjoy. What we might consider at age 20 to be indispensable to life turns out not to be.

But it is important in old age to have ongoing projects. I have two elderly friends, one a year older than me and the other ten years younger. Each has been working on a book for a decade or more. They keep revising and changing material, feeling that each such action is an improvement. I'm guessing they may never actually complete their projects, but that's not the point.

Speculating about old age when young is an entertaining diversion, but not very productive.

From the perspective of an elderly mathematician jigsaws are like doing a problem in a textbook (I never liked that) - difficult, but uninspiring, they've been solved hundreds of times before - while an uninhibited foray in which creativity is paramount is far more satisfying. Avoid those "jigsaw puzzles" that go round and round in philosophical arguments conducted thousands of times already. The probability of making a breakthrough is very, very small even if you are an intellect to be reckoned with. Instead, be creative and move into relatively unexplored territory. There you might succeed and produce something unique, even though it might be of low general interest. :cool:

My best friend for over forty years was once a physics major, but he switched to math after taking an introductory course in quantum theory. He became a highly regarded math professor. My father had a masters in math, then took a course in topology one summer in the 1930s at the U of Michigan. He then left math to become a business statistician.

There seems to be a point in an academic progression at which a student may get into a course in his area that is an abrupt excursion into something that seems weird and unlike anything he has encountered before. If he is fortunate and has a really good prof he may become enthusiastic and proceed, or, more likely, he may have an indifferent prof and exit the discipline. My own experience was a beginning grad course in set theory. It could have come close to leveraging me out of math, but the young, energetic prof made it both interesting and pleasantly challenging. I never returned to the subject, but I stayed in the discipline.

I had a year of physics, planning to become a physicist - but reading about quantum theory showed me the error of my thinking! Hats off to Kenosha Kid. :up:

Well done! :cool:

I chose a name coming into the forum that represents me - it is my name, and I’m not trying to project anything other than who I really am. — Roy Davies

Ditto, although I use a simple contraction I like. My moniker was well known on a popular climbing forum before it vanished. My feeling is that we all reveal who we are, or provide easy clues one might follow to find out. Why hide behind an obscure avatar?

I wonder what you mean when you say "an object feels the effect of...", but does not show any physical change. — Metaphysician Undercover

Those were Dr. Patel's words, not mine.

Do you think that an inanimate object has the will power to resist — Metaphysician Undercover

How amusing. Patel does have a way with words. I know so little of the subject; nevertheless, a particle having will power is a challenging conjecture. You should follow up on this. :cool:

There is a shortest period of time, Planck time, during which something can happen. — Metaphysician Undercover

Here's what Lalit Patel, PhD physics had to say in 2017 on Quora:

"Planck time is an extremely small time duration, which current technologies are not able to access.

I guess that the following events can occur in the duration of Planck time.

1. An object feels the effect of gravitational force transmitted from an object.
2. A particle feels the effect of electromagnetic, weak, or strong force transmitted from a particle.
3. A photon feels the presence of a surface and decides to retract. (A photon impinging on a surface gets converted into another photon.)
4. A typical string of the string theory completes one oscillation cycle."

Am I mistaken that what could happen in Planck time is more a matter of metaphysics than physics itself? If this is a settled issue please provide links. I have very little knowledge of quantum physics.

There is a shortest period of time, Planck time, during which something can happen. — Metaphysician Undercover

And not merely be non-measurable? Very well. :sad:

There is a shortest period of time,Planck time, during which something can happen. So there is a state at t1, then a state at t2, and nothing can happen between t1 and t2 because it is too short of a period of time. — Metaphysician Undercover

A photon travels at the speed of light over a Planck length during this "time". Therefore, something happens as time progresses.

A fact that few take into account because few know it: there are more mentally ill people among celebrated scientists than in the general population — bcccampello

I don't think MU is a celebrated scientist. But I could be wrong. :wink:

And thus on that day the Lord created aman — Kenosha Kid

Whoa, not so fast! Where is the link between complex numbers and the existence of man?

Inquiring minds want to know. :chin:

A matter of notation and mathematical clarity. See definition 7.1

https://www.math.uchicago.edu/~may/VIGRE/VIGRE2011/REUPapers/Lian.pdf

Not a big deal. You are to be applauded for wading into this.

x=(a,b) and y=(c,d) are ordered pairs of integers, not integers themselves. So x and y belong to the Cartesian product of the integers. You're defining an inequality of ordered pairs in terms of an inequality of integers.

Calling fishfry! :cool:

Christ, I think it'll take me longer to debug the mathjax than it did to write the comment. — Kenosha Kid

MathType works well - it's WYSIWYG - using the Wikipedia cut and paste option. You only have to replace <math> with [....]. Just a thought.

∀x=(a,b),y=(c,d)∈Z
y>x↔c+b>a+d — Kenosha Kid

$\left( c,d \right)\in Z'=N\times N$

Trump's male picks all seem to be spineless, vicious, or both — tim wood

I'm curious about Neil Gorsuch in this regard. Is he really that bad?

The point of that thread is to illustrate specifically how, in a very distant way, we ourselves can be said to be made of empty sets. — Pfhorrest

Some time back on another thread I mentioned being curious about the process of going from the empty set to the fundamental theorem of calculus, step by step. I had done this sort of thing sixty years ago when a professor had us reach the exponential function this way. Your proposal is much more challenging. :smile:

Here the case of climate change is especially relevant. This is not an issue about abortion, guns, or immigration -- this is an issue that is settled — Xtrix

True enough. What is not settled is whether it can be altered significantly. Especially with not all nations on board. Don't buy beachfront property in Miami.

This is a very ambitious thread. But probably no more than the first 900 pages of Penrose's The Road to Reality. I may not live long enough to see its completion, but you guys are younger, so there is hope. :worry:

I shall try and get the field of real numbers with its order defined in that time. — fdrake

Look forward to this! Next, well-order an uncountable set of reals. :cool: :up:

I'm picking up tiny tidbits of math here that relate to topics I am familiar with, but it's all pretty fuzzy. For instance, $SU(2)\subset GL(2,\mathbb{C})$, and the matrix multiplication in SU(2) corresponds to compositions of bilinear transforms - as I mentioned before. To elaborate:

$\left [\begin{matrix}{{\alpha }_{k}} & -{{{\bar{\beta }}}_{k}} \\{{\beta }_{k}} & {{{\bar{\alpha }}}_{k}} \\\end{matrix} \right]$

Corresponds to

${{t}_{k}}(z)=\frac{{{\alpha }_{k}}z-{{{\bar{\beta }}}_{k}}}{{{\beta }_{k}}z+{{{\bar{\alpha }}}_{k}}}$

And multiplication is the following

${{t}_{k}}({{t}_{k+1}}(z))=\frac{{{\alpha }_{k}}{{t}_{k+1}}-{{{\bar{\beta }}}_{k}}}{{{\beta }_{k}}{{t}_{k+1}}+{{{\bar{\alpha }}}_{k}}}$

edit: But the matrix represents a quaternion, primarily. I.e., extending the complex numbers to a higher dimension. In the above, alpha=a+bi and beta=-c+di to give the quaternion a+bi+cj+dk.
SU(2) seems to associate with spin. The multiplication of two such 2X2 matrices may give the Hamiltonian product, or maybe not. Too much work involved.

GL(2,C) is a Lie group corresponding to the group of linear fractional transformations (LFTs). When you matrix multiply two 2X2 such creatures it's the same as composing one transformation with the other. Each such transformation maps Circles to Circles in C (a line is construed to be an infinite circle), so these transformations preserve those geometric objects in the complex plane. Otherwise, in the complex plane simple translations and rotations preserve geometric figures. I've done lots of exploring of the properties of LFTs, but all of it as analytic or meromorphic functions from an analytic rather than an algebraic perspective. Very old fashioned
of me.

@fdrake is far more up to date and knowledgeable.

Better simply to eviscerate the "theory". :yikes:

Different coordinate systems can map different numbers to different points without changing any features of the resulting geometric object — Pfhorrest

You probably need to qualify this. Take the circle x^2+y^2=1 in the standard Euclidean plane and lengthen the scale on the x-axis, so that the circle becomes an ellipse. That's a "different coordinate system".

Amazing how the physicists can use those groups. :cool:

Maybe Philosophy will always only describe the structure of reality without actually participating — Noble Dust

I see occasionally on this forum discussions that might go on for pages about subjects that are actually practices and not merely ideas. When that is the case first hand knowledge seems to me to be a prerequisite for philosophizing. But I may be in the minority here.

↪jgill
The Lounge isn't supposed to be purely philosophical. You can start a thread solely about kittens here, according to the description. — Professor Death

I think I made that post when the thread was on the main page. More appropriate here.

And it's not a matter for philosophical debate — tim wood

Then it should appear in a different forum.

So the speculative metaphysics I had in mind is a physics where spin is the basic notion — apokrisis

Thanks for the clarification.

I'm a retired mathematician with little knowledge of philosophy, so I mostly read posts. The writing on this forum is at times excellent, and the ideas expressed - well, sometimes consistent with the quality of writing. Oddly enough I have learned a bit more about mathematics here, as well as physics. But I admit I get snookered by convincing posts in the latter subject when metaphysics seeps into the discussion. :smile:

I am basically asking if we gain any real virtues with age that aren't the direct result of our own decline? — TiredThinker

In my 8+ decades I have seen and experienced much, and that accumulated history perhaps gives me a different if not better perspective on current events. I have become more tolerant and far less impulsive.

And since Frank Apisa was excommunicated from the forum I feel somewhat alone. That's not bad really, since much of my avocational career as a rock climber was going solo. :cool:

Take the law of universal gravitation: G(m1*m2)/(r^2) ... For instance, it could've been G(m1/m2)*r^3 — TheMadFool

How intriguing . . . please explain.

Probably. But take for example the element of the power set of N: {2,6,7}. This could be interpreted as guest(2)->room(6), guest(6)->room(7),guest(7)->room(2). Kind of silly, I guess.

Wiki, Sartre's The Look: "The mere possible presence of another person causes one to look at oneself as an object and see one's world as it appears to the other. This is not done from a specific location outside oneself, but is non-positional. This is a recognition of the subjectivity in others."

This is deeper than simply not caring what others think. As a former outdoors athlete I experienced this many times. And it wasn't related to safety or competition issues. The mere presence of another changes the experience.

A highly colored painting turned to pure white leaves nothing but an empty canvas.

I don't remember ever coming across a claim that there's an operation we can perform on the naturals that can yield a greater infinity than it. — TheMadFool

The power set of the naturals.

One long, continuous paragraph might be a little much to process, whereas ten second parts separated by pauses allowing the listener to digest a sequence of related ideas might work better.

I wonder how the kids of today are going to do when the have to sit through a 90 minute university lecture. — Sir2u

Times are changing. Ninety minute lectures may fade away. I hope so.

Does this attitude/behavior reveal something about the human psyche? — TheMadFool

It might reveal more about what you were saying during that 59 seconds. Just a thought.