Is There Perfection in Physical Laws?

[Avichal]

The laws 'behave perfectly'...but that doesn't mean they are absolutely precise representations of nature.

Likewise, quantum mechanics, and GR.
And quantum mechanics was 'updated' so the Standard Model, another very accurate model, utilizes relativistic quantum mechanics.

Really? Even the more modern theories are not accurate? Have we found some error in measurements or is it your own personal view?

 

[Delta Kilo]

Penrose goes on to say in ROAD TO REALITY

You have to be careful with this book, it's heavy :)

While the math part seems to be rock solid, when it comes to physics, especially QM and beyond, there are quite a few disclaimers stating that this or that bit is his personal view different from the mainstream. For example, the bit you quoted about classical, reduction and quantum is one of those. To be fair, every now and then he does the reverse and presents the mainstream view while making it clear he himself does not share it.

I mean the book is great, really great, but I wouldn't take quotes from it as a gospel without careful examination of the context.

 

[sophiecentaur]

Really? Even the more modern theories are not accurate? Have we found some error in measurements or is it your own personal view?

Why would you expect them to be accurate just because they are the latest? Surely, all you can hope for is that they are possibly 'more accurate' or cover a bigger range of circumstances. Can you really believe there is an 'ultimate answer', somewhere?

At a very basic level, you could never hope to 'measure' pi accurately because all measurement has a limited accuracy so you couldn't hope to produce a trancscendental number by using a ratio of two quantised values. But that wouldn't spoil anyone's day because it's real life.

 

[Avichal]

Why would you expect them to be accurate just because they are the latest? Surely, all you can hope for is that they are possibly 'more accurate' or cover a bigger range of circumstances. Can you really believe there is an 'ultimate answer', somewhere?

At a very basic level, you could never hope to 'measure' pi accurately because all measurement has a limited accuracy so you couldn't hope to produce a trancscendental number by using a ratio of two quantised values. But that wouldn't spoil anyone's day because it's real life.

I don't know about there being an 'ultimate answer' but surely I thought whatever we know currently is very much accurate and correct (as far as we can measure it).
It feels nice to have nature behave according to simple mathematical laws but of course I cannot tell the nature how to behave.

 

[sophiecentaur]

I don't know about there being an 'ultimate answer' but surely I thought whatever we know currently is very much accurate and correct (as far as we can measure it).
It feels nice to have nature behave according to simple mathematical laws but of course I cannot tell the nature how to behave.

It does feel nice when we find it behaves close to simple mathematical laws. But should be expect it to follow them to an infinite degree? The Maths we use assumes continuity in the set of numbers we use but there's no reason to assume that Nature is not granular. We made that mistake before, several times, in history.

 

[Naty1]

Even the more modern theories are not accurate?

That's not quite what I posted. I was implying in my earlier post many not 'perfect' or 'not perfectly accurate' theories. One sense in which they are not 'perfect' is that already expressed by sophiecentaur.

I had something different in mind: An example where GR and QM each 'go awry' [diverge] are at 'singularities'...like the big bang and the centers of black holes. That doesn't mean the theories we have are not VERY useful, but all have domains of application. 'Coulombs law' [of electrostatic charges] is another example of a very useful, but not absolutely precise, 'law': It also diverges at r=o rendering useless results right there and it turns out is only generally valid for stationary or charges. [It IS known how to adjust that for moving charges but I'm not sure about arbitrarily small radii.]

If we had REALLY perfect theories and the underlying math, we would not have recently discovered that the expansion of the universe is accelerating, that dark matter and dark energy constitute some 95% of all the matter-energy in the universe and that ALL dogs are descended from gray wolves with over 99% of their DNA. Now that we have those insights we can proceed to the next steps in the evolution of our theoretical knowledge.