You have a certain aversion to bearing any burden. That fact doesn't bode well for you. — creativesoul

But the definition of a second, that's not a part of nature. That's something humans did. — fishfry

Is this relativity itself relative? Or understood as an absolute? — t0m

And was it not established on an assumption of the uniformity of nature? — t0m

Well, not really - there's still the outstanding problem of dark matter. — Wayfarer

Just by way of footnote to the above, abstracts of the other two 'greatest problems' — Wayfarer

it's easy to imagine a 'smug quietism' misreading genuine logical tensions as language on holiday, complacently waiting for the acknowledgement of such tensions to become conventional, respectable. — t0m

Very surprisingly, CP is not significantly violated by the strong nuclear force, and no one knows why. We know the strong nuclear force does not violate CP symmetry very much because of a certain property of the neutron, called an “electric dipole moment”.

Now, how big would you expect the dipole moment of a neutron to be? Well, the neutron has a radius of about 10-13 cm, so you’d expect D should be about that size. And it consists of quarks, anti-quarks and gluons; the gluons are electrically neutral, but the quarks and anti-quarks have electric charges: 2/3 e (up quarks), -1/3 e (down quarks), -2/3 e (up anti-quarks) and +1/3 e (down anti-quarks). So you might expect q to be about that size. So you’d expect the neutron to have an electric dipole moment with a size in the vicinity of 10-13 e cm. That’s about a million times smaller than the dipole moment of a water molecule, mainly since the radius of a neutron is a million times smaller.

Actually there are some subtle effects which make a more accurate estimate a little smaller. The real expectation is about 10-15 e cm.

But if the neutron had an electric dipole moment, this would violate T, and therefore CP, if CPT is even an approximate symmetry. (It also violates P.) So if CP and CPT were exact symmetries, then the electric dipole of the neutron would have to be exactly zero.

Of course we already know that CP is not an exact symmetry; it’s violated by the weak nuclear force. But the weak force is so weak (at least as far as it affects neutrons, anyway) that it can only give the neutron an electric dipole moment of about 10-32 e cm. That’s far smaller than anyone can measure! So it might as well, for current purposes, be zero.

But if the strong nuclear force, which holds the neutron together, violates CP, then we’d expect to see an electric dipole moment of 10-15 e cm or so. Yet experiment shows that the neutron’s electric dipole moment is less than 3 × 10-26 e cm!! That’s over ten thousand million times smaller than expected. And so the strong nuclear force does not violate CP as much as naively anticipated.

Why is it so much smaller than expected? No one knows, though there have been various speculations. This puzzle is called the strong CP problem, and it is one of the three greatest problems plaguing the general realm of particle physics, the others being the hierarchy problem and the cosmological constant problem.

I don't expect to be suddenly wiped out by a change in the 'laws' of nature, but I have yet to see a way around Hume's 'problem.' — t0m

How would we know 'officially' if the transitions were slowing down or speeding up? — t0m

How many trees are there, one or ten? — Banno

Or alternatively 'no reason to assume the universe is anything but a contingent accident'. — fdrake

So much for 'symmetry breaking' :-} — Wayfarer

if you want to argue that preliterate hunter gatherers aren’t skilled at transmitting cultural metacognitive thinking via their oral skills, then you show me any such evidence. — apokrisis

That's not quite how I would say it, but not far from what I would say — Banno

All this just to show that there is a deal of ambiguity in the question — Banno

As I understand it, the philosophical understanding of 'substance' has never been allied to its common understanding as "stuff", so it's not at all clear what you are actually referring to here with your " But it’s all a colossal mistake, a category error, a misreading". — Janus

the multiplicity of trees is implicit in the question raised by the OP. — Banno

But is the tree mental when we actually perceive one (see, smell, touch, hear it fall in the woods, etc)? — Marchesk

Seems overly complicated. — Banno

Unless humans have always been linguistic creatures, it seems to me that there is a progression of complexity at work. — creativesoul

On this forum, no one, but there's not many right-wingers here. I'm tempted to say apokrisis, but not sure if it's best to identify him as right-wing. He sounds like neither. — Agustino

It just means that our physiological sensory perception has limitations and as such doesn't perceive everything. — creativesoul

Not all perception requires language. — creativesoul