THE WORLD ACCORDING TO PHYSICS.

1.

A common-sense thought is that nothing moves unless there is a force acting on it. This is demonstrated by examples such as when I push a heavy stone along the ground and it is moving because I am pushing it and it would not be moving if I wasn’t pushing it. But then we get instances which seem to show that the common-sense thought is not true.

Three examples. First, if I push the stone hard enough, it will carry on moving for a bit even after I have stopped pushing. Second, when I throw something into the air it will keep moving despite the fact that, after it is released from my hand, I am no longer exerting any force on it. Third, falling objects are moving downwards but there seems to be nothing that is pushing or pulling them that way.

The common-sense thought can be maintained in the third example if we explain the motion in terms of a non-contact force, namely gravity.

But in the case of the second example about thrown objects it turns out that the common-sense thought is actually wrong. Thrown objects are moving the way they do even though there is no force acting on them to explain this motion, contact force or otherwise.

2.

Another related issue is: what’s the force that keeps the particles that things are made of stuck together. For example, why don’t the particles that compose the under side of a table fall off because of gravity? I suppose the answer is: intermolecular force. That’s the force that is keeping any particular particle together with the one above it. But this is only a partial explanation. I also need to know the circumstances under which this force happens.

So the force of gravity happens because of the things concerned having mass. And electro-magnetic force happens due to things having electrical charge. So then we can ask about the intermolecular force that keeps matter together: what does it happen because of? Is it just proximity? But if I take a piece of wood of the kind that some table is made of. And I press this hard onto the underside of that table. That doesn’t stick there the way the already present bits of wood are stuck there. The proximity due to the pressing hard does not cause the intermolecular force to happen.

In sticky substances like honey and glue are the intermolecular forces stronger? Is that what makes them more sticky?

3.

In Physics it might be that everything is just forces and there is no matter at all. (Didn’t Faraday say something like this?) So we could say that any lump of ‘matter’ is just a phenomena where a repulsive force acts on anything that gets to the spatial boundary of some region in space. To which region we then give the name ‘matter’. We could therefore account for solidity via statements about forces. We wouldn’t need the concept of matter at all.

I get the impression that Physics doesn’t tell you what reality is at all. So Physics says that atoms are like tiny spherical orbital systems with electrons orbiting or huddling around a nucleus. But Physics is only saying that that’s what an atom is ‘like’, as in what they are similar to. It’s not saying that that’s what an atom ‘is’. Atoms are like spheres, that doesn’t mean they are spheres. (This is all rather like the way Jesus would say “the Kingdom of Heaven is like” and then some description of seeds or whatever. He never says what the Kingdom of Heaven actually is.) But I think I am just confused here. Because the phrase “this is what it’s like” often does mean “this is what it really is”. The word ‘like’ doesn’t mean ‘similar to’.

Physics can’t answer questions like: What is the relation between some element’s properties and its subatomic structure? Why is it that carbon is a solid but something whose atomic structure differs by only one proton (and neutron and electron), namely the gas nitrogen, is something completely different? How does the atomic structure of nitrogen make it the sort of thing that it is?

[5 March 2017]

[Last edited 2022]