Saturday, 20 April 2013

Will the real Reality please stand up...

I sometimes find myself in this recurring debate ... it's not terribly serious, it's the old one about waves and particles but in field theory.

I have long held the position that, in QM, what you can detect is what is (physically) real - everything else is just maths. I've thought this position is a form of empiricism.

In fundamental physics, what you detect is, oversimplifying a tad, particles.

But I keep running into people who will tell me
  "but hang on - just because you don't detect something, does not mean it does not exist."
Which is to say, the Universe exists outside our experience of it. That's, what?, realism? Existentialism?

The idea is that the field of Field Theory is more fundamental than what we detect as it gives rise to the particles. We may not be detecting fields - but we do detect their effects.

I'm thinking that, then, the only way to distinguish a "real" fundamental field from one that just happens to produce the right numbers is Occam's Razor ... and we may not even have that because many of the same people will expound on the physical reality of those "virtual particles" that mediate forces in particle physics while I'd call them "math" because they crop up as a step in a calculation process called "perturbation theory".

I could point out that "more fundamental" is not the same as saying "real". It could be a more fundamental maths.

One of my old professors points out that the concept of "reality" may not mean much in Quantum Mechanics ... that's a lot of help!

In QM, "steps in a calculation" have this way of biting you. For instance, there is a "sum over many paths" formulation for reflection famously demonstrated by Feynman which has the anle of reflection and incedence equal only on average (after all the other possible angles have added and subtracted out).

That's just a calculation - one where there are lots of intermediate steps. Does light really follow unequal angle paths? Well, it's easy to check - just remove the bit of the mirror where the angles would be equal and see. Sure enough, you get a reflection! It's dimmer, but it's there. The light that makes the reflection could not follow the rules you learned in secondary school.

You can take this further - but you get the point. So what is "real" here?

Thursday, 11 April 2013

Equal Marriage (thoughts)

The trouble is that the word "marriage" has religious, social, and legal meanings now - and the different meanings get mixed up. When you get married there are three parts to the process to reflect this:
the religious ceremony: even civil weddings usually have some spiritual/symbolic aspect;
the legal ceremony: usually a hurried affair of signing the papers;
the social ceremony: i.e. the reception - speeches and so on.
Leave out any of them and you don't "feel married", as most of you who are married will no doubt attest. If you miss out two, people tend to really notice... and this is an emotional topic so feelings are important. The point is not just to get hold of some assorted legal benefits and obligations but to convince everyone who is important to you that this relationship is serious - you both really mean it this time!

Steps 1 and 2 have the same name ... we have to use the words "in law" or something to distinguish them. Either one would be a marriage - but you are only married in law if you do step 2.

Step 3 has a different name. It is not normally thought of as part of the marriage itself but if you leave it out the feeling is different: it feels like you don't really mean it. So - everybody does something.

The equality folk want step 2 to be the same contract for all couples. Since this step is, in real life, separate from step 1, you'd think there wouldn't be much fuss.

It would be so much easier if they [steps 1 and 2] had different names.

We could strike "marriage" from the law books and replace it by that different name. That would be logical and neatly gets government out of the marriage business.

There are some problems with this.

It doesn't feel the same - people don't want to get "civil unioned" they want to get "married". Probably just need a better name than "civil union" but why can't you just call yourself "married" if you feel like it?

This is what is actually going on: religious people want to reserve the word "marriage" so that not just anybody can claim to be married. Just like not just anyone can call themselves a lawyer or a doctor. But, instead of being about a professional standing, it is more about branding. People claiming to be married in religion are claiming a status for their relationship in the context of that religion. So it is more like not everyone can claim their touchscreen tablet computer device is an "iPad".

It is about the (market) position of that religion in society, their social identity is under threat, they want to protect it.