The "standard model" explained

Nice piece in today's The Conversation that starts;

The “traditional” beauty of theoretical physics is its equations. If we want to describe something, or the way something behaves, we can write down a relation between some properties we think that thing will obey.

The simplicity and symmetry of these equations – to someone who understands them – is amazingly beautiful.

So far so good. Yes that is a joy of Physics.

But the piece goes on to say;

Given the mass of a ball, the height, angle, and strength with which it is thrown, physics will tell you the path the ball with take through the air, how long it will be in the air for, and how far away and how hard it will hit the ground.

Physics can fully describe this system with just a few simple properties.

But, of course, it can't. Projectile motion happens in the real world so on top of the simple model based on initial velocity and gravity you need to allow for air resistance. The next simple iteration is to assume air resistance is proportional to velocity and tweak the model.

But real atmosphere has "winds" - and they are incredibly complex systems that can only be modelled statistically.

The system cannot be "fully described". It can be "satisfactorily described" for most practical purposes - including artillery attacks, dropping bombs and shooting rockets into space.

All these little perturbations matter when you get down to the level of particle physics.

The "standard model" of particle physics is both well described but also fails to account for all empirical results and has too many variables to really be a meaningful "explanation".

The search goes on for something better. I can't help wondering whether the physicists are all looking in the wrong places because they still believe this stuff about their ability to "fully describe" any system.

Note: An unfortunate side effect of this is that economists believe economic science can "fully describe" the economic system.




Novae Meridianae Demetae Dexter delenda est

The New Paternalism

The Economist has an item on what they call "The New Paternalism". It is a commentary on a number of approaches that put a more friendly face to government interference. The paper (as it calls itself) is, of course, still dismissive - being as they are bastions of a a highly principled liberal tradition.

However some of the suggestions are worthy of greater consideration. The ability for a citizen to volunarily restrain themselves from undertaking certain acts in such a way that cannot be broken is a very good idea for people who have a problem addiction (though possibly not as good as some forms of therapy) and especially for people who might have a psychological problem (how to limit a bipolar personality from accessing their credit card). But it does seem open to abuse if it is a substitute where an individual could be reasonably expected to exercise control.

Of far more interest is the recognition that the way choices are presented to individuals will change outcomes. The example given being that if the individual has to opt out of a pension scheme rather than opt in, then participation rates increase. This is one case where the lessons of behavioural economics interestingly intersect with the concepts of institutional economics - the latter being the proposition that the institutions within which markets (the making of choices) operate matter.

The discussion opens up a whole world of realisations that we should be debating a lot more how Governments act than if they should act. In one area close to my heart, business regulation, it is an area way too infrequently considered - so we get lots of advocates aligned for more or less regulation but blessed few discussing how any regulation should be done.