Catholic and Loving it!

If anybody walked in late, this is part three of my ongoing series on why I bother going to Church at all when it's full of women and I find the music and architecture so dreadful and several things the Church says shouldn't happen when you go to Church happen with alarming regularity.

The last couple of blog entries on this subject (part one and part two) took a bit longer than strictly necessary to say the following:

Some things are better than others.
The more you know about things, the better you can make things.
There are some things you have to find out for yourself.
The Scientific Method is a good way of finding things out.

So far, I've basically explained why I bother with Science. This is a fairly brief summary of my philosophical views from childhood to my teenage years. I practiced what I preached as well, choosing A-Levels (exams you take at 18) in Mathematics, Chemistry and Physics. You have to really like science to do that kind of thing.

But science has it's limits.

Constants and Variables

In a scientific experiment, a constant is something you keep the same (is is constant). A variable is something you change (it varies). One of the limits in a scientific experiment is that you can only change one variable at a time.

For example, in my last blog entry I mentioned an experiment with a bouncy ball. I dropped the ball from a different height to see how high the ball bounced. Because the only variable I changed was the height, It was possible for me to say that the change in bounce height was due to the change in drop height. What if I had dropped the first ball from one metre and then dropped a heavier ball from two metres. Could I say that the change in bounce was due to a change in height? No. I now have two variables, the change in height and the change in weight. It is impossible for me to know how the height or weight affected the bounce.

If I want to know how the drop height affects the bounce height then I must keep the weight constant. If I want to know how the ball weight affects the bounce height then I must keep the drop height constant. If I want to definitely know that the reason my ball bounces higher is because I dropped it from higher then I need to definitely know that the height is the only thing I changed. Everything else must be exactly the same. Everything else must be constant.

Making Assumptions

The practical problem when you come to do an exeriment is that you cannot keep everything the same. You can use the same ball both times (to avoid the weight changing), you can make sure to do the experiment indoors (to avoid wind conditions) but you can't do everything.

For instance, as we conduct our experiment we know the moon is circling the earth overhead causing the eb and fow of the tides. The ever changing gravitational force of the moon that pulls huge quantities of salt water up and down the beach twice a day surely has some small effect on our ball. Our bouncy ball is made of rubber, which degrades over time. When we bounce the ball the second time, it will have just bounced the first time. Does bouncing a ball change the ball? We can avoid the effects of time by dropping two balls at the same time but then we can't use the same ball. We can't drop the same ball in the same place at the same time.

So what to do? Make assumptions of course!

We know the moon is having an effect, but we can assume that the effect of the moon is negligible. Negligible means "too small to make any difference". Our rubber ball degrades over time, but we don't plan to leave it in the attic for twenty years between drops. We assume the effects of rubber degradation will be negligible. Our bouncy balls will probably not bounce on the exact same spot on the floor but we do our best and assume the floor is exactly the same all over the room. You get the idea...

The important point is this. We don't just hope these assumptions are true, we need these assumptions to be true. They are required. If the moon does significantly affect our ball, then we can't ignore it. If the floor is covered in spikes, we can't assume that it makes no difference where the ball lands.

Science requires certain assumptions to be true.

Making Ridiculous Assumptions

I call the following three assumptions ridiculous because if I had written them on a lab report during my physics degree I would probably have been subjected to ridicule. Yet these fundamental assumptions are at the root of every scientific experiment. Science doesn't just assume these things, science requires them to be true. If they were not true, then science wouldn't work.

- Things don't just happen for no reason.

Everything has a cause. When we let go of our ball it doesn't just fall for no reason, it falls because of the force of gravity acting upon it. If our bouncy ball suddenly shoots off to one side we assume something must have collided with it mid air, perhaps we stood on a chair to drop our ball and the ball struck the chair. Whatever. We assume that bouncy balls don't just shoot off for no reason.

Remember. To be able to say that the change in height is what caused our ball to bounce to a different height we need to keep everything constant. Then we can say the height caused the change. If things happened for no reason then we could never say that. We would always have to wonder "maybe it bounced higher for no reason". That would not just be stupid, it would make science impossible.

- Things have no choice.

We must also assume that nothing has any free will. In every experiment we assume that the protons, neutrons, electrons that make up our bouncy ball always follow the laws of physics. They have no choice. Our bouncy ball doesn't fall half way and then decide whether it feels like bouncing, it just bounces. That's how the physical world works. We might occasionally say things like "my computer seems to have a mind of it's own" but we know that it does not. It is just protons, neutrons and electrons bouncing around according to the rules.

If our bouncy ball had a choice, we would need to keep that choice constant. We would need to make sure the ball chose both times to bounce as hard as it can. The electrons in my PC would organise a union and ask for better working conditions. Science would be impossible.

- Things are not right or wrong, they just are.

There is no morality in physics. It is not wrong to drop a ball from a height of one metre. It is not any righter or wronger to drop a ball from a height of two metres. We do not have to worry about how evil our act is. Plunging a knife in to a mans chest might be wrong if you are a murderer and right if you are a surgeon but the physics of plunging a knife in to a mans chest remain unchanged. If it's the same knife at the same angle in the same chest... this is getting a bit disturbing.

This is lucky for science, because we can't measure right and wrong with a ruler. We can't see it under a microscope. We have to assume that it makes no difference. Otherwise the scientists trying to cure cancer might get different results from the ones trying to develop bombs. Science would be impossible.

Let's recap that..

Science requires certain assumptions to be true.
- Things don't just happen for no reason.
- Things have no choice.
- Things are not right or wrong, they just are.

As long as those things are true. Science should be okay.

(I wonder if anybody is reading these things...)