Wednesday, 30 October 2013

Why Time Exists

It's quite common to come across science articles which argue that there isn't really any such thing as time.  This is a strange thing to say, if only because time is central Einstein's theories of Relativity.   It may be that time need not be present in Quantum Mechanics, but there is no evidence that QM is the central theory of physics.

However, there is a more everyday reason to believe that time exists, and that is that we have a word for an experience that we call time!  There is a thing that we use to label certain experiences of reality.  When a clock ticks, we refer to the duration between the ticks as the passage of time.  That duration is the cause of our use of the word 'time'.  

Time probably doesn't operate the way we think it does.  For example, it's not easy to understand what 'the flow of time' actually means.  But that doesn't mean that time itself doesn't exist.  Don't let the physicists try and persuade you otherwise!

Friday, 18 October 2013

Why the Many Worlds Interpretation of Quantum Mechanics isn't Deterministic

It's often said that the Many Worlds view of quantum mechanics simplifies things because it's purely deterministic - as all outcomes of quantum possibility do actually occur.  This is a mistake.  There are many problems with this view of the world, and one of them is that it doesn't in any way help with deterministic predictions.  

Consider the good old Schrodinger's Cat situation.  A cat is enclosed in a box with some poison gas and a radioactive source, which, if it emits a particle, will result in the release of the poison gas.  We wait long enough that the radioactive source has a 50% chance of emitting a particle.  Is the cat alive or dead?  The Many Worlds view says that the cat is both alive and dead, but in different realities.  This is in contradiction to the conventional 'Copenhagen Interpretation' which states that, at some point, the possibilities collapse so that the cat becomes either dead or alive in one reality.

Now suppose there is an observer O who tries to guess if the cat is dead (D) or alive (A).  In the Many Worlds interpretation the Observer O splits into two observers O1 and O2, each of which observes one of the possibilities D or A.

So, suppose the observer guesses that the cat is alive.  The possible results of the experiments are:

1. O1+D and O2+A => observer 1 sees dead cat and observer 2 sees alive cat
2. O1+A and O2+D => observer 1 sees alive cat and observer 2 sees dead cat

Which ever of these outcomes is what happens, there will always be one copy of the observer who has guessed wrong, and one who has guessed right.

Like all mainstream quantum mechanical interpretations, the Many Worlds interpretation leaves observers with points in their history which were unpredictably random.  No observer either has a fully deterministic past or a fully predictable future.

Tuesday, 15 October 2013

Our Comprehensible World

"The eternal mystery of the world is its comprehensibility" said Einstein.  No, there is no mystery; it's not hard to understand at all.  If the world was not comprehensible we would not be able to live in it.  Life needs a stable environment to arise and evolve.  Life could not appear in a world of chaos, a world with arbitrary laws where information could not collect and meaning could appear - the digitally stored recipes for building organisms.  We live in a boring region of the universe that is close to being as cold as possible - just a few hundred degrees above absolute zero, and that is nearly empty - nothing like the nuclear densities of neutron stars.  Cold and nearly empty, our world is a place where regularity can exist, where conservation laws apply because one place is pretty much like another and today is pretty much like yesterday.  Our world is full of necessary symmetries, consistencies that make life possible.  Of course our world is comprehensible - worlds which aren't are dead.

Sunday, 13 October 2013

String Theory and Narnia

I just can't read books which involve String Theory. My Spidey Science Sense starts tingling too quickly, and I can't get past the initial assumptions. OK, so modelling reality as tiny strings of energy seems to include gravity, and the model requires at least 6 other dimensions of space, and those dimensions must be small because we can't see them. I can get that far. But when the models start to deal with how strings can curl around those 6 dimensions and so on, I feel the urge to chuck the book out the window (which is a bad idea, as it's usually on a Kindle). You can't use an unverified requirement of a mathematical model (the extra dimensions) as justification for further claims about reality unless or until you have verified that requirement. The existence of the other dimensions isn't a requirement of physics, it's a requirement of mathematics. Someone has got their ontology utterly screwed up. 

String theory is like Narnia. Before you start to present ideas about the landscape of Narnia, you first have to show that wardrobes are trans-dimensional and that the specific land of Narnia lies within.

Monday, 7 October 2013

I'm an atheist but...

I'm an atheist because that's the term for someone who does not believe in gods.  It's important to let others know you are atheist because so many aren't able to do that, and because so many suffer prejudice and oppression because of their lack of belief.

But... I'm not an 'atheist+'.  It's absurd to try and associate positive beliefs about politics with the absence of belief that is atheism.  Even misogynists or racists can be atheism, and their ignorance and hatred doesn't  make them any less atheist.  Atheism doesn't have any innate political views unlike humanism.

But.. I'm not part of any atheist community.  If someone says 'we atheists', they aren't talking for me.  There can be atheist communities, people bonded together because of the consequences of their lack of belief in societies and cultures where belief is widespread and expected.  But I'm not part of any such community.  Anyone who talks of 'the atheist community' doesn't have a clue what they are talking about, as the experiences and different situations of millions can be summed up with 'community'.

I'm an atheist because I don't believe in gods.  If you want to know what I think on any issue you are going to actually have to ask me.

Friday, 4 October 2013

Why there is no soul part 3 - conclusion

I have explained how all stories about what happens in the brain and mind at different levels can be true - reductionism doesn't make the higher-level stories involving thoughts and feelings any less true.  I have shown why what goes on in the high-level stories has to be also present in the 'reductionist' levels as well, because all the stories have to proceed in lock-step: a memory is recalled, many neurons fire and change, and trillions and trillions of particles shift and change, all at once, all locked together into the story.

What this means is that thoughts about the mind are about many levels of mind and brain at once.  When there is a thought about the richness of a colour, this happens in the mind, in the neurons and in the particles.  So, the story of your thoughts is completely present In the level of physics, and all the reality is also completely present in the level of physics.  The story is both about thoughts and about physics at the same time, and if both stories are to be true, if the thoughts about mind are to be correct, then the physical story has to be right about itself.    A physical story that says that there is more than physics involved in the mind contradicts what we know about the low-level physics of the particles that make up the brain.

Therefore, the belief that the mind contains more than physics, that there is a soul, cannot be true.

Thursday, 3 October 2013

Evolution isn't always convergent!

Evolution just does it's own thing.  What may seem like predictability really isn't.  There have been suggestions, as you might expect, that evolution has targets, that it's designed to get to certain types of beings.

There was a great rebuttal to this several years ago by the biologist P.Z. Myers.  It goes kind of like this:

Look at the amazing way that evolution has shaped animals that swim fast through water.  Sharks are like super-streamlined missiles, as are barracuda.  Now look at the dolphin - apart from the angle of fins in the tail, it's the same super-fish-shape as the shark.  The fish shape is a great example of convergent evolution, of how evolution will reach the same designs for the same situation.  Hold on a minute, there's something moving very fast through the water over there - it's a squid.  Oops!

Convergent evolution can happen, but it's not inevitable.  There are sharks, dolphins... and squid!