Saturday, 17 November 2012

Probability and Free Will


If you flip a coin, what are the chances that it will come up heads?




Most people would say 50/50, 50% or approximately half of the time, in the long run.

What about if you dropped a coin on its thin round side, so that as it hit the surface it would fall or bounce and land on one of its flat surfaces?  Most people would say, once again, that the odds of it coming up heads would be about the same; 50/50.

But what if the coin was perfectly flush on both sides, its mass was perfectly centred, and it was dropped perfectly straight down in a vacuum, and landed on a perfectly flat surface?  Would there still be a 50% chance of it coming up on any one particular side when there are no physical variables to make it favour one side over the other?  In such an environment, would the lack of lateral imperfections have it land on its round edge?

The Spear is going to go out on a limb and say that, in the macro world at least, probability is an illusion; nothing more than an expression of human uncertainty of what are otherwise fixed outcomes in a determinate world.  No outcome is any more ‘likely’ than any other; shit just happens according to the rules.  It is only our imperfect knowledge of the contributing variables which creates the illusion of uncertainty as to the particular shit which is going to happen.

‘But what about the freedom of choice?’ The Spear hears you say.  ‘I am not a coin in a vacuum.  I have free will.’  You’re right, you’re not a coin; you’re a biological machine whose uncertainty as to its own function creates the impression of choice and free will. 

You get offered to pick a card from a regular deck.  What are the chances of you choosing any particular card?  ‘1 in 52’ you say?  That would be to assume that as your hand selects a card, it is doing so for NO REASON AT ALL (like the coin in the vacuum falling to any one side).  It would be to say that your brain, with zero input, has randomly produced some electrical signals, and by luck, those signals were to carefully pick out an entirely random card from the offered deck. 

But of course in reality there was some input (being shown the layout of the deck, hearing the instructions to select a card, the expression on the face of the person giving the instructions, etc.), your brain processed this input and then from it formulated an output, which was to select that specific card.  There was never any chance involved, only an uncertainty as to the processes bringing about the eventual selection.

When we say that the chances of a coin flip are 50/50, or the selection of a card is 1 in 52, what we are really saying is that our ignorance of the factors at play is basically equal regarding all of the outcomes.  If we were to know that there was a weight on one side of the coin, or a stacked deck, then we would say the odds would be different.  However in reality the coin is always weighted and the deck is always stacked, just in a way that is very hard for us to detect.

When we know more about the values of the variables at play, the ‘probability’ of some outcomes increase, while that of other outcomes decrease, and the outcome becomes more certain.  What may have at first been 50/50, may with more knowledge become 90/10.  Knowledge lets us strip back the illusion of probability somewhat, and in cases of inviolable data, virtually destroy it.

In the macro world, there is only one probability of each actual event; 1.  Things either happen or they do not, and those things which were never programmed into the universe are not even possibilities, they are non-outcomes with a likelihood of 0. 

As imperfect creatures with imperfect information, we will always find ourselves subject to some degree of uncertainty.  And perhaps that is a necessary requirement if we are to remain content with our apparent free will.  So long as it feels like we live in a world of opportunity and possibilities, there is always reason for us to hope for a better lot.  And why not; for all we know that might just be what the universe has in store.

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