Decision-making and rationality
The discussion on the post below is risking becoming a little too broad in my opinion – so I thought I'd try to focus the issue a little (for the time being).
I've stated on various occasions that the main problem I have with the concept of libertarian free will is its vagueness: Human decisions are, apparently, neither causally determined nor random. Yet quite what they are is never fully addressed. To me it seems that not only is LFW unprovable, it's not even describable either.
To this Alex has replied:
Which seems odd to me since you must assume it with every genuine deliberation you make. One would thing a persistent and ongoing experience of a certain phenomena would count for something.
But is this the case?
Does making a decision require that the decision-maker hold some form of LFW? Let's say that I'm faced with the decision of whether to have a final slice of pizza or not: The crucial factor here (all things being equal) is how hungry I am. If I'm hungry enough I will eat the pizza. If not then I won't. This decision doesn't require any grand supernatural view of human nature – it simply requires a dislike of hunger. What about deciding whether or not to buy 'The West Wing' on DVD: The crucial factors (again, all things being equal) are how much I enjoy the show and how much money I have to spare. These factors are determined by biology and environment – We don't choose whether we're hungry or not. We don't choose what we enjoy or get bored by.
The various factors that go into the decision-making process are usually quite numerous, but they all break down into a simple cost-benefit style of analysis. If the pros of joining my friends at the pub outweigh the cost then I'll join them at the pub. If it doesn't then I won't.
Under the determinist conception of decision-making the result is (putting randomness aside for the moment) entirely dependent on the circumstances. If the level of hunger is above a certain point the pizza will be eaten, if below then not. If the temperature outside is too cold then I won't pop out to the shops, if it's not then I will. This is because the individual is rational – they will act in the way that they see as best satisfying their desires (at that moment in time).
Libertarian free will, on the other hand, seems to conflict with this idea of rationality. Let's say there is an individual (Matt) who, being quite hungry, has just spent twenty minutes making dinner. The meal is done and Matt sits down to eat. However, the universe now splits in two: In the first (deterministic) universe, Matt A eats the meal. In the second (libertarian) universe, Matt B does not. Matt A's actions require little explanation, as they're perfectly rational – he was hungry, the food was ready and therefore he ate. Matt B's actions though seem quite odd. There was no reason for him not to eat the food, he simply chose not to. We cannot talk of his decision in rational terms – It was not the case that he wasn't hungry or that he had something better to do (as the cost-benefit analysis can't explain decisions in the Libertarian universe). So his decision must be irrational (yet at the same time meaningful).
As I can't reconcile this with my own experience of decision-making (I do things for a reason) my experience of deliberation provides no support for a non-deterministic theory.