My first reading in Introduction to Philosophy comes from Galen Strawson’s article for The Stone, Your Move: The Maze of Free Will.
Determinism is the theory that everything that occurs in the world has a cause, all the way back to the beginning of the universe. As an illustration, the reason that you’re reading this now is that somehow you chanced upon a link to my blog/already know about my blog/happen to be beside a friend reading my blog, etc., which in turn happened because you were either randomly surfing the net/feeling bored and decided to see if my blog is still alive, etc, which in turn happened because … of a whole causal chain of events that can be traced back to your birth, your ancestors’ births, your ancestors’ ancestors’ births… so on and so forth. The corollary to this theory is that if we know all the causal laws governing the world, we can predict exactly all future events in the universe. This was the idea conceived by the French mathematician Pierre-Simon Laplace, the idea which we now know as Laplace’s demon.
At first glance, determinism sounds a little outlandish. But no – in fact the opposite would be completely inconceivable. Suppose your door creaks open all of a sudden. What would you think made it happen? It could be a gust of wind. No, maybe someone is trying to play a prank on you. No, there’s no one at home. Maybe it’s gravity – the door isn’t hung level. Wait, the door is dead level. So why exactly did the door creak?
Notice something: you need a reason for why the door creaked open. Whatever it may be, a ghost, the wind, a prank, gravity… whatever it is, you feel the need to attribute this to some cause. Would you accept that the creaking of the door “just happened”? This was the 18th century philosopher David Hume’s argument: that whether or not we admit to believing in the idea of determinism, we do in fact believe in it, that there is a sufficient cause for everything.*
So why do we care whether determinism is true or not? For us to have free will, we must be in ultimate control of what we do. We do what we do because of who we are, which is a product of prior causes over which we have no control, such as upbringing, genetics, etc. If we do not have control over such factors, we cannot claim to have ultimate control over what we do. Therefore: we do not have free will.
You may or may not buy this argument, but the implications are huge. If you do, the next time somebody upsets you (say by talking very loudly in the library or barging into the MRT before you can get out, causing you to miss your stop), you have to remind yourself that he did not choose to do so freely; rather, his actions were caused by factors beyond his control, and had you been in his situation, with the exact same upbringing, genetics, etc., you would have done exactly the same.
Alternatively, even if you do (I do), you can choose to be illogical and hold that person morally responsible (I do too).
*Example taken from Bruce N. Waller’s Consider Philosophy.