The Problem of Free Will is the problem of reconciling our ability to choose our actions with the apparent determinism of a world of cause and effect.
I propose that the solution to this problem is that consciousness allows a new kind of cause to create new kinds of effects, overcoming the constraints of determinism.
The universe is said to be deterministic because if we know the location and momentum of every atom in the universe, we also know their past and future values for any given time, because these can be calculated from the laws of classical mechanics. So it’s already determined what is going to happen, and we can’t really be choosing freely when we think we are.
Consciousness depends on the location and momentum of the atoms in the brain. In the nervous systems of the simplest conscious animals, whichever those are, and in the nervous system of a fetus when it first develops consciousness, the location and momentum of the atoms is still determined by classical mechanics.
However something novel is being done with the atoms in all living things. There’s a new kind of force at work, as biology causes the atoms to form repeating patterns and go through repeating processes, the processes which cause the organism to survive as a discrete organism, to reproduce, digest, excrete, maintain its metabolism, all the activities we use to identify life. This force that causes organisms to develop, grow, survive, reproduce, is what I mean by “will”. I am going to say all living organisms have a form of will, but in simple animals it is a mechanical, senseless, blind will.
But highly developed conscious organisms like us can direct the location and momentum of the atoms in our brains. That’s what we do when we think and reason, and when we make active use of our memories. A conscious experience is correlated with a succession of brain states, with the atoms located and moving in particular ways, and when we for example actively retrieve a particular memory, or reason our way through some ideas, then we are causing those atoms to behave in a different way to that which would be determined solely by classical mechanics.
That is how consciousness overcomes the constraints of determinism and gives us free will.