The Illusion of Free Will
Free will is an illusion. I will try to explain why I believe this is the case using a scientific and a philosophical argument. I want to first clarify what I mean by "Free Will." I think that free will can be defined quite simply as the ability to have acted differently. In other words, if you could go back in time at any point in your life you have the ability to have made a different choice. This is demonstrably false.
Scientific Case against Free WillOne of the strongest cases against free will have been studies done by neuroscience to study our decision making process. A study done in 2008 showed that researchers could tell what decision a participant would take up to 10 seconds before they became aware of their decision. This and other studies have put into question the idea that we are the authors of our own actions. It seems to me at this point one fact is indisputable, some moments before we are aware of what we'll do next, our brains have already determined what we will do. It is only later that we become aware of the process of having made a "decisions." Sam Harris says it best in his book Free Will:
Consider what it would take to actually have free will. You would need to be aware of all the factors that determine your thoughts and actions, and you would need to have a complete control over those factors. But there is a paradox here that vitiates the very notion of freedom - for what would influence the influences? More influences? None of these adventitious mental states are the real you. You are not controlling the storm, and you are not lost in it. You are the storm.
Philosophical Case against Free Will
Following Harris's logic indeed in order to have free will we would necessary need to be aware of and have control of everything that determines our choices: environmental factors, our current moods, other people, past experiences and much more. This is simply not possible. Think about a movie. Why did you choose that movie? Why did you not choose The Avengers or Harry Potter. Did you have any control on why you chose that movie? Could you have chosen to want to to choose another movie? Of course not, not any more than you can choose to like one song over another or choose to like chocolate over vanilla ice cream.
Everything that you think and do arises from prior causes in which you have no control over. You did not choose your parents, your genes, where you were born and your upbringing. Most of these come down to luck. Where is the free will in that?
Your choices still matter
Free will is an illusion but it is indeed a very useful one. Dispelling with the notion of free will need not make you fatalistic. Actions will still have consequences, and what you "choose" to do will still matter to your personal life. You just don't have control over what you "want" to do. And do you ever really do anything on purpose that you don't want to do? Excluding being forced to of course. If what you've read has convinced you that free will is an illusion, you had no choice in the matter. If you remain unconvinced, again you had no choice in the matter. Freedom never entered into it.
Knowledge still matters. David Deutsch says that everything, not forbidden by the laws of physics, is possible as long as you have the right knowledge. With or without free will beliefs will always have consequences and knowledge helps us make better choices.
Sources:Harris S, 2012. Free Will: https://samharris.org/books/free-will/
Surviving The Cosmos - Waking Up with Sam Harris and David Deutsch
Bode S, He AH, Soon CS, Trampel R, Turner R, Haynes J-D. Tracking the Unconscious Generation of Free Decisions Using UItra-High Field fMRI.