I think that's a poor analogy. The earth is what it is no matter how you define it. I could define my brother as a green triangular alien from the moon, but that would be objectively, factually wrong. (I put define in scare quotes because such delusions as a flat earth or my brother as an alien are not so much wrong definitions of concepts as wrong descriptions of physical objects.)
The difference between your green brother and the earth as the flat surface in the centre of the earth is that people believed in it for ages. But of course, such comparisons might not work to the end.
Free Will on the other hand is an abstract concept (rather than a physical object) that gets it definition from, well, how the people define it kind of like the word square.
Yeah, right, that's true. But if we discover that a concept used by the majority of the people cannot stand a critical logical analysis, then it is just wrong. Libertarian free will is such a concept: it has no coherent meaning at all. Define free actions as movements that are not caused by previous events: then they are random. If 'we' are doing it, i.e. 'we' can change the course of nature with our will, then we are causes. But that means actions
are caused. By what? The soul? Besides that science has done away with the idea of a soul, what would motivate a soul to its intentions, uncaused? No, libertarian free will is a conceptually empty concept.
If the vast majority of people including philosophers and theologians, historically define something a certain way, and then a subset (compatibilists) of a very tiny subset (philosophers) of society comes along and says no, the unwashed masses don't know what they mean when they use a word that has always meant what they foolishly think it means because we have a better idea of what this word should mean that is rather different that what it has always meant to nearly everyone, then in my opinion those philosophers are engaging in pure redefinitional* sophistry born out of desperation to save a concept they hold dear.
No. Compatbilist Free Will (CFW) contains everything we normally connect to the idea of free will,
except that it is uncaused.
1. CFW describes free will as being able to do what you want (or a little bit more technical that wishes and beliefs are causes of actions). I think everybody will subscribe to this.
2. CFW shows how the modal meaning of 'could have done otherwise' fully covers the meaning we attach to it also in the context of free will. It is a conceptual misunderstanding of 'could have done otherwise' to take it as 'could have done otherwise' in
exactly the same circumstances, including the brain being in exactly the same state.
3. Higher animals, especially human animals, are able to anticipate the consequences of their actions. They can picture themselves and their environment in the future, dependent on which action they will take. There is no reason to think that such an evaluating entity cannot be implemented in a determined system, like the brain. A chess computer is also a 'possibility evaluating system', for every move it has different possibilities. But it is a determined system.
4. Societies can, by connecting consequences to actions (praising, rewarding, blaming, punishing, etc), take influence on people, and so form a basis for ethics and our judicial system. People can discuss this rationally by evaluating arguments, because they are 'evaluting machines'.
5. Having free will does not mean being uncaused, but that I am not following the wishes and beliefs that are my own, i.e. that I am coerced to my action, that I am intentionally falsely informed etc. Therefore such actions can be excluding grounds for guilt in court cases.
The illusion of
libertarian free will can arise because we have no access to our hardware layer, the neurons. We do not observe how we are determined. Thoughts and feelings seem to pop up from nowhere, and in the meantime we still feel that our feelings, thoughts and actions are ours, that we are the
independent author of these. That gives the feeling of not being caused. The illusion of libertarian free will is the companion of feeling as an entity seperate from our environment, even from our bodies. Give up this idea, and CFW logically pops up as the only meaningful sense of what free will is.
I don't know what you mean. What does defending morality and ethics have to do with being a compatibilist?
If you are a hard determininist, then you deny the existence of free will alltogether. Then you have no basis anymore to praise or blame people for their actions: one should not
punish criminals, but
treat them as disfunctional objects. Because Harris doesn't do this, and still makes a distinction between actions that are morally culpable and those that aren't, he shows that he is a closet compatibilist.