Introduction
Approximately 1 year ago, I posted a 'proof' for the absence of free will.
The post drew a wide range of interesting and answers and comments. The most persuasive challenges related to the nature of decision-making; in particular to:
a): Can an act ever be voluntary in the absence of decision to perform it?, and
b): How might a decision be defined if it is to be defined as something other than an act?
Most important to the original 'proof' was the realisation that the claim a 'decision is an act' - whilst accepted by some - is philosophically controversial.
As Strawson (2003, p. 244) points out:
"What about choices and decisions? These are clearly mental actions?"
Some are, but the case is far from clear... Very often there is no action at all: none of the activation of relevant considerations...It simply happens, driven by the need to make a decision...There is no direct action in the actual issuing of new content, any more than there is in the growth of trees one has planted.
With this in mind, I have added three premises which attempt to accomodate this challenge, although these additions do contain another assumption which is addressed below the argument.
Justification
I have posted this formulation as an answer to the original post, but there is clear value in posting it here as a new question, for the roughly 800 people who viewed the original post are likely interested in its development and will most likely not be made aware of this revision unless it is posted here as a distinct, new argument; one open to fresh critique. Of course, some objections that were deemed pertinent to the first argument may again be deemed pertinent to this version. In these cases, reposting an answer verbatim is certainly useful, but a comment with a link may be sufficient. Any expansion on an original answer would benefit from a new post here.
Argument
As in the previous iteration, an 'act' here is defined as 'a thing done', as per Oxford Languages definition #2.
1. Decisions may be either voluntary or involuntary.
2. Insofar as free will requires the ability to make voluntary decisions, those decisions which are involuntary cannot contribute to free will.
3. Any voluntary decision would constitute an 'act'.
4. However, in order for an act to be voluntary, a person must decide to perform it.
5. Therefore, in order for a decision to be voluntary, a person must decide to decide it (perform it).
6. This leads to an infinite regress of prior decisions, in which any voluntary decision requires an infinite chain of prior decisions.
7. Insofar as free will requires the ability to make voluntary decisions, free will is impossible.
Whilst I am interested in all answers/comments, experience from the previous posting suggests that the most productive answers clearly identify and attack specific premises or at least clarify how any point being made is directly relevant to a specific premise/premises.
Clearly, this argument depends on a new assumption, namely that a voluntary decision is always an act. If you believe there is any way for a voluntary decision to be a non-act, this would prove crucial to countering this revision.
Reference
Strawson, G. (2003). Mental Ballistics: the Involuntariness of Spontaneity. Proceedings of the Aristotelian Society, pp. 227-256. DOI: 10.1111/j.0066-7372.2003.00071.x