I am attempting to construct an argument against free will.
An early objection has been raised, to the very first premise:
1. Decisions may be either voluntary or involuntary.
In Human Nature: the Categorical Framework, Hacker(2011) states,
"In truth however, willing (wanting, the voluntariness involved in our actions), is neither a mental act one performs nor something that happens to one; it is neither voluntary nor involuntary, neither action nor passion."
Hacker goes on to describe various accounts of 'willing', including his own. He does not however (at least, to my reading) provide any example of an instance of willing which lies in a realm other than voluntary or involuntary, and I find it impossible to conceive of such an example.
I acknowledge that a decision might be deemed to be different somehow to an act of will, but the two concepts seem close enough to merit close attention and that Hacker's point - if true - could well knock my argument dead.
So:
Can a decision be something other than voluntary or involuntary? And, if so, what might be an example of such a decision?