Eddy Nahmias explains why if you’re going to argue free will doesn’t exist, we better make damn sure we’re all talking about the same thing:

The sciences of the mind do give us good reasons to think that our minds are made of matter.  But to conclude that consciousness or free will is thereby an illusion is too quick.  It is like inferring from discoveries in organic chemistry that life is an illusion just because living organisms are made up of non-living stuff.  Much of the progress in science comes precisely from understanding wholes in terms of their parts, without this suggesting the disappearance of the wholes.  There’s no reason to define the mind or free will in a way that begins by cutting off this possibility for progress.

Our brains are the most complexly organized things in the known universe, just the sort of thing that could eventually make sense of why each of us is unique, why we are conscious creatures and why humans have abilities to comprehend, converse, and create that go well beyond the precursors of these abilities in other animals.  Neuroscientific discoveries over the next century will uncover how consciousness and thinking work the way they do because our complex brains work the way they do.

Philosophers and scientists alike, take heed: define what it is you’re talking about. Don’t presume shared jargon.