His argument appears to be that since we cannot see how we make decisions, we are just witnesses to our decisions, and therefore we do not make the decisions ourselves.
I get it, but I don't agree.
The ability to inspect the decision making process is inherently absent from neural networks. That is the nature of the beast.
A neural network is not like a programmed, serial processing machine (a "computer"), which in the old days you could instruct "TRON" ("Trace On"), and the machine would show each step of the decision, identifying each line of code that led to each part of the decision...and you could track each memory access to a specific location of memory storing specific data. It had steps in the decision which were traceable. The structure had specialized components very different from one another, which facilitated tracking of functions ("decision making").
But, a neural network is not serial; it is massively parallel. Our brains perform massively complex operations in parallel, and produce an answer/decision almost immediately. There are no steps to trace. All data is put in at once, and decisions are just arrived at. The decision is your free will in action (assuming for a second). Or it is not. But the ability to monitor the process and dissect it seems irrelevant to me as far as the issue of free will is concerned.
Decisions come from the structure of our brains, and we can change that structure solely with thought. We can decide to reinforce certain pathways by making internal decisions to think certain ways. We make our brains as we think. Choices we make today do effect choices we make tomorrow (because the structure of our brain is changed with every choice), but that is an example of our will (free or not). I don't think the structural nature of our decisions is evidence against free will.
To me, it all comes down to this: Are we purely causal beings, or not. Are the ions in our brain just billiard balls on the universal billiards table, responding to the break that was initiated by the universal cue ball which caused the Big Bang? Or do we have freedom from the causality we see around us?...the causality that is the very foundation of science? Personally, I think the answer is potentially unknowable to us. There is perhaps a better argument for no free will, because free will requires belief in something non-physical/non-causal. And yet, we believe in self-awareness and consciousness because we perceive them. They are tied to the physical brain, but we perceive them at a higher (non-neuronal) level. We also perceive free will, rightly or wrongly (and it is admittedly tied to a healthy brain). We feel like we are deciding. Maybe that is good enough.