She was arguing now, Thomas realized, not simply entertaining academic claptrap for the purposes of tracking down Neil. The Argument had a way of doing that to people. He could remember the horror it had engendered in him years ago in Skeat's class. The sense that some kind of atrocity had been committed, though without date or location. More than a few times he and Neil had made the mistake of debating it while catastrophically stoned—a mistake for Thomas, anyway. He had simply sat rigid, crowded by paranoias, his eyes poking and probing the tissue that had once been his thoughtless foundation, while Neil had laughed and chortled, pacing the room as if it were a cage. Thomas could see him, hair askew, ducking to peer into his face. 'Whoa, dude… Think about it. You're a machine—a machine!—dreaming that you have a soul. None of this is real, man, and they can fucking prove it.'

Thomas rubbed his eyes. 'In controlled circumstances, researchers can determine the choices we make before we're even conscious of making them. The first experiments were crude and hotly contested—pioneered by a guy called Libet. But over the years, as techniques improved and the fidelity of neuro-imaging increased, so did the ability to pin down the precursors of decision making. Now…' Thomas trailed with an apologetic shrug. 'What can I say? People still argue, of course—they always will when it comes to cherished beliefs.'

'Free will is an illusion,' Sam said in a strange tone. 'Even now, everything I'm saying…'

Thomas swallowed, suddenly apprehensive. He had been carefully folding his napkin as he talked; now he set it like a tiny white book on the table before him. 'Only a small fraction of your brain is involved in conscious experience, which is why so much of what we do is unconscious. The bulk of your brain's processing falls outside what you can experience; it simply doesn't exist for your consciousness, not even as an absence. That's why your thoughts simply come out of nowhere, apparently uncontrolled, undetermined… Yours and yours alone.'

Samantha yanked her hands out in a warding gesture, shook her head. 'Come on, professor, this is just too crazy.'

'Oh, it goes deeper, trust me. Everything falls apart, Agent Logan. Absolutely everything.'

Sam watched the streamers of bubbles in her beer. 'So it has to be wrong, doesn't it?'

Thomas simply watched her.

'Doesn't it?' she repeated, her tone somewhere between wonder and irritation.