Pensieve Flashbacks are not just a metaphor of how he's deducing what happened; he's really projecting himself in the past once he has enough elements to focus on the specific case. Note how deep in a trance he can end up; it sometimes takes yelling at Murdoch to snap him out of it. Besides, he did see the ghost of the murdered twin at the end of "Belly Speaker", further clue of psychic sensitivity. This also explains why so many of his inventions are ahead of their time: he's literally channeling the future to get his revolutionary ideas. This capacity getting out of hand explains all the events in The Murdoch Effect; after getting knocked unconscious, he literally projected his mind into the future. Maybe not a literal future — the And You Were There aspect of it, as well as the similarities to the actual case he was investigating in the 1890s hint that it was still All Just a Dream. Nonetheless, it was his power to catch glimpses of the future going into overdrive that allowed him to see 2012 Toronto as it is. He didn't need Crabtree to be the one knocking him out, of course; it was just the way he imagined it needed to be done.