Across the series I can see tension from this question. In Booth, it is his need to provide hard evidence which will stand up in court, against his simultaneous gut feelings. In Brennan, it is her drive towards empirical truth - the dominant force of her mental character - against (I think) her acknowledgment that the scientific theory on which her empiricism is based is *not* the whole truth. Several times in the series she refers to the possibility that time may not be the linear stream that we perceive, and she also clearly recognises the consequences of quantum theory. One of these is Schrödinger's Equation, which (as I understand it) says that every particle of mass in the Universe occupies the entire Universe (i.e. we are all everywhere) - there is just a probability attached to a particular particle being in any one space-time location. So the 260 bus service from Ardmore to Cork might arrive on the Moon - but that is a *very* low probability. A far higher probability (close to 1!) is that it will arrive in Cork - but we can't be absolutely certain.
Brennan actually has the same "gut" problems as Booth, she just acknowledges them differently. Booth says "instincts" and Brennan has a recognition that scientific theory is not yet complete - she does not yet know the full truth that she yearns for, so cannot form absolute concusions.
I was glad to see Cyndi Lauper back as the psychic - for me, she fits right into the role - and I think she obviously personifies this central dichotomy. I was sorry that she only got three more reappearances in the series. And I wish they had made more of her singing talent while they had her!