What do you believe, but can't prove?

Jason Kottke points out a thread at Edge on their World Question for 2005, asking leading intellectuals: What do you believe but cannot prove?
A number of Kottke's favorites are on his site. After the jump: some of my my faves from the Edge site, as well as a few beliefs of my own.

Robert Trivers
...Processes of self deception are important in limiting the achievement of individuals.

Anton Zeilinger
...Quantum physics teaches us to abandon the distinction between information and reality.

Marti Hearst
Advances in computational linguistics and user interface design will eventually enable people to find answers to any question they have, so long as the answer is encoded in textual form and stored in a publicly accessible location.

Randolph Nesse, M.D.
I can't prove it, but I am pretty sure that people gain a selective advantage from believing in things they can't prove.

All in all, a wonderful read.

Some of my own:

I believe, but cannot prove, that some genetic or epigenetic change occurs to living organisms during their lifetimes and is passed on to their offspring, maybe through a process of selection during the fertilization process. This is written off as Lamarckian by modern scientists, but I believe it is a small but critical part of the evolutionary process. Mutation is less random than is currently supposed.

I believe, but cannot prove, that human beings have many undocumented instinctual behaviors, both as children and as adults.

I believe, but cannot prove, that a human will one day create an algorithm which could recreate our universe exactly. But I don't think it will just be numbers.