BB,
I would sure like to know what it was, though!
I'm thinking maybe the brain has developed abilities to read other peoples thoughts, evolution may have hit on it as it would be a definite advantage for survival of the fittest to pass on in their DNA.
I think also the probability of universe being simulation and the Many Worlds Interpetation many offer some possible explanation.
To be an extreme materialist leaves only a narrow window to look at the world, it is good to leave a little more room for explanations of these things, Many Worlds, and a computer simulation hypothesis may be something a materialist could use if they loosen up a bit.