Thanks to Vijay for a thought provoking post. I like the juxtaposition of quantum gravity and neuroscience. I think that it carries two messages, one trivial a

Thanks to Vijay for a thought provoking post. I like the juxtaposition of quantum gravity and neuroscience. I think that it carries two messages, one trivial and one deep. The trivial one is that physics builds on the human nature to build concepts. Both a jaguar and a quark are ideas that we extract from our perceptions, that we share with others and that help us to model and predict the world - quarks just need a more expensive microscope like the LHC. Sure eagles and prawns may have slightly different versions of concepts since they have different colour perception, but only marginally so. A practical fellow like a physicist will be clear that when the concepts can make measurable predictions they are worthwhile (we call this meta concept "real"). It is not possible to store the full state of or compute the evolution of anything macroscopic to full precision - such as the positions and momenta of all the particles in a table. So concepts are the only things we can know about reality. They argue that we may never be able to attain the deep underlying reality - either because it is theoretically unattainable or that we will continue to be resource limited. I contend that this dichotomy is false. It just may never be possible to attain deep underlying reality. The best we can do until we get there is to find some probabilistic rules that work in a pragmatic sense and to refine these tools over time. [That's pretty much a restatement of the Copenhagen interpretation of 1922]. The deep one is that we are probably looking down the wrong end of the telescope. As far as I can tell (from popular neuroscience) is that our ability to model the perceptual / conceptual processes and how they compose into intelligence remains in the dark ages. But, given that we each have 70 billion neurones or so, there is a lot of classical physics going on in our heads to make these concepts and we have practically no hard, proven theories about how this works. We are doing layers of pattern recognition and extraction and feedback that allows us to avoid being eaten by Jaguars. So let's get a proper theory of intelligence. One that let's us work out which aspects of quantum mechanics are philosophically necessary to sustain our subjective experience of space and time. With a substrate with branching / collapsing features. Where time has an arrow with memory in the past and uncertainty in the future. Where cause and effect are loosely coupled. Where there is a notion of free will. Some endnotes: - The quantum measurement problem is perhaps a limit of this theory - Perhaps the notion of computational reducibility is a stab in this direction [Wolfram] - Probably all you need is emergence for this and not a quantum brain [Penrose]