Saturday, July 14, 2007

Birds, frogs, pasta, and the ultimate nature of reality

Things I'm reading instead of what I should be reading: Max Tegmark's new paper, The Mathematical Universe, which expands on his earlier work that I've mentioned before.
The External Reality Hypothesis: There exists an external physical realitycompletely independent of us humans.

The Mathematical Universe Hypothesis: Our external physical reality is an abstract mathematical structure.
This is one of those "so crazy it might be true" theories. And for me, it seems to talk about some of the more abstruse issues in theoretical physics from the math up, in a way that makes them almost comprehensible.
When considering such examples, we need to distinguish between two different ways of viewing the external physical reality: the outside view or bird perspective of a mathematician studying the mathematical structure and the inside view or frog perspective of an observer living in it.

...If history were a movie,the structure would therefore correspond not to a single frame of it but to the entire videotape. Consider the first example above, a world made up of classical point particles moving around in three-dimensional Euclidean space under the influence of Newtonian gravity. In the four-dimensional spacetime of the bird perspective, these particle trajectories resemble a tangle of spaghetti...To the frog, the world is described by Newton's laws of motion and gravitation. To the bird, it is described by the geometry of the pasta, obeying the mathematical relations corresponding to minimizing the Newtonian action.

[under Quantum Field Theory]...If the bird sees such deterministic frog branching, the frog perceives apparent randomness.
I like those bird and frog terms and will adopt them for my own scruffy thoughts on the nature of subjective and objective views of the universe (I may leave out the pasta though).

Science is the process whereby frogs laboriously attempt to take the perspective of birds.

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