Lee Smolin: Information and Computation

Firstly:

“LEE SMOLIN, a theoretical physicist, is a founding member and research physicist at the Perimeter Institute in Waterloo Canada. He is the author of The Life of The Cosmos and Three Roads to Quantum Gravity.“

In his talk, Smolin offers observations from the cross-section of what we define to be computation and what we know of physics (a greater understanding can be obtained from his writings, specifically he seems in this video to refer to notions from this paper).

Three types of physicist; those that believe in a universe that computes through the migration of “information,” those that have no idea what the hell that means and those that also have no idea but assume that a computational universe perspective might do well for the field of physics. Smolin assigns himself to that latter of the three and proceeds to talk about evidence for such a perspective in the form of a Beckenstein Bound (BB) and the Holographic Principle (HP). Why would looking at physics as computation be helpful and what does the BB and HP have to do with all of it?

The BB and HP states (among many other things) that if 4 bits of information per Planck’s area (10^{-66} meters^2) on a surface were exceeded then we would essentially cross the lines drawn by the 2nd law of thermodynamics. Meaning, we are dealing with a finite amount of information. This is a big deal! It means that there is a boundary to the amount of information in the universe (or “this universe” depending on your viewpoint) and given sufficient means we could theoretically model certain aspects of the universe or anything in it once we can quantify it…and we COULD quantify it because as the BB and HP assert, there is a boundary on the amount of information within a given space — there is a finite amount of quantum variability.

Further, we find that if looking at the universe as computing information then we might find that what we know to be Euclidean geometry or any geometry for that matter exists as derivative of this computation. Like geodesic movement is a result of this + this if that or else that if this is of course that. Yet this could sound very far out or very obvious and in tune to what we are accustom — because we have equations that quantify things in spacetime and if I take this over that times this, etc we could draw the resulting figure with our pencils and say “this is where Venus will be on September 14th, 2007.” However, that would be our calculation and not the Universe’s. We seem to be satisfied when calculating the movements of planets, apples, cannon balls and such because things seem to occur just like we calculate them to be. Yet, when we talk of calculating things in the quantum world (which no doubt causes the effects we see in the macro-world) we are confined to the fuzzy spaces of quantum fields and things become quite uncertain, so uncertain there is a name for it: The Uncertainty Principle.

So once again, what good does a computational universe, BB and HP provide physics? Well, if we assume each and remain within the realms of reality then we are saying that we can model portions of the universe by first accepting the information in the universe as finite and that there is an algorithm out there waiting for our use in our quantum models and when such we no longer have to be uncertain as a principle — all we would have to do is model, simulate and check out the logs so to speak. However, this may only yield acceptable results and never exact precision because it may require us to model the entire universe, which doesn’t seem possible without using the entire universe. Yet with a little compression and negligence to accept less than precise answers we can still do away with most of the quantum uncertainty.

Anyway, I have read The Life of The Cosmos and recommend it. Lee Smolin as, Murray Gell-Mann puts it, is

“…that young guy with all those crazy ideas…He may not be wrong!”