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When Does the Universe Compute?
KentuckyFC writes "The idea that every physical event is a computation has spread like wildfire through science. That has triggered an unprecedented interest in unconventional computing such as quantum computing, DNA computing and even the ability of a single-celled organism, called slime mold, to solve mazes. However, that may need to change now that physicists have worked out a formal way of distinguishing between systems that compute and those that don't. One key is the ability to encode and decode information. 'Without the encode and decode steps, there is no computation; there is simply a physical system undergoing evolution,' they say. That means computers must be engineered systems based on well understood laws of physics that can be used to predict the outcome of an abstract evolution. So slime mold fails the test while most forms of quantum computation pass."
"I'll get it," a wife said to her husband as the phone rang.
On the line a pervert, breathing heavily, said, "I bet you have a tight asshole with no hair."
"Yes," she responded. "He's sitting next to me watching TV."
The type of computation discussed in this article is not the type of computation used in the phrase "every physical event is a computation". These physicists are trying to discern computation from physical processes by discerning whether the process can encode information in its initial conditions, and other information can be extracted from its results. This is good when trying to determine which processes lend themselves to building computers, but it does not address the question of whether the universe is a computer, and whether the laws of physics are merely closed form equations describing some of its operational semantics.
Higher Logics: where programming meets science.
For example, the processes that slime mould uses to solve a maze are largely unknown. For this reason it is not computation.
Don't we usually declare characteristics of things based on what we know about them, rather than on the basis of not knowing about them?
Seems like a strange kind of subjective solipsism--"what is, is dependent upon on what I currently know is".
~ Whence do you come, slayer of men, or where are you going, conqueror of space?
Point particles come from the interaction of various waves which carry force. Points don't even take up space. The Universe is one giant 2D wave, and all 3D space is holographic illusion.
Look, seriously, Doom was DECADES ago at this point. The rest of the world's moved on, you really need to stop living in the past and base your universal theories on something OTHER than an engine Carmack made back in the DOS era.
Maybe not *your* balls.
Actually, he's right, and the analogy is quite good too. Newtonian physics is "wrong" in the sense that it doesn't hold for very massive, very fast or very small objects. However, for medium-sized objects moving at medium speeds, it holds very well.
Similarly, the second law of thermodynamics, that entropy always increases, can be derived in statistical mechanics by assuming that there are an infinite number of particles in your system. Thus, it holds for the entire universe, and it holds extremely well for any macroscopic system that I know of. However, for microscopic systems, it becomes quite probable that entropy decreases in small periods of time (the fluctuation theorem tells you the probability for this to happen.)
If you're interested in how this "makes sense": in statistical mechanics, it is shown that entropy is actually just a measure of microscopic disorder. There usually exists a lot more of possible disorderly states than orderly states for a system, so if no particular microstate is preferred (the probability of entering any microstate is equally probable), it's simply more probable that you will observe a transition from an ordered state to a disordered one, not the other way around. For a small system, the discrepancy is small, so you see transitions in both directions on small enough timescales. But as the number of particles in the system grows, the number of disordered states of the total system will grow far faster than the number of ordered states (the discrepancy is O(n!) for n particles in the system), so transitions from disordered to ordered states become extremely unlikely.