Is the Universe computing something?

Ok, we assume that initial data input contained all the energy, then you are making the universe as perpetual machine ? Or this massive computer's energy requirement is diminishing as time passes ? Because energy is getting consumed in every computation ? This does not fit in.

 

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Does that not have something to do with Entropy?

 

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Taking one rock from the sack involves some pretty complex energy exchanges, but that is all that ever happens in this universe, and for the most part, the state of the rest of the universe remains unchanged by that activity.

Does a computer really do anything that is different?

 

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Only in the sense that we identify certain possible future states of a computer with computations. For most systems, there is no identification. This is a mental exercise.

 

A computer does not compute, though it appears that a computer is computing. A computer is designed by a mind. Computer responds or works as per this design. Change the design and the computation of a computer will change. So, a computer simply responds as per its design.

 

The rock warming in the sun is an interaction. This interaction is not haphazard or random but happening as per some Physical Laws of our Universe or Nature. Our Nature or Universe responds through some Physical Laws.

 

How exactly does any of that refute the notion that a computer does indeed compute?

 

Because a computation, or calculation, is a mental activity. We design physical computers to perform a series of state changes that we identify as analogous to the mental activities that are part of a computation. In the end, if they operate within certain tolerances, physical computers produce a result that we can then interpret as the result of a calculation.

 

Ok, what you're saying is that computers are extensions of human mental activity; perhaps any kind of tool we make or have ever made is in this category.

But that really only shifts the question: why do humans design and build computers, or any kind of tool? Why is it that humans can build computing machines? It must have a close connection to the way the universe works. Once we start building quantum computers, the reasons (we build computers) will be even more closely connected to the universe and how it works, fundamentally.

 

The reasons that we can do this is laid out quite nicely in the original Turing paper. When we want to do a calculation, we want to do something mentally that is without creativity, that follows a strict chain of steps. We can make physical systems, to some extent, follow cause and effect in a way that matches the expectations that we have for these steps.

 

Another comment I'd like to make is about what we mean today when we talk about computers. These are and always have been classical devices, even quantum computers only compute something because there is a way to get a classical output--any quantum experiment is 'embedded' in a classical way, an interferometer is a classical device.

So this implies that, if the universe is a computer, it must have classical outputs. The 'circuitry' need not be classical as we also know.
Suppose the computer doesn't have any classical output, how can we ever know it's computed something?

 

I agree on that point. But the OP asks if the universe itself is a natural computer and the output is what we can observe as reality.

 

We would first have to define what 'non-classical output' might be.

 

So, we could stretch the definition of computing to the functions of the universe. HOWEVER.......
The input of a universal computer are *random* probabilities of certain computable inputs, such as the inevitable probability of two negatively charged electrons bonding with a positively charged proton, creating an output of an Hydrogen atom. But this cannot be considered any form of intentional computing to achieve a defined output. It is a mathematical processing of random available values, in accordance with the four fundamental inherent properties (potentials) of all things. The potential contained in the fabric of the universe itself imposes permittive and restrictive processing of information (values).

 

You bet it is.

Few physicists pause to reflect (pun intended) on what it means when a plane mirror makes the angle of incidence equal to the angle of reflection each and every time. This is the action of the outermost electron shells of metallic (aluminum, silver, or other) atoms deposited on one surface of the mirror, but it works just as well in the reflections of images from the surface of a still pond. What wonderful precision is that? Same kind of precision that makes objects as massive as the Sun or the moon or the Earth a smooth sphere, or their respective orbits ellipses. And whether we can calculate the trajectories of n-body problems or not, nature computes them all with perfect precision just fine without a degree in math.

Yeah, you could think of the universe as something that calculates various intermediate partial results of whatever set it all in motion.

As someone has already pointed out, it also set our minds in motion, optimized them to whatever they are, and that in turn allowed us to create computers and simulate all of the above to make predictions that will help us do whatever the next step in the process might be. All very natural.

 

I agree completely with that analysis.
My point was that this universal computer (Tegmark) does not *necessarily* require a supernatural computer tech (sentient causality), but also can function in a probabilistic *non-sentient* abstract mathematical context of values, natural equations and functions.

 

Modern day computer has evoloved from abacus. Todays computers use transistors. These transistors act like an electrical switch. They need external power source for their operation. When the external power source is there, these switches are in either ON(1) or OFF(0) states. Computer processes the information through boolean algebra.

Now, does our universe need any external power source for its operation? Does the universe follow boolean algebra? Is the universe digital or analog?

Our universe just responds. At every moment of time the universe is responding. In the absence of external power source, the computer will just stop working.

So, response of the universe can not be compared with the computing of a computer.

 

One doesn't need to appeal to an external power source. One can imagine a computing machine that requires no power. But the universe cannot match even this magical computer because there is nothing in the computer to recognize different states, respond to these states accordingly, and to provide a different output state. The universe just goes along its merry way. We might be tempted to identify the initial state of the universe as the input and the final state of the universe as the output, but these states are undifferentiated: they cannot be other than they are. And because they are undifferentiated, they cannot have the proper content to count as different states for the purposes of computing.

 

and what would be that ?? Any machine which changes states needs power/energy.

 

We could model various aspects/observations/phenomenons of universe, to a very high level of precision, Physics is intact, we can predict lot of things, universal constants are there.......they all suggest intelligence, massive intelligence, which we generally associate with computers...so question is very pertinent in that sense....