Constructing Stuff

Constructor theory

My friend asked me to look into constructor theory because he knows I'm interested in nonmathematical  popularizations of physics. He finds the concept quite interesting but since he's currently seeking a professorship and has a life, he lacks the time to check it out himself.  I had never heard of Constructor theory and it sounded really interesting, so I've been digging into it.  Here is my report to him.

Constructortheory.org says:   >Constructor Theory is a new approach to formulating fundamental laws in physics. Instead of describing the world in terms of trajectories, initial conditions and dynamical laws, in constructor theory laws are about which physical transformations are possible and which are impossible, and why. <



Interesting. However, too vague to be meaningful. Further digging revealed more detailed explanations.

The creator of the thory, David Deutsch says on the http://www.templetonworldcharity.org/projects/constructor-theory-of-information :
>The purpose of this project is to discover the single underlying explanation for all distinctive properties of information in Physics and beyond, which is at once the root of both the familiar properties of information, such as transcending specific embodiments, and its apparently paradoxical quantum-mechanical ones.
Our main innovative tool for addressing this is Constructor Theory, recently proposed by David Deutsch. This theory expresses all scientific theories in terms of a dichotomy between possible and impossible physical transformations - an audacious departure from existing fundamental physics (whose dichotomy is between what happens and what does not, given initial conditions).
Applying the constructor-theoretic approach to information theory, we have established the result that a simple constructor-theoretic property of the laws of quantum physics implies all the disparate features that distinguish quantum information from classical, thus revealing the hitherto mysterious connection between them. (Deutsch and Marletto, 2014)
Building on these results (Marletto, 2015), we have also addressed the issues of whether and how certain properties of living entities, such as the ability to self-reproduce and replicate, can be possible under no-design laws of physics. One shows that they can, provided that those laws allow, in addition to enough resources, information media, as characterised in the constructor theory of information.
Our work is now focussed on two projects,“Constructor Theory of Testability” and “Constructor Theory of Probability”. The latter generalises the well-known arguments to show how the Born Rule can emerge in unitary quantum mechanics, un-augmented with additional probabilistic postulates. Our constructor-theoretic generalisation depends on fewer and much simpler axioms, which are better motivated physically and are now expressed in an information-theoretic form. The Constructor Theory of Testability uses this argument to show that Unitary Quantum Theory is testable against rival theories. A new strand of research in the direction of investigating the properties of superinformation media has also emerged, using the information-theoretic tools of constructor theory to explore the information-theoretic properties of quantum media – chiefly, the possibility of teleportation  – regarding quantum systems as a special case of superinformation media.<


This sounds like Deepak Chopra; very high sounding language which seems to convey zero meaning.

So I began looking for a more practical, understandable, popularized explanation. You know, something within my range of comprehension.

Things seemed to make a lot more sense at this level.
The idea is that rather than establishing complex sets of rules and laws to predict or describe outcomes, physics should turn to a simpler, more fundamental concept which would underlie those rules and laws.  In the fact they were seeking the E = MC2 (I can't figure out how to get that two little and floating… Oh well, you know what I mean) that underlies all physics. A simple concept, easily expressed which then leads to the much more complicated world when it is applied to reality.

This is a very exciting concept. Many scientists and mathematicians are deeply enamored of the belief of beauty in simplicity. They are convinced that complex descriptions of reality must have an underlying simple and easily understood beauty and symmetry.  Constructor physics promises to be that theory of everything which starts so simple and clear and only becomes complex in application.

I must question the sweeping level of these promises. I always tend to be suspicious when you get this level of conviction.  As one advocate website has it, "Only a fool would bet against the possibility that constructor theory could also become a mainstream idea in physics that will have profound consequences for our future understanding of the universe."

Well I certainly don't want to be a fool,  but is it really foolish to engage in the usual scientific procedure of doubting any new theory until it is conclusively proven?  This kind of enthusiasm strikes me as an attempt to poison the well of anyone who dares to doubt.  It the theory is that wonderful, why the need to denigrate those who question it?

A critic ( http://motls.blogspot.com/2014/05/constructor-theory-deutsch-and-marletto.html) says, >What is this constructor theory? It's a sequence of worthless would-be smart sentences sold as a "theory of everything" and a "unifying theory of classical and quantum physics" and "all information in them" which also "defines all forms of information" and transforms all of our knowledge to "claims that some tasks are impossible"....

Some of the most experienced readers already know that
a kettle may heat water.
Fortunately, the authors allow us to formulate even such statements in a more "natural" and more "profound" way:
For instance, a kettle with a power supply can serve as a constructor that can perform the task of heating water. <

This is where the theory loses me, although supporters seem to enjoy this example with particular delight.  So,  a kettle becomes a constructor of bumps if I grab it by the handle and use it to hit someone in the head?  If he chooses to fight back, is the kettle now a constructor of fistfights?  Might it  even become the constructor of a restraining order?

Is this really physics?

The worst criticism of this concept from my point of view is that after all, it describes things that it says are impossible. However, it offers no proof that they are impossible, unless you include the laws which are supposed to be derived from this theory. In practice this means that the theory is simply describing something that the laws have already established. The laws come first, they are not derived from the theory as advertised.

As exciting as I found the idea originally, as I researched it and thought about it, my opinion has settled into believing that this is merely an elaborate linguistic construction.  I'm reminded of the endless ramblings of Wittgenstein.  It is easy to confuse reality with language, but language is only descriptor of reality, not the thing in itself.

Sadly, I have to turn away for what I thought at first was an exciting new idea. When it comes to theories that cannot yet be fully tested, perhaps not even deeply tested, I'll stick with string theory.

My response to Bobby's post

5.6 The limits of my language are the limits of my world.

Pinker refers to a Mexican man born deaf. Desperately poor, he never learned a language, not even a sign language. As an adult he finally became lingual. He is reported to have stated that he was able to clearly without words, suggesting that language is more a tool than a defining framework of reality.

Extreme deconstructionists have carried Wittgenstein's concept to the level in insisting that technologically primitive people could not even see things which were beyond their language limits. Thus, I suppose, the conquistadors were first seen as floating in the air, since the concept of a rideable draft animal was unknown to the locals. Said locals actually referred to the horses as god dogs. Horses may have been outside their language, but they adapted what they knew to a new concept. Large sailing ships were referred to as floating islands or clouds [due to the billowing sails]. I expect things like guns and steel swords were also invisible...

5.61 Logic fills the world: the limits of the world are also its limits

Only for those dedicated to logic. Most people find logic uncomfortable and alien to their thought processes.

What we cannot think, that we cannot think: we cannot therefore say what we cannot think.

So, since such things have not existed since, or even before, the evolution of humanity, there can be no internet, computers, cars, space stations, sculpture, etc.

5.62

Actually, I think you just said what you said you could not say.

5.621 The world and life are one.

Not sure what he means by this. In the light of the solipsism remark, I assume he means that to each of us the world exists only as long as we live to perceive it. Fair enough, but unless we are all horribly insane and impose suffering upon ourselves, the world nevertheless imposes a reality upon us which is independent of our perceptions. We may not be aware of it until it enters out perception, but it is there.

5.63 I am my world. (the microcosm).”

Maybe, but you don’t control your world. The world which apparently doesn’t exist except in your perception of it imposes perceptions upon all of us, you included.

6.4312 The temporal immortality of the soul of man...

Clearly outside of the area of scientific inquiry. Therefore not amenable to proof. One believes or does not. I am convinced that we believe based upon emotional reactions and then rationalize that belief after it is confirmed and established in our thoughts.

6.432 How the world is, is completely indifferent for what is higher. God does not reveal himself in the world.

“If you do things right, no one is sure you have done anything at all.” God’s ending soliloquy to the audience in a Futurama episode in which Bender is God, well a god, for a while.

6.4321 The facts all belong only to the task and not to its performance.

I have no idea of what this means. I can guess, I suppose, that this is related to Kant’s thing in itself (German: Ding an sich). That is, the facts are real and are what they are regardless of our perception or interpretation. But is that what he means by “performance”? You're the one who started all this, explain it to me, please.

6.44 Not how the world is, is the mystical, but that it is.

Fair enough. The very fact that something exists has puzzled the human race for at least millennia. Before the invention of writing who knows if it bothered our ancestors? It seems likely, but how could we know?

6.45 The contemplation of the world sub specie aeterni is its contemplation as a limited whole. The feeling of the world as a limited whole is the mystical feeling.

Had to look up “limited whole” and found too much info to absorb in time for this response. Still, it seems that Wittgenstein’s point is that since we are a part of the limited whole, we cannot logically explore those limits. Only thorough the mystical can we perceive, even conceive of our reality as a complete reality. From my point of view, this fits within my acceptance of an understanding of a reality which is not directly subject to logical or experimental testing.

6.5 For an answer which cannot be expressed the too cannot be expressed. The riddle does not exist. If a question can be put at all, then it can also be answered

Reminds me of my take on so called paradoxes. Actual paradoxes do not exist. There are only false paradoxes which are created by poor use of language and postulations of impossible events. For example, “Which came first, the chicken or the egg?” A silly question. If you believe in special creation then you believe, Now the LORD God had formed out of the ground all the beasts of the field and all the birds of the air. He brought them to the man to see what he would name them; and whatever the man called each living creature, that was its name.Genesis/2-19. Clearly the chicken came first.

If you believe in evolution and science, then eggs predate chickens by many millions of years.

Either way, the question, this great paradox, is silly and nothing more than a poorly worded statement of mental confusion. It is so with all paradoxes, great and small.


6.51 Skepticism is not irrefutable...

I am not so certain that every question has an answer. This smack to my ear of the special pleading used by St. Anselm. Since God is perfect, He must exist, since not existing would not be perfect. Again, like the paradox, this is more about careless thinking and mistaking language for the reality which it is attempting to describe.


6.52 We feel that even if all possible scientific questions be answered, the problems of life have still not been touched at all.

Again, this is comfortable to me, with my insistence that there are two epistemological realities. One dealing with the real as studied and known by science and the other open to the spiritual and the mystic. I am not cetain what he means by the final phrase, Of course there is then no question left, and just this is the answer. The “just” seems out of place. Take it away and I am again comfortable with the statement.

6.521 The solution of the problem of life is seen in the vanishing of the problem

Yes. Again, there is a path to another reality, one which is not testable or measurable, but which is, nonetheless, knowable and accessible via meditation and transcendence.

6.522 There is indeed the inexpressible. This shows itself; it is the mystical.

In the words of my youth, “Right on!”

6.53 The right method of philosophy would be this.

This seems in direct contradiction to what has already been said. It is deliberately self contradictory even with in the statements, so I assume this is deliberate, but I fail to see the point. Demystify, please.


6.54 My propositions are elucidatory in this way:

If we must throw away the ladder and rise above the limits of what was taught, why teach it in the first place? Is Wittgenstein saying that this is the
only route to transcendence? That we must tread the path of plodding realism to reach a point from which we can then metamorphose into a higher and better perception of reality?


7 Whereof one cannot speak, thereof one must be silent.

So what is that of which Wittgenstein cannot speak? Does he see it as real or more profound than real [realer than real?] Is there value in attempting to speak about things which are beyond words? I cannot give anyone the feeling I have of oneness and completion and love that I feel at the best of my meditations, but I can refer to the numinous and give others a sense of what I fell. Is there not value in that?

Last time we spoke of Wittgenstein, I was sitting at the desk in my youngest daughter’s home and my grandson was tugging impatiently at me as I was not paying attention to him. There is irony in that as I am now not allowed to see him or his siblings until and unless I disown my other children and grandchildren. How strange life is.

I have never had the patience to deal with Wittgenstein. His ideas are interesting, but I find his writing of inferior quality. He does not explain what he means effectively. It is good that you bring these things up, because it exposes me to that which I would otherwise ignore.

That last time I wrote to you about W, I quoted Monty Python, “Wittgenstein was a terrible swine.” I must correct myself, the actual quote is, “Wittgenstein was a drunken swine.” Wouldn't now about that, but he was a lousy writer.

Almost 5 am. Feeling very nauseated and confused. Time to post and sleep. I miss you, Bobby.

Bobby's post

Wittgenstein's Monster
by "http://www.facebook.com/LostWinter" on Sunday, August 19, 2007 at 12:55pm
So, I finished Wittgenstein's Tractatus this summer. Much of it not written for a general audience, I had to reference a lot of stuff from Russell and Frege (and Whitehead) to make sense of the analytic philosophical arguments of the era. But, alas, I got through.
The ending takes this surprisingly mystical turn (and certainly why Russell disagrees with it). It's without a doubt, my favorite part (sorry Russell old chum), and worthy to chew on for awhile. So, I thought I'd transcribe the last 2 pages and let anyone else munch with me. Enjoy.

“5.6 The limits of my language are the limits of my world.
5.61 Logic fills the world: the limits of the world are also its limits. We cannot therefore say in logic: This and this there is in the world, that, there is not.
For that would apparently presuppose that we exclude certain possibilities, and this cannot be the case since otherwise logic must get outside the limits of the world: that is, if it could consider these limits from the other side also. What we cannot think, that we cannot think: we cannot therefore say what we cannot think.
5.62 This remark provides a key to the question, to what extent solipsism is a truth. In fact what solipsism means, is quite correct, only it cannot be said, but shows itself. That the world is my world, shows itself in the fact that the limits of the language (the language which only I understand) mean the limits of my world.
5.621 The world and life are one.
5.63 I am my world. (the microcosm).”


6.4312 The temporal immortality of the soul of man, that is to say, its eternal survival also after death, is not only in no way guaranteed, but this assumption in the first place will not do for us what we always tried to make it do. Is a riddle solved by the fact that I survive forever? Is this eternal life not as enigmatic as our present one? The solution of the riddle of life in space and time lies outside space and time. (It is not the problems of natural science which have to be solved.)
6.432 How the world is, is completely indifferent for what is higher. God does not reveal himself in the world.
6.4321 The facts all belong only to the task and not to its performance.
6.44 Not how the world is, is the mystical, but that it is.
6.45 The contemplation of the world sub specie aeterni is its contemplation as a limited whole. The feeling of the world as a limited whole is the mystical feeling.
6.5 For an answer which cannot be expressed the too cannot be expressed. The riddle does not exist. If a question can be put at all, then it can also be answered.
6.51 Skepticism is not irrefutable, but palpably senseless, if it would doubt where a question cannot be asked. For doubt can only exist where there is a question; a question only where there is an answer, and this only where something, can be said.
6.52 We feel that even if all possible scientific questions be answered, the problems of life have still not been touched at all. Of course there is then no question left, and just this is the answer (!!!! I like that part).
6.521 The solution of the problem of life is seen in the vanishing of the problem. (Is not this the reason why men to whom after long doubting the sense of life became clear, could not then say wherein this sense consisted?) (I like that part too: )
6.522 There is indeed the inexpressible. This shows itself; it is the mystical.
6.53 The right method of philosophy would be this. To say nothing except what can be said, i.e. the propositions of natural science, ie something that has nothing to do with philosophy; and then always, when someone else wished to say something metaphysical, to demonstrate to him that he had given no meaning to certain signs in his propositions. This method would be unsatisfying to the other – he would not have the feeling that we were teaching him philosophy – but it would be the only strictly correct method.
6.54 My propositions are elucidatory in this way: he who understands me finally recognizes them as senseless, when he has climbed out through them, on, over them. (He must so to speak throw away the ladder, after he has climbed up on it.) (!!!) He must surmount these propositions; then he sees the world rightly.
7 Whereof one cannot speak, thereof one must be silent.

Damn.
If anyone wants to talk about this or other Wittgenstein, I'd love to.