Quantum information storage in atoms

In a previous post I explained a little about why Seth Lloyd said that anything can be a quantum computer if you shine the right kind of light on it. Quantum information can be stored in electronic states of atoms. Those states might in principle be used for quantum computation. And those states can be manipulated by shining light on the atom. A more complete account can be found in these lecture notes. This post will be a very short summary in which I indicate some of the physical effects taking place in atoms. The subject overall is very complicated and mathematical so I can’t do much more than summarise it in a blog post.

A stable state for an electron around an atom is one in which its expectation values for measurable quantities don’t change over time. These states are states of constant energy and they form a discrete set that can be labelled by integers starting at zero, typically labelled by the letter n. The electron’s state isn’t fully described by how much energy it has, its orbital angular momentum also plays a role. The total amount of orbital angular momentum is labelled by another quantum number l. The orbital angular momentum in the z direction is also relevant and is labelled by another number m. Finally, an electron also has a type of intrinsic angular momentum called spin. The spin can only have two states and those a labelled by the letter s that can only take values -1,1. States of electrons around atoms are then described in terms of those values (n,l,m,s) that are called quantum numbers. Now, the amount of angular momentum an electron can have is related to its energy. Having angular momentum gives the electron energy. So an electron with a particular energy can’t have too much angular momentum or it will have more than is compatible with the amount of energy it has.

The electron’s stable states give probabilities for the electron to be in a given region. Those probabilities can be plotted in various ways, e.g. – drawing surfaces inside which the electron has some high probability of being found. There are websites full of such plots so I won’t reproduce them here.

Since the states I described are stable, and they are labelled by a discrete set of quantum numbers they an be used to store qubits. There are restrictions on how those values can be manipulated. If you want to change the values of the quantum numbers of an electron then are trying to change its energy and angular momentum, which are conserved quantities. So if you want to increase the energy and angular momentum, you have to shine light on the atom that is carrying the relevant amount of energy and angular momentum. And if you want the atom to drop to a lower energy and angular momentum state, the light has to be able to carry away that energy and angular momentum.

Manipulating atoms with light requires using coherent light: light where different versions of a photon are related to one another in controlled ways. This allows you to control the whether they arrive at different places at the same time or different times at the same place and that sort of thing. This requires using lasers. So researchers making quantum computers will try to pick atoms with transitions where the energy matches those available in relatively inexpensive commercially available lasers. It is also possible to arrange for photons to have a particular amount of orbital angular momentum with the right equipment.

Stefan Molyneux vs rational parenting

Stefan Molyneux is known among libertarians as an advocate of peaceful parenting (PP). PP is not the same as TCS and I thought I’d look at an interview he did on the topic and explain what’s wrong with his position.

I’m not going to explain everything, but I’ll pick a few things that stuck out as bad.

Before I say anything about Molyneux, I’ll post a few links about TCS:

http://fallibleideas.com/parenting-and-fallibility

Most parents make children do stuff they don’t like and tell a story about why they do this. The parent is coercing the child because the topic is important, e.g. – education, health. But then if the topic is important, it is important for the advice to be right and you ought to welcome criticism regardless of its source. So if you can’t convince your child of idea X that’s a criticism of X and you shouldn’t coerce him into acting on it.

TCS also has a theory of what’s going on when you feel emotionally coerced. Coercion involves a person acting on one idea while he has other ideas that he wants to enact and hasn’t resolved that conflict:

http://fallibleideas.com/coercion.

TCS claims that it is always possible to avoid coercion:

http://fallibleideas.com/avoiding-coercion.

TCS also claims that people are universal knowledge creators. A person can learn or create any knowledge that it is possible to create. See Chapter 2 of “The Beginning of Infinity” by David Deutsch.

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Molyneux states that spanking and raising your voice are violations of the non-aggression principle. But he doesn’t seem to have anything to say beyond that on philosophy of parenting.

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Molyneux recommends parenting books such as Parental Effectiveness Training. A quick look on Google reveals the following link:

http://parenteffectivenesstraining.blogspot.co.uk/2013/12/christmas-gifts-you-wish-they-hadnt.html

It’s about people buying gifts a child wants and his parents don’t want. It’s bad to want to prevent your child getting a gift he wants. Parents should want to help their children get more of what they like, rather than sabotage happiness.

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At about 22 minutes Molyneux sez he is willing to sacrifice some of his daughter’s privacy to tell stories about her that will help others.

This is very bad cuz sacrificing your child’s interests for any reason is a bad idea. The parent should offer guidance and resources that will help promote the child’s interests.

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Starting at about 24:00 somebody asks a question about what a parent should do when a child makes a rational argument to the effect that he should have more snacks or sugar. Molyneux replies by saying a person will sometimes feel ambivalent about the right thing to do. He sez that the tongue loves sugar but the belly likes less since you’ll get sick. So you have to go without stuff you want. He also relates a story where he denied his daughter a cookie because she had previously had hot chocolate.

So Molyneux does not think it is possible to live without coercion. There are some things you will be ambivalent about. And to deal with that you have to sacrifice.

Molyneux’s control over what his child eats is also bad. If you can convince your child not to eat something with arguments that might be okay if the child is interested in the arguments.

Also, being worried about diabetes over a cookie after hot chocolate doesn’t sound rational.

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At about 28 minutes he sez a parent should dictate to a child the way he would dictate to himself. He sez he heard that crack cocaine is good but he forces himself not to do it. He sez his test for making his child do something she disagrees with now is whether she’ll thank him later.

If you had an argument that persuades you that taking crack cocaine is a bad idea, then you wouldn’t be tempted by it. So saying you are tempted by crack cocaine is an admission that you have no such argument. And if you can’t come up with an argument against crack cocaine, you have to kinda suck as a philosopher. Crack is a waste of time that you could be spending learning interesting stuff and new skills.

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At about 43 minutes Molyneux sez that intelligence has a genetic basis. But people are universal knowledge creators, so genes can’t explain what a person achieves. Only his choices and ideas explain that. Molyneux also sez personality is fixed by the age of four. But personality is a result of ideas, including ideas about how to act. If those ideas are bad they can be improved at any age.

r/k selection political theory is rubbish

This essay has been touted by some people on the right as being a great explanation for liberal (lefty, not pro-liberty) and conservative political positions.

The essay is no good. The essay starts by describing a biological theory called r/k selection theory, which are related to how animals evolve under different resource constraints. I will mostly take the biological descriptions as accurate, except where they are in conflict with basic biology. I will also wait until the end of the post to explain that all biological explanations of behaviour differences between people are crap. The explanation is coming but I want to explain why I consider this specific analogy bad.

If there are lots of resources, then an animal will tend to breed a lot and take less care of its young. For example, rabbits in a field with grass might never be able to eat all the grass in the field. As such, they can make lots of offspring and if some get picked off it’s not a big deal for the rabbit’s genes. So the species in this environment of plenty will tend not to be interested in fighting or contending for resources. These animals will also be willing to sleep around because this results in more copies of their genes. This is called the r selection strategy.

The author of the essay then writes:

Since group competition will not arise in the r-selected environment, r-type organisms will not exhibit loyalty to fellow members of their species, or a drive to sacrifice on their behalf.

This is dumb.

First, no animal will sacrifice itself for a random member of its species. At most the animal will sacrifice itself for relatives who have some of the same genes. Genes are the unit of selection because they can be copied. A species cannot be copied and so is not the unit of selection. This is basic biology. The author could have worked out this was a dumb thing to say by reading “The Selfish Gene”.

Second, the author sees sacrifice as positive. Humans can create explanatory knowledge. Sacrificing yourself gets in the way of you developing better knowledge that could improve your life and the lives of others: it is a bad idea. The death of some random rabbit isn’t a big deal because the rabbit can’t create explanatory knowledge. All of the knowledge it has is instantiated in its genes. So if a copy of those genes is destroyed to preserve five copies in other animals this is a gain for the genes not a loss.

Here in the r-strategy, we see the origins of the Liberal’s tendencies towards conflict avoidance, from oppositions to free-market capitalism, to pacifism, to demands that all citizens disarm so as to avoid any chance of conflict and competition.

This is also dumb. Liberals are in favour of the government increasing taxes. They are are in favour of escalating conflict with productive people. And liberals want citizens disarmed partly to make it easy for the government to prey on them. So liberals are in favour of conflict.

Another strategy emerges if a species is in an environment where resources are very scarce. The animals are in favour of being willing to fight for resources. They are ranked by their ability to compete. And such animals will tend not to sleep around as much because they only have a limited number of chances to copy their genes and have to try to weed out bad genes in advance of having offspring. An example of this might be lions. Lions have to hunt for food. So the strategy for lion genes to get themselves copied is to rank other holders of lion genes according to their ability to hunt. And a lion may be more willing to die to preserve copies of its genes in its offspring or other relatives because dying would free up resources. This is called k selection.

The conservatives are allegedly k selected, which explains their habits like faithfulness to spouses and competing for resources instead of begging the government for stuff. This analogy also fails. Conservatives want to reduce taxes, which reduces violence used by government and the government’s ability to use violence.

Also conservatives are taking the side of makers: people who make new stuff. This position requires thinking that we have not reached the limits of what resources are available and so we can experiment with new ideas to make progress. This contradicts the premise of this r/k selection stuff. This is the most serious defect of the r\k selection theory, it denies the possibility of an open-ended stream of knowledge and resource creation. The reason to take the side of the makers is you want new and better stuff and ideas. It is not because you want to scrape by in a world where you have to murder other people to survive. This r\k selection political stuff is evil shit.

The real reason for parents to take responsibility for their children is that children can create an open-ended stream of benefits. Children and the adults they grow into can create new explanatory knowledge including knowledge about how to do stuff better. But to create knowledge people need to have good ideas about critical discussion, how to test ideas, how best to try them out and that sort of thing. To convey such ideas to their children, parents have to be willing to spend a lot of time and resources on their children rather than spending lots of time on sex. As such, responsible parents don’t spend a lot of time sleeping around. Since conservatives favour personal responsibility, they will tend to sleep around less.

All biological explanations of differences of ideas and behaviour among humans are garbage, including the r\k theory. Humans create knowledge through cultural evolution: evolution among memes. Some memes get selected, others do not. The selection time for a meme is of the order of seconds, the selection time for a gene is of the order of a decade. In addition, memes include explanatory knowledge about how stuff works and why it works that way, unlike genes. For both of those reasons, we should expect behaviour differences between people to be a result of different ideas, not different genes.

The power of inductivism

NOTE In this post, I take it for granted that inductivism is false. For criticisms of inductivism and an explanation of better ideas, see Objective Knowledge, Chapter 1 by Karl Popper, Realism and the Aim of Science Chapter I by Popper, The Fabric of Reality by David Deutsch, Chapters 3 and 7 and The Beginning of Infinity by David Deutsch, Chapters 1,2 and 4.

On an e-mail list that is now defunct, Elliot Temple asked:

What makes the idea of induction so powerful that people who normally don’t care about abstract philosophy – ones who don’t pay much attention to conjectures and refutations as the method of creativity, and certainly aren’t interested in knowing a lot about evolution – remember induction vividly, like it, bring it up on their own, and insist they do it despite it being ridiculous, extremely vague, proven not to work, and many other problems?

People like to think that science has some definite way of finding ideas and deciding which ideas are good and bad. They think of science as an authority. Science says what is true and what is false, what is good and what is bad. This is plausible if you don’t understand much and take seriously what you see on news sites, or in magazines or whatever. Science provides us with great stuff like iPhones and cancer treatments, so it must be always be right.

Inductivism is a vaguely plausible story about why science is an authority. Scientists just look at nature and nature tells them what is true. And nature proves the scientists right when they do experiments.

If science is an authority, then you don’t have to think much. There are some ideas you like. You look around for an authority to prove your ideas true. Then you can say that if somebody disagrees with you, your critic is scientifically illiterate. And you can do that not just on factual issues, but on moral issues too. For example, people for and against transsexualism like to pretend that their preference is scientific.

So inductivism is the backbone of the worldview of a lot of people. If you take it away, you’re attacking their whole understanding of the world, including all of their moral and factual knowledge. They can’t imagine any replacement.

The true theory also makes the strategies inductivists use for getting along in life look a lot worse. Science is created by guessing solutions to problems and criticising the guesses. So you shouldn’t take everything a scientist says as gospel because he’s guessing. And that means you should actually engage in critical argument rather than just insult people and pretend your insults are scientific.

The inductivist also fears that any alternative will cause a lot of conflict. Suppose that controversial moral issues can’t be solved with certainty by saying vague stuff about scientists proving something or other and claiming anyone who disagrees with you is a moron. Then people will actually have to discuss moral issues. And they think that their incompetence at discussion will lead to lots of inconclusive and long winded arguments that result in bitterness and distrust.

Such problems could be solved by trying to understand the world, and understand better moral ideas, but that takes effort most people don’t want to make. And they don’t feel confident about their ability to understand anything.

The goals misconception

In a tweet directed at David Deutsch, and some other people, a tweeter asks:

What would a decision-making agent base its decisions on if not entrenched goals?

I am going to take it that a goal means some specific fixed objective. A goal involves taking some specific kind of action. ‘Choose the best thing to do today’ is not a goal since it makes no specific claim about what you should do. ‘Go to see a film at a cinema today’ is a goal since it makes a specific claim about what you should do.

The answer to this question is that a rational person making a decision will not base his decision on anything. From a conventional point of view, this sounds ridiculous, but that conventional point of view is wrong.

Making a decision involves creating knowledge about what to do next. As such, before you can understand decision making you have to understand epistemology (the theory of knowledge) more generally. I’m not going to explain the whole of epistemology, but I will outline epistemology, explain how it is relevant and point you to where you can learn more.

Philosophers often say that knowledge is justified true belief. Justification is a process that allegedly shows an idea is good or true or something like that. People who believe in justification might hedge a bit and say it shows an idea is probably a good idea, or probably better than the alternatives. This sounds superficially like a reasonable position: who would want to act on an idea that hasn’t been shown to be true or good? The idea that you need to have a goal to make a decision assumes that it is possible and necessary to justify your decision.

The apparent reasonableness of this position is spoiled by the fact that justification is impossible and unnecessary. The correct alternative is to  focus on solving problems, not on justifying your decisions. Saying you’re going to solve problems puts you in a different position from pursuing a goal. There is no fixed standard by which you judge every decision. Rather, you look for problems with your current options and try to solve the problems. If some goal you thought was good turns out to be problematic, you can discard or modify it and you should.

Problems with justification

To understand the problems with justification, you have to understand something about how arguments work. Some arguments are informal and are not really candidates to prove anything. The fact that people are prepared to make informal arguments, and sometimes to take such arguments seriously, are problems for the idea of justification since such arguments aren’t justified. But even formal arguments don’t allow justification. Any formal argument starts with some assumptions and rules for getting conclusions from those assumptions. If the premises are true, and the rules reflect those that hold in reality, then the conclusion is true.

An example of a formal argument. If I am in the House of Commons and the House of Commons is in London, then I am in London. I am in the House of Commons, so I am in London. The rule being used is that if place A is contained in place B and object C is in place A, then it is also in place B. The assumptions are that I am in the House of Commons and the House of Commons is in London. Now, to show that the conclusion is true you have two options:

  1. Say that the rules and the assumptions are correct by fiat.
  2. Show that the assumptions and rules are correct.

Option 1 has the problem that if you admit it, then anyone can claim to prove anything by saying the assumptions are true by fiat. You can say the Earth was created 6000 years ago by saying the Bible is true by fiat. But surely we can’t just say the Bible is true by fiat because it makes ridiculous claims about some guy turning water into wine and stuff like that, but then you’ve adopted option 2. But you can see whether I’m in the House of Commons but you can’t see a lot of the stuff in the Bible because it’s abstract. There are two problems with this. First, to properly understand whether you can see me in the House of Commons you have to understand the physics of eyes and that involves abstractions. Second, the rule itself is abstraction you can’t see. So if you reject anything you can’t see you must reject the rule and the argument falls apart.

Option 2 leads to a different problem. If you’re going to show the rules and assumptions are correct you need to make another argument that justifies them. And that argument will have assumptions and rules that have to be justified. And then you have to make more arguments to justify the rules and assumptions of your new argument. And you have to keep repeating this process indefinitely, so you can never actually justify anything.

Saying that justification can make do with showing your conclusion is probably correct doesn’t solve this problem. Your conclusion is only probably correct if the assumptions and rules are probably correct, which leads to the same problem. In addition, there is no such thing as a theory that is probably correct. Your ideas are either right or wrong. And probabilities of events not of theories and can only be obtained from theories such as quantum mechanics that are themselves either right or wrong. There are other problems with assigning probabilities to theories, see The Beginning of Infinity by David Deutsch Chapter 13.

When a person thinks he has justified his ideas, in reality he has made assumptions and used rules that he has not justified. Those rules and assumptions could be wrong. Any viable epistemology has to take account of the fact that any idea you hold could be wrong. That includes ideas that you think are certainly correct. People often think an idea is obviously correct when it turns out to be flawed on closer inspection, such as the idea that justification is necessary and desirable.

The alternative to justification and goals

So if you don’t justify your ideas, including your decisions, how do you create knowledge rationally? You start with a problem. You guess solutions to the problem. You criticise the guessed solutions until only one is left and you don’t know of any criticisms despite looking for them. The surviving idea is the solution to that problem. You then move on to a new problem. This solution was first pointed out by Karl Popper, David Deutsch and Elliot Temple: it’s called critical rationalism.

For more details on critical rationalism, see Objective Knowledge Chapter 1 by Popper, Realism and the Aim of Science Chapter I by Popper, ‘one the sources of knowledge and of ignorance’ inConjectures and Refutations by Popper, chapters 3 and 7 of The Fabric of Reality by David Deutsch, most of The Beginning of Infinity by David Deutsch and Critical preferences and strong arguments by Elliot Temple.

So how do you apply this to making decisions? Your decision making has to start with a problem you’re trying to solve. You might be trying to decide what to have for breakfast. You then look for solutions to the problem. You could have cereal, or boiled eggs or whatever. Then you look for problems with the options. You might not have enough time to make and eat boiled eggs, so you pick cereal. So then you’ve solved the problem by picking cereal.

But your breakfast decision could go very differently. You might find that when you wake up you’re not hungry. So then you might think eating is pointless and you decide not to have breakfast at all. So you had a goal when you started the problem: the goal of having breakfast. And you ditched that goal because you had a criticism of it. If you had looked on having breakfast as a goal you must fulfil, you would have missed the option of not eating breakfast. So thinking of decision making in terms of goals is an obstacle to making rational decisions.

The misconception that you need to have goals is one of many misconceptions that can get in the way of making rational decisions. And you can’t expect to get rid of all your misconceptions without rational discussion, so you may want to read Fallible Ideas and contribute to the e-mail list linked on that page.

Paying for water

A tweeter asks David Deutsch about paying for water:

@DavidDeutschOxf Random Q: Us paying for water on a planet that is two-thirds water is, at this point, a lack of creativity or knowledge?

Some replies pointed out that you’re paying to have water without toxic stuff in it, or in convenient forms like bottled water. But the system of paying for water itself is an example of creativity and knowledge at work.

There are lots of choices about how to make and distribute water for drinking and other purposes.

Suppose that the only water around was salty. To get drinkable water you would have to remove the salt. This is often done by distilling the water. You make the water evaporate collect the evaporated water and condense it so that it turns back to liquid. But there are lots of possible ways of distilling water.

In some places, such as the UK lots of non-salty water falls out of the sky. So there is non-salty water around for people to use. But the UK could produce more drinking water by desalination.

And when people use water they often render it undrinkable and useless for other purposes, e.g. – they pee in water that is in a toilet. So if you want to use the water again it has to be treated.

And for some applications of water, you want water that is prepared in a more complicated way than drinking water. In chemistry experiments, people often want very pure water with no additives. But tap water often has chemicals in it, e.g. – fluorides. So tap water is no good for some chemistry experiments.

And water can be delivered to the consumer in lots of ways. You can get it in bottles or out of a tap. Or you can take tap water and put it into a machine that purifies the water.

So how do you make a choice among all those options? And how do people decide what delivery options to offer, what purity of water to offer and so on? Pricing is a way of helping people make such decisions.

You can exchange money for a very wide variety of goods. Anything that people are willing to offer in trade can be traded for money in most circumstances in advanced industrial societies. Money is a medium of exchange: it is a good you acquire so you can use it to acquire other goods. This means that you can deal with anyone who has a good you want. If there was no medium of exchange you would have to have some specific good on hand that your trading partner wanted. Without money, if Bob wants milk and Jim wants a chicken but all Bob has is corn, Bob would have to go trade the corn for a chicken before he could get the milk. Instead of doing this, Bob can just give Jim money and Jim can buy his own chicken. Money is a creative solution to the problem that it is difficult to arrange for the wants of trading partners to coincide without a medium of exchange.

If you’re choosing among different ways of getting water you can look at the cost of the different options to decide among them. If you’re running a chemistry experiment, you might decide that having pure water is worth the cost of buying  device for purifying tap water. You prefer the water purifier to the other stuff you could buy with the money you allocate to buying the purifier. If you’re just making tea, you might decide the water purifier isn’t worth the cost: you prefer the other stuff you could buy with the money to the water purifier. If you’re going out cycling you might be willing to pay for bottled water so you can have it in a convenient container. But you might not pay for bottled water if you are at home.

And if people are trying to choose among different ways of supplying water, they can look at whether people are willing to pay enough to make it worthwhile. If non-salty water falls out of the sky in the UK it might not be a good idea to build a desalination plant here. People aren’t willing to pay enough, they prefer the other goods they can buy with the same money. In other places, rain water doesn’t provide what people need for drinking, farming and so on. So people will pay for desalination because they prefer more water to the other stuff they could get with that money.

Some books you could read to understand more about economics include Economics in one lesson or Time will run back both by Henry Hazlitt. For a much longer and deeper explanation see Capitalism by George Reisman.

Why should you learn physics?

In a comment, Elliot Temple asked questions about when and why people should learn physics:

what’s the point of learning about physics? who should learn about it and why? should everyone learn about physics? how should someone decide if they should learn some physics, and which physics, and how to learn it?

There are several reasons people might want to learn about physics.

(1) Learning physics involves figuring out stuff, which can be fun. It’s like trying to figure out a very complicated puzzle. One difference from trying to solve a puzzle invented by a person is that  for lots of physics problems nobody knows the answer. There are some puzzles invented by people for which nobody knows the answer. You can have computer games in which a program generates a puzzle. But even in cases like that the rules for generating the puzzle are known and written down in the text of the program. The laws of physics are not known or written down in many cases.

(2) You can want to learn physics for technological reasons. The laws of physics rule out some ways of solving problems. For example, you can’t travel faster than light so technology that requires faster than light travel won’t work.

(3) You can want to learn some physics for philosophical reasons. There are philosophical disputes about stuff like whether it is possible to understand the world and physics is relevant to those disputes. A person is a physical object, so a person can’t know X if learning X requires breaking the laws of physics. In The Beginning of Infinity, David Deutsch argues that all problems that are worth solving can be solved. This rules out some bad ideas people have about people being unable to understand how the world works cuz our brains evolved by natural selection only to solve some problems, see BoI Chapter 3 starting at about p. 53.

You can comment on the above or explain reasons I left out in the comments below.