Category Archives: Philosophy

The Uncertainty Principle and Us

Posted on by

It’s difficult to discuss physics if you aren’t a physicist or don’t understand the math involved. Nevertheless, what physicists tell us about the world is so strange that it’s hard not to discuss it sometimes, whether we understand it or not. (The brilliant physicist and all-around cool guy Richard Feynman once said that nobody understands quantum mechanics, but some understand it better than others.)

There are philosophers who specialize in the philosophy of physics and aren’t shy about discussing physics at all, among themselves and with physicists. One of these philosophers, Craig Callender, has recently written two interesting articles for the New York Times. In these articles, Callender argues that Werner Heisenberg’s uncertainty principle, probably the best-known part of quantum mechanics, shouldn’t be as famous as it is. 

Heisenberg was one of the founders of quantum mechanics. He published the uncertainty principle in 1927. If you look up “uncertainty principle” now, you’ll find statements like this: “The position and momentum of a particle cannot be simultaneously measured with arbitrarily high precision” and “The uncertainty principle is at the foundation of quantum mechanics: you can measure a particle’s position or its velocity, but not both.”

Well, here is Callender on quantum mechanics:

[Quantum mechanics is] a complex theory, but its basic structure is simple. It represents physical systems – particles, cats, planets – with abstract quantum states. These quantum states provide the chances for various things happening. Think of quantum mechanics as an oddsmaker. You consult the theory, and it provides the odds of something definite happening….

The quantum oddsmaker can answer … questions for every conceivable property of the system. Sometimes it really narrows down what might happen: for instance, “There is a 100 percent chance the particle is located here, and zero percent chance elsewhere.” Other times it spreads out its chances to varying degrees: “There is a 1 percent chance the particle is located here, a 2 percent change it is located there, a 1 percent chance over there and so on.”

According to Callender:

The uncertainty principle simply says that for some pairs of questions to the oddsmaker, the answers may be interrelated. Famously, the answer to the question of a particle’s position is constrained by the answer to the question of its velocity, and vice versa. In particular, if we have a huge ensemble of systems each prepared in the same quantum state, the more the position is narrowed down, the less the velocity is, and vice versa. In other words, the oddsmaker is stingy: it won’t give us good odds on both position and velocity at once.

Callender then points out that he hasn’t said anything about measurement or observation:

The principle is about quantum states and what odds follow from these states. To add the notion of measurement is to import extra content. And as the great physicist John S. Bell has said, formulations of quantum mechanics invoking measurement as basic are “unprofessionally vague and ambiguous.” After all, why is a concept as fuzzy as measurement part of a fundamental theory?

Callender later shares another quote from J. S. Bell (considered by some to be the greatest physicist of the second half of the 20th century):

What exactly qualifies some physical systems to play the role of “measurer”? Was the wavefunction [the quantum state] of the world waiting to jump for thousands of millions of years until a single-celled living creature appeared? Or did it have to wait a little longer, for some better qualified system … with a Ph.D.? If the theory is to apply to anything but highly idealized laboratory operations, are we not obliged to admit that more or less “measurement-like” processes are going on more or less all the time, more or less everywhere?

When physicists use their instruments to measure a subatomic particle’s position or momentum, the instruments affect the particle. It’s the interaction at the subatomic level between the instrument and the particle that’s important, not the fact that the interaction has something to do with measurement, observation, mental energy or human consciousness. We aren’t that important in the vast scheme of things.

Viewing the theory of quantum mechanics as a cosmic oddsmaker may seem unhelpful. We want to know what’s going on at the subatomic level that results in the theory calculating certain odds. Heisenberg thought physicists shouldn’t even think about an underlying reality — they should simply focus on the results of their observations. But some (many?) physicists working today believe that quantum mechanics is an incomplete theory that will eventually be replaced by a more fundamental theory, possibly one that explains away the apparent randomness that exists at the subatomic level (that’s what Einstein thought too). Their hope is that uncertainty will one day be replaced by certainty, or something closer to it.

If you do a Google search for “uncertainty principle consciousness”, you’ll probably get more than 8 million results. If you search for “uncertainty principle measurement”, you can get more than 32 million. Professor Callender thinks those numbers should be much, much smaller.

——————————————————————————————————————– 

This is Callender’s first article in the Times:

http://opinionator.blogs.nytimes.com/2013/07/21/nothing-to-see-here-demoting-the-uncertainty-principle/

Here he responds to questions and criticisms from readers:

http://opinionator.blogs.nytimes.com/2013/07/25/return-of-the-stingy-oddsmaker-a-response/

What It Means to Really Believe

Posted on by

At some point along the way, most philosophers came to the conclusion that having a belief isn’t simply an internal state of the believer. One might suppose otherwise — that in order for Mary to believe some proposition P, she simply needs to be in the appropriate internal mental state, perhaps one in which she is silently saying to herself “You know, I really believe P”.

There is some truth to the internalist view. After all, we sometimes reach conclusions without announcing them to the world. Archimedes could have stepped into his bathtub, noticed how the water rose and immediately acquired a belief about how to measure the volume of irregularly-shaped objects — while keeping his mouth firmly shut, saving “Eureka!” for another time and place.

One problem with this view, however, is that it seems wrong to say that Mary believes P if her behavior is (consistently) inconsistent with believing P. Say, for example, that Mary claims to believe that all Americans should pay their required income tax, yet fails to pay any tax at all on her extremely high income. When the IRS comes calling, she is nowhere to be found. Mary might loudly proclaim that she believes in paying her income tax — she often says to herself “We Americans should all pay what we owe to the IRS” — but we would be remiss if we didn’t reply: “You claim to believe that, Mary, but your behavior shows that you really don’t”.

I was recently moved to think about what it means to really believe by an exchange of views on an Internet message board. The subject of this particular board is a certain fairly well-known musician. During a recent discussion, a Christian gentleman, veering seriously off-topic, wrote the following:

I got on here before and some people complained, saying that I shouldn’t be using the forum for a place to discuss God. It started a controversy. The people here who go to church etc, and those who don’t. It starts a conflict. That’s the way witnessing is. That’s the way it always is. I won’t continually use the forum here to witness day to day, etc. That’s not the only purpose of the community here. People have a right to get on here and talk about music without someone telling them that they need God. I understand that. But I can’t deny God when I need to mention Him.

And later:

We don’t have to be preaching every minute of the day…. I am getting ready to take a trip up the road to the place I go to see flowers, etc. I don’t feel that I am lost because of it. There is plenty of time for me to enjoy my life, whether it is music, art or whatever, being with family, etc.

The question that occurred to me was: how should a person behave if he really, truly believes that the Christian God exists and that each of us is going to face an eternity of paradise or damnation? How much time should a person spend “witnessing”, i.e. doing God’s work by trying to convince other people of the truth of Christianity, so that they might enjoy a good afterlife? Should one witness only when the mood strikes? An hour a week? One day a week? Five days a week? Every waking hour?

Charles Stanley, of the First Baptist Church in Atlanta, put it this way: “God’s plan for enlarging His kingdom is so simple — one person telling another about the Savior. Yet we’re busy and full of excuses. Just remember, someone’s eternal destiny is at stake.”

Here’s another example. If you truly believe that every fertilized egg is a full-fledged human being, so that abortion is murder plain and simple, what should you do to stop abortions? If you really believe that there are murders being committed every day in a neighborhood clinic, is it enough to express disapproval to your friends, or to show up once a week outside the clinic and try to convince women not to go inside? Or should you be doing something much more dramatic? If you believed that children were being murdered every day in the back room of your local 7-11, what would you do to stop it from happening?

I go back and forth between atheism and agnosticism (do I believe that God doesn’t exist? Or do I strongly doubt it?). So I’m asking these questions as an outsider. I’m not trying to live according to the supposed dictates of the divine ruler of all creation. But I wonder why more Christians don’t behave like those Asian monks, giving up their worldly pursuits, leaving their loved ones and spending all of their time preaching and praying, relying on donations to survive (remember that comment about rich people finding it terribly difficult to get into heaven).

Do serious Christians truly believe what they claim to believe? I think the answer is “yes”, but why don’t they behave more often as if they do?

One answer is that they think some level of prescribed behavior is “good enough”. It isn’t necessary to be a perfect Christian. You just need to meet some minimum requirements in order to get to heaven, so why do more? It’s only right that we should enjoy life while we can, even if that means a few more souls end up in Hell and some more babies are murdered. 

Another possibility is that the seriously religious don’t feel it’s necessary to be their brother’s keeper. So long as they (and their loved ones, perhaps) are doing the right thing, they don’t have a responsibility to make sure that everyone else does the right thing too. It would be wonderful if lots of other people could be saved and go to heaven. It would be wonderful if there were no more abortions. In fact, it’s your Christian duty to do what you can to make those wonderful things happen, but only within reason. It isn’t necessary to devote your whole life to other people’s problems. 

Or maybe they just haven’t thought too hard about this kind of thing. They grew up in the church, saw how other Christians behaved and followed their lead. That’s human nature. 

P.S. — I could have written about Islam instead of Christianity, of course. It’s doubtful that all Muslims try to be perfect Muslims. Unfortunately, a tiny minority of Muslims take their religion extremely seriously, mixing it with politics to violent effect.

Hope I Die Before I Get Old

Posted on by

Well, so much for that plan.

Definitely still alive, I’ve spent the past 2 weeks reaping the benefits of modern medicine. The problem that put me in the hospital and the medical treatment I’ve received have added up to something approaching “advanced interrogation techniques” (I’ll tell you anything — make it stop!).  

I did have a lot of time to think, however, while lying in bed waiting for something good to happen. I reached some small conclusions and a big one.

One of my small conclusions:

A doctor who is “on call”, responsible for off-hours phone calls from patients, shouldn’t be unavailable for hours at a time. But if an “on call” doctor can’t take calls for some reason, there should be another doctor who serves as the first doctor’s backup. Then, after repeated failures to reach Doctor 1, the answering service can contact Doctor 2 instead.

Another small conclusion (with apologies to the nursing community and anyone offended by discussion of bodily fluids):

If you have fluid draining into a plastic bag, and the bag becomes rather heavy as it fills up, in such a way that the drainage mechanism may no longer function properly, reject your nurse’s advice to empty the bag “when it fills up”. Instead, empty the bag “before it fills up”.

And my big conclusion, with a little background first:

Some people are extremely careful about diet and exercise. Others eat whatever they want and avoid exercise whenever possible. Most of us occupy some middle ground. Personally, I eat too much food that isn’t good for me and don’t exercise very often. I’ve never seen the point of doing otherwise, since I’ve never been very concerned with the state of my body and never wanted to live an extraordinarily long time. I’ve been content to drift along, eating what tastes good and avoiding perspiration if possible.

Having been hospitalized twice in the past 12 months for kidney-related problems, however, I now understand that I’ve been missing something important about diet and exercise. I’ve always thought the point of eating well and working out was to achieve a positive, healthy state — to be one of those happy, early to bed, early to rise types who can be so annoying to the rest of us. But that’s not the point at all.

The point of eating well and working out is to avoid the incredible pain and discomfort of serious illness and the medical treatment that goes with it. It isn’t a matter of getting something good; it’s a matter of avoiding something bad.

You might say that, in this case anyway, getting something good and avoiding something bad are just two sides of the same health-related coin. You can’t have one without the other. There is certainly some truth to that, since there’s a single path leading to both goals. But in terms of motivation, there is a big difference between trying to achieve something really good and trying to avoid something really bad. In my case anyway, I’ve never been interested in achieving a wonderfully healthy state. Mediocrity has been fine with me. 

Having experienced the extremely unpleasant downside of a poor diet (and, to a lesser extent, limited exercise), I find it much more motivating to try to avoid this kind of downside in the future, if I possibly can, than to seek something positive. At this point, if I have any sense at all, I’m going to eat better and exercise more. Of course, there’s no guarantee that changing my habits will insure that I won’t have to go through this kind of crap again. We all know that life isn’t that predictable. On the other hand, if you want to avoid something really bad, you should do what you can, if the cost of doing so isn’t that great. That’s just being rational.

Hence, my big conclusion:

Not being motivated by the prospect of getting something good, I’m going to focus instead on what I’m desperate to avoid. Avoiding pain can sometimes be a much better motivator than achieving pleasure. If I don’t want to be tortured again, I need to try something different. 

Philosophical addendum:

It occurred to me while writing this that philosophers (Western philosophers anyway) have tended to discuss the pursuit of pleasure more often than the avoidance of pain. As you might expect, the Stanford Encyclopedia of Philosophy has an article called “Happiness”, but none called “Unhappiness”. The article on happiness contains 397 uses of the word “happiness” and 6 uses of “unhappiness”. 

To be fair, however, Jeremy Bentham defined “happiness” as the predominance of pleasure over pain. He argued that: 

Nature has placed mankind under the governance of two sovereign masters, pain and pleasure. It is for them alone to point out what we ought to do, as well as to determine what we shall do. On the one hand the standard of right and wrong, on the other the chain of causes and effects, are fastened to their throne. They govern us in all we do, in all we say, in all we think … 

Yet how can one serve two sovereign masters? Do pleasure and pain somehow work together, like the two ends of a seesaw, always giving coherent direction (“You, boy, go up now!”)? I don’t think so. Pain isn’t merely the opposite of pleasure. It’s its own phenomenon and deserves at least equal consideration, maybe more consideration, than pleasure gets. But we have a cultural prejudice that says it’s better to search for the good things in life than to avoid the bad. That isn’t always the case.

From the Cicada’s Perspective (Again With the Cicadas!)

Posted on by

Having a perspective is one of the things that generally sets us apart from inanimate objects (putting aside some inanimate objects like radio telescopes). A cicada has a perspective too, although it’s presumably not quite as nuanced as ours.

From our perspective, it can seem rather sad that these living things are stuck underground for 17 years, only to spend a few days or a few weeks in the open air before dying. It doesn’t seem like much of a life.

On the other hand, if we were to go very far out on a limb and attribute emotions and conscious reflection to these little creatures, we might suppose that they are perfectly happy living underground, away from birds and car tires, resting comfortably in the dark, taking sustenance from tree roots.

The years go by and one day they have to leave their homes, exposing themselves to all kinds of strange goings on, climbing trees, going through metamorphosis, flying around, making so much noise looking for a mate. What a pain! Can’t I stay down here for another decade or so?

Or maybe they feel suddenly liberated? Having been imprisoned in the earth, serving what amounts to a life sentence, they finally get to leave their jails, have some fun if they’re lucky and then call it a day. What a relief! I’m glad that’s over. I’ve done my bit and now it’s time to shuffle off this mortal coil.

Those Crazy, Mixed Up Photons

Posted on by

On the website of the American Association for the Advancement of Science, a physicist recently wrote:

Suppose you have a quantum particle of light, or photon. It can be polarized so that it wriggles either vertically or horizontally. The quantum realm is … hazed over with unavoidable uncertainty, and thanks to such quantum uncertainty, a photon can … be polarized vertically and horizontally at the same time. If you then measure the photon, however, you will find it either horizontally polarized or vertically polarized, as the two-ways-at-once state randomly ‘collapses’ one way or the other.

This two-ways-at-once state is called “superposition”. The idea is that something can be in more than one state (or “position”) at one time, i.e. a super-position.

However, saying that a photon can be polarized vertically and horizontally at the same time, or that it can be in a “two-ways-at-once” state, looks extremely suspicious. It’s hard to know what such a statement means, if anything. After all, language is based on logic (it wouldn’t work otherwise) and logic is based on the law of contradiction: proposition P cannot be both true and false, assuming that P has a single, precise meaning.

The proposition that photon p is polarized vertically at time t has a single, precise meaning. So does the proposition that photon p is polarized horizontally at time t. Yet these statements certainly look contradictory. It looks as if we have to give up the law of contradiction in order to accept them both.

To avoid the contradiction, however, it might be preferable to say that a photon can be in an indeterminate state, in which its polarization is neither vertical nor horizontal. It’s potentially in either state, but it’s not in either one until its state is measured (or otherwise affected), at which point the photon randomly ends up in one state or the other.

Viewed in probabilistic terms, the fate of Schrödinger’s cat doesn’t seem to be a problem (to me anyway). It was alive when it was put in the box and presumably remained alive unless it was poisoned as the result of a random sub-atomic event. We don’t have to say that the cat is now both dead and alive (or in some twilight state). It’s just a cat that may have died and there is a certain probability that it did.

But then there is the famous double-split experiment. This experiment shows that photons don’t behave like cats (or dogs) or, in the philosopher J. L. Austin’s phrase, “medium-sized dry goods”. A single photon travels through two slits and creates a wave-pattern on the other side, even though common sense tells us that the photon can only travel through one slit or the other. The bizarre but reasonable conclusion is that the photon actually takes every possible path through the two openings, not just in theory, but in fact.

Fortunately, there isn’t any contradiction in saying that the photon goes through slit 1 and slit 2 at the same time, since saying that it goes through slit 2 doesn’t conflict with saying that it also goes through slit 1. In similar fashion, photons can be polarized horizontally and vertically at the same time, because that’s the kind of thing that can happen to the crazy little bastards (i.e. sub-atomic particles).

We are used to saying things like “a person can’t be in two places at the same time” (many episodes of Law and Order are based on that premise). Logic tells us that if the number 5 is odd, it can’t be even. Logic and experience tell us that if Miss Scarlet was in the billiard room, she wasn’t in the conservatory. That’s how numbers and people work. Photons don’t work that way. It’s extremely strange, but not incomprehensible and not contradictory.

http://news.sciencemag.org/sciencenow/2013/05/physicists-create-quantum-link-b.html