Theory and practice: what to blame?

[daniel]

It is often said that if something is bad in practice than it can't be good in theory. However what do you think of this view: it's not the theory that's to blame but the world, the people etc. The ideas are still right it's just this world that lets them down and so we can't criticse the theory.

[DavidOdden]

I think that if it's bad in practice then it's bad in theory, but what's bad may not be the basic idea, rather it's the particular claim. For example, educating everybody so that they are highly intelligent and well informed at a doctoral-research level about everything is good. But just try to do it: the actual implementation has been a disaster. Why? First, because most people don't actually want it. Second, because most people aren't capable of that level of education (like, my math skills suck). Third because it's a terribly expensive proposition payed for with tax money. Fourth, because incompetent and unqualified people often end up teaching it. Fifth, because capable and incapable students are shoved into the same mixing bowl.

Suppose you were asked "Do you think it would be good to force everybody to be universally educated to the highest levels, regardless of their interests, capabilities or willingness, with no attempt to group people together by ability, to be taught by people who may be totally clueless and to be taught a curriculum by a committee that is totally clueless?". Is that good in theory? I don't think so.

Freedom is good, and it would be good to not have to have police of a military. Absolute freedom (anarchy) is bad; but it is good to have the freedom to act on your own judgment to advance your life, as long as you respect the rights of others. Anything that is "good in theory, bad in practice" is bad because some context was dropped.

[Galileo Blogs]

Do you have some examples of such a theory as you describe where:

The ideas are still right it's just this world that lets them down and so we can't criticse the theory.

[D'kian]

The ideas are still right it's just this world that lets them down and so we can't criticse the theory.

Well, a theory that doesn't take into account the known facts of this world, is a bad theory and will not work in practice. Contradictions cannot exist.

Here's an idea: it would be cheaper to run a car on water than on gas. Surely it would. Water is plentiful and readily available. But water does not burn, that is it can't be made to release energy that an engine can use. If you ignore this fact, you can go on and design a car that will run in theory but be immovable in practice. Then would it be fair to say the theory was good and shouldn't be criticized?

[necrovore]

It is often said that if something is bad in practice than it can't be good in theory. However what do you think of this view: it's not the theory that's to blame but the world, the people etc. The ideas are still right it's just this world that lets them down and so we can't criticise the theory.

In order to answer this question you must draw a distinction between the natural and the man-made.

A theory has to take the natural world into account; a theory that fails to do so is a bad theory. Many examples have already been pointed out on this thread.

For someone to say, well, the theory is correct but the natural world has let it down, is just ludicrous. The natural world is what it is and has to be accepted as such. It is silly to blame the natural world for not conforming to one's fantasies.

However, a theory that is intended to conform to the world cannot take into account what people think. The opinions of people -- regardless of their numbers -- should not take precedence over reality. Just as an individual can be wrong, a society can be wrong.

And so it is possible for society to let down a theory. We saw it with Galileo, and we see it today with scientists who dare to dispute global warming.

Freedom is the antidote to this. If a person is free to spread his theory and to demonstrate it, it will eventually win out because of its conformance to reality.

[Galileo Blogs]

Well, a theory that doesn't take into account the known facts of this world, is a bad theory and will not work in practice. Contradictions cannot exist.

Here's an idea: it would be cheaper to run a car on water than on gas. Surely it would. Water is plentiful and readily available. But water does not burn, that is it can't be made to release energy that an engine can use. If you ignore this fact, you can go on and design a car that will run in theory but be immovable in practice. Then would it be fair to say the theory was good and shouldn't be criticized?

Your example contradicts your own standard. The theory of your water car fails to "take into account the known facts of this world," specifically, the fact that water does not burn. Therefore, the theory that cars could run on water is a flawed theory.

A theory could take into account the facts of reality and still be a bad theory, because it does not take into account all of the relevant facts of reality. Or, the facts may be improperly construed. Or, as in your example, it could assume something as a fact which isn't.

One of my favorite examples of a flawed theory leading to disastrous results in reality is from economics. It is the theory of perfect competition. The theory supposedly describes how markets work, but it does so by assuming away some very important features of the market. In particular, it assumes that knowledge is costlessly and instantly acquired by all market participants. With this false view of reality as its base, the theory projects that no market participants would have "market power" because all information about all processes and all prices are instantly and simultaneously known to everyone in the economy. Of course, that is not true. Information is costly. Innovations in technology and business practices are costly to acquire. Because information is costly, everyone has "market power," i.e., they have the ability to influence the price and quantity at which they sell their product, whether it is their own labor, or something they are making and selling.

Even though the theory of perfect competition is a demonstrably bad theory because it makes false assumptions about reality, it serves as the intellectual justification for a host of destructive economic policies. The worst of these is antitrust, which attempts to force companies to behave in a "perfectly competitive" manner. In practice, all these laws end up doing is thwarting the accumulation of capital, blocking economically efficient mergers, outlawing many forms of competition involving quality instead of price, and generally punishing business success. The theory behind antitrust, perfect competition, is imperfect itself. Therefore, when attempting to develop policies based on that theory, those policies are destructive/impractical.

However, the theory of perfect competition and antitrust is a long topic for another thread, if it hasn't been discussed already.

There should be no gulf between theory and practice. A true theory is practical. A false theory is impractical.

*****

I can't help giving one more example. Imagine a rocket engineer who develops a grand theory for a new rocket. Everything is perfect, except he assumes away one messy fact of reality: air friction. His equations "work" better by assuming no air friction (just like the economists' equations "work" better by assuming away the messy fact that information is costly). Everything looks good on paper. However, when it comes to the day he launches his rocket, it only goes up so far in the atmosphere before running out of fuel and crashing back down to earth. It fails to reach orbit because there wasn't enough fuel in the rocket to overcome the drag from air friction as it passed through the atmosphere.

That was a bad theory, with bad consequences.

[DavidOdden]

A theory could take into account the facts of reality and still be a bad theory, because it does not take into account all of the relevant facts of reality. Or, the facts may be improperly construed. Or, as in your example, it could assume something as a fact which isn't.

I'm confused about this part. On the first count, I do understand how a person might think that the meaning of "the facts of reality" allows the interpretation "some of the facts of reality, but not all of the facts of reality", but usually, when you say "the facts", you mean "all of the facts". An "all" would make that clearer, though more verbose. At any rate, bare plurals like "the facts" conventionally mean "all", in this type of context. I don't know how you can take the facts into account and yet improperly construe them, unless you mean "take some facts into account, and create other unsupported conclusions based on invalid logic applied to those facts". I would say that this isn't taking the facts into account, it's making stuff up. And of course if something isn't so, then it's not a fact, so "taking the facts into consideration" implies that they are real, not unreal (but, "taking all opinions into consideration" doesn't mean that the claims are facts).

Now I am also positive that some people are willing to claim to have taken the facts into account, and yet do as you described; but then I would not say that they have taken the facts into account, just that they have deluded themselves into thinking that they have.

[Galileo Blogs]

usually, when you say "the facts", you mean "all of the facts".

I agree with your objection. I should have said, "A theory could take into account some of the facts of reality and still be a bad theory, because it does not take into account all of the facts of reality."

I agree with you also that when someone says, "the facts" in the above context, it does imply "all of the facts."

Of course, I still love it when the bailiff swears in a witness on Perry Mason and asks, "Do you swear to tell the truth, the whole truth, and nothing but the truth?" It just doesn't sound as dramatic to say, "Do you swear to tell the truth?"

Edited January 28, 2007 by Galileo Blogs

[DavidOdden]

It just doesn't sound as dramatic to say, "Do you swear to tell the truth?"

Imagine the legal chaos if they said "Do you swear to tell truths?".

[D'kian]

Your example contradicts your own standard. The theory of your water car fails to "take into account the known facts of this world," specifically, the fact that water does not burn. Therefore, the theory that cars could run on water is a flawed theory.

Right. That's why I said you have to ignore water's inability to provide energy.

A theory could take into account the facts of reality and still be a bad theory, because it does not take into account all of the relevant facts of reality. Or, the facts may be improperly construed. Or, as in your example, it could assume something as a fact which isn't.

A fact, often a key fact, may be unknown at the time, too. For a good example, look up the search for a planet named Vulcan, which never existed. Given what was known at the time, it made perfect sense to postulate the existence of an intra-Mercurial planet. It even made sense it would be hard to spot (Mercury is hard to spot).

But that's an honest mistake, based on an incomplete understanding of natural law. The key fact missing, which XIX century science had not discovered yet, was the equivalence of matter and energy. Had astronomers known of it at the time, they'd have known what perturbed Mercury's orbit, and they wouldn't have gone chasing after a phantom planet.

Just the same, the Vulcan theory to explain Mercury's peculiarities was a bad theory, even if it was the best science could come up with at the time.