Sunday, January 24, 2010


Realism or Antirealism

A thought:

If we accept the idea that science really does give us some sort of knowledge then we must examine what scientific theories tell us about how the world is, and decide what is the scope of scientific knowledge. The modern scientific picture of the world seems to tell us a great deal, not just about how things are now, but how they were millions and even billions of years ago. Astrophysics tells us about the formation of the Earth, the solar system and even the universe, geophysics tells us about the development of mountains, continents and oceans, and biochemistry and evolutionary biology tell us about the development of life itself. Such scientific theories tell us more about familiar things, so, for example, we may learn where a particular river used to flow or how bees pollinate flowers. However, scientific theories, especially those in physics and chemistry, also describe entities that are not part of our everyday experience, such as molecules, atoms, electromagnetic waves, black holes, and so on. Such theories raise particular problems and questions in the philosophy of science; for example, should we believe in the existence of such esoteric and unobservable entities, and if so, what is to count as evidence for their existence and how do we manage to refer to them?

Of course, science does not just describe the world; it also gives us explanations of how and why things are as they are. Often this involves describing unobservable causes of things we observe. Hence, Newton is not famous for discovering that unsupported objects fall to the Earth, he is famous for explaining why they do so (the gravitational force is what causes apples to fall out of trees), and for giving us a law that allows us to calculate the rate at which they do so. Newton's mechanics, like many scientific theories, is formulated in terms of a few fundamental principles or laws. Central to our understanding of science is this idea of laws of nature; for example, it is supposed to be a law of nature that all metals expand when heated. So science seems to tell us about the ultimate nature of things, what the world is made of and how it works. It has even been thought that science has replaced metaphysics not just by telling us about what exists, and explaining what happens in terms of laws of nature and causation, but also by answering other fundamental philosophical questions about, say, the nature of space and time. But what exactly is a law of nature, and what does it mean to say that something has caused something else? What is it to explain something?

Many philosophers and scientists take it for granted that the aim of science is not merely to describe what we see, but also to arrive at the truth about the unobservable entities, laws and causes that lie behind the phenomena we observe. On the other hand, there is also a long tradition of disregarding questions about the real nature of things, the laws of nature and so on, and emphasising instead the search for theories that accurately predict what can be observed, without worrying about whether they are true or false beyond that. The question ... is, 'ought we to believe in the unobservable entities postulated by our best scientific theories?', or more crudely, 'do electrons really exist?'.

- James Ladyman, Understanding the Philosophy of Science

'do electrons really exist?'

I vote yes (though I've never seen one), but their existence (plus or minus, if you will) isn't likely to affect the patterns of distribution of genetic variability in a population of gynodioecious bladder campions (as an example). Most science is done in a context of multiple black boxes ("someone else is dealing with this bit"). Couldn't possibly work otherwise.
Most science is done in a context of multiple black boxes ("someone else is dealing with this bit"). Couldn't possibly work otherwise.

Quite true. But someone should think about it ... which is why god invented philosophers.
Unobservable atoms? is a picture of some.

Black holes are as unobservable as Newton' gravity. We can't see them directly but sure can see there effects.

Speaking of Newton and gravity, no he did not explain *why* objects fall to the Earth. He just described how the force of gravity (and forces in general) work.

And laws of nature are not fundamental principles on how the universe works. They tend to be very specific descriptions of very small pieces of the universe, frequently in an idealize scenario.

And yes, science *is* limited to finding accurate descriptions of the observable. Just as a carpenter does not worry if his hammer is true or not, only if it works for driving a nail, a scientist only cares if a theory makes accurate predictions, not whether it is The Truth.

But hey, he's the professional. His understanding of science is probably better than mine.
Ah, but how do we know our instruments are showing us an accurate picture of atoms? That was actually an objection to Galileo's use of the telescope to observe Venus but, in his case, he could show it was accurate in our own macro world. The more divorced the instruments become from our macro world, the tougher the problem becomes. And of course, atoms are great hulking things when compared to electrons.

As for black holes, when we see the "effects" of them, that means there is theory involved (we see "effects" of black holes only to the extent we have a theory as to what black hols should do).

Surely a "skeptic" won't accept a scientist's explanation of how science should be done on his/her word alone.
[Realizing that you are playing devil's advocate somewhat...]

That shot of atoms was done with an electron microscope, which also can take pictures of items on the macro scale. (For example this picture of an ant: So the parallel to Galileo's telescope is quite close.

Black holes...gravity, both the same black box mystery. I don't *see* anything pushing objects to Earth. But for some reason, Ladyman makes a distinction betweet these two phenomena (actually, two effects of the same phenomenon.)

This whole "truth" business is just a shroud for some nihilism and scientists are wise to avoid it. They know their theories and models are not The Truth. We know that Newton's Laws of Motion are wrong but we still teach it in science class because it works (mostly.) If we were worried about truth, we wouldn't teach it and a useful tool would be lost.
So the parallel to Galileo's telescope is quite close.

Yes, I know. But that doesn't help with electrons.

This whole "truth" business is just a shroud for some nihilism and scientists are wise to avoid it. They know their theories and models are not The Truth.

Really? I've seen some pretty strong statements about science delivering "truth" ... particularly when the subject is metaphysics.

Ladyman is just prefacing his discussion of scientific realism vs. antirealism, which is an area of real dispute.
From your link: "According to scientific realists, for example, if you obtain a good contemporary chemistry textbook you will have good reason to believe (because the scientists whose work the book reports had good scientific evidence for) the (approximate) truth of the claims it contains about the existence and properties of atoms, molecules, sub-atomic particles, energy levels, reaction mechanisms, etc. "

Now, is that for a book published before or after a Texas education committee gets done with it?
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