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I agree entirely with the OP, but I have also seen people treating computation as a "third leg", to the detriment of progress I think. Let me concoct a trivial
by frossie 16y ago
I agree entirely with the OP, but I have also seen people treating computation as a "third leg", to the detriment of progress I think.
Let me concoct a trivial example. Suppose you wanted to know whether a bowling ball would drop from the top of a building faster than a tennis ball. You can do this without reference to theory - just go out and experiment. Doing the experiment would not give you the complete physical picture perhaps, but it would certainly
(a) answer your narrow question and
(b) give you a constraint that any theory must explain.
The problem is that there is a class of research where people who are faced with this question, would set up a computer model. Now let's say they didn't realise they had to model air resistance. They will discover something all right, but it will neither answer the narrow question, nor provide a robust constraint for theory.
In other words, playing around with computational models is not, by itself, theory or experimentation unless you are very careful on how you tie it back to the physical world.
- krupan 16y agoI agree that this was a great little essay. I like your illustration, but I think your point at the end of your comment disagrees a little with the essay, and I have to disagree with you a little as well. A computational model, such as Maxwell's Equations, is a theory. Creating a simulation of two balls falling would also be formulating a theory. It may be an incorrect theory though, as you point out, and that's where the other leg of science, experimentation (what you refer to as tying back in to the physical world), is necessary. Taking more from your example, I would agree that scientists today are trying to answer questions by diving right into computational models (theory) without experimentation, but I believe it's because they are tackling questions that are very difficult to experiment with. I don't think that's altogether unprecedented though. There are instances of scientists producing theories without the means to test them throughout history, only to have them proven or disproven by experimentation at much later times.
- frossie 16y agoA computational model [...] is a theory I guess that's where we disagree. I respect your point, and of course I accept we are in a regime where computational models are the only options in some cases (we can't start a whole new universe off to see how it worked). That has no bearing on their limitations, though. I think a computational model is not a theory, it is a theoretical construct. I concede this may seem like splitting hairs to everyone except me.
- infinite8s 16y agoI'm confused on the difference between a theoretical construct and a theory.
- krupan 16y agoI think I am too.
- lg 16y agowhen you have good reason to believe something about model-entities, you don't thereby have good reason to believe it about actual-entities, unless you also have good reason to believe that model-entities are relevantly similar to actual-entities. So the model itself is just a piece of a theory.
- jshen 16y agoisn't a model a functional representation of a theory? I don't see how it is only a piece of a theory if the whole theory is represented in the model and is functional.
- lg 16y agoCan you represent the whole theory in the model? The model would need to represent evidence that its representations of the world are accurate. If that evidence is a mathematical proof, a program could probably encode it. But if it's experimental evidence, I don't know how it could.
- barrkel 16y agoThat seems backwards to me. Theories don't "represent" evidence, experimental or otherwise (I'm not even sure what that's supposed to mean, it doesn't make sense to me). You formulate your theory - which is a model of cause and effect - from one set of observations, and test it with another set of observations. The model - the theory - may include facts from experimental evidence, eg G the gravitational constant, but that doesn't seem problematic for theory representation in program form. Theories make predictions about the world. I'd argue they're useless without this. As such, they are function of a prior state, returning the new state. Certainly you can't validate your theory without doing physical experiments, or at least having lots of data that the theory was not based on, to check it. But validation of a theory is distinct from its representation.
- xtacy 16y agoThe example you suggested is probably too simple; one should realise that the actual experiment might be very difficult, if not impossible to carry out. Consider a theory of galaxy collisions---I am unable to see any way of testing out the hypothesis, unless the equations are simple enough. A computer program just a different language of expressing the theory... Hence, I see no reason why one should separate theory and computer programs.
- Retric 16y agoModeling is at best a thought experiment. It can only show you if a theory is reasonably self consistent based on your assumptions not if it's actually true. PS: There are limits on science, and the ability to conduct an actual meaningful exponent is one of the largest ones.
- jshen 16y agoI think there's more to it than that. For example, a model can tell you if something isn't true which is very significant. It can also make predictions that can then be tested. These two alone are much more than a mere thought experiment.
- ynniv 16y agoGreat news! My model tells me that humans no longer have to breathe!
- brg 16y agoI am having a hard time seeing the different. A thought experiment can tell you that if A then B. A model is a means of producing a prediction B from A by means of long, complicated calculations instead of simple logical inferences. In both cases the conclusions should be evaluated before accepted as physical truth.
- jshen 16y agowhat do you believe is the different between a theory and a thought experiment?
- mhb 16y agoSo .. I have a physics problem. I know, I'll write a simulation to solve it. Now I have two problems.
- Aegean 16y agoSo lets define it, its a tool.
- sp332 16y ago"First, neglect air resistance..." http://www.wastedtalent.ca/comic/death-rain1 http://www.wastedtalent.ca/comic/death-rain1