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Author Topic:   What is a theory in biology?
Posts: 20111
From: the other end of the sidewalk
Joined: 03-14-2004
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Message 16 of 22 (204778)
05-03-2005 8:18 PM
Reply to: Message 15 by mick
05-03-2005 8:02 PM

excellent point.

the other side of this issue is that predictions made by scientific theories are usually developed to differentiate one theory from another or in some way {validate or falsify} the theory, and not to amuse anyone. thus they tend to be rather mundane. but gooood mundane. :D

we are limited in our ability to understand
by our ability to understand

{{{Buddha walks off laughing with joy}}}

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Posts: 326
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Message 17 of 22 (204891)
05-04-2005 7:51 AM
Reply to: Message 9 by New Cat's Eye
05-03-2005 7:28 PM

I asked a question about what we could evolve into, or where evolution was taking us, (which I later realised was asking the theory to make a prediction {a fundamental part of scientific theories}), I got this answer:

Just to add to other replies, the reason asking this question is not productive is because you're asking the TOE to predict something that is unpredictable. Mutations are random, and the environment will likely be chatoic in the long term.

As an example of another theory that works with randomness, take QM. If you have an X-Ray Diffraction experiment and fire one single electron at the gap, it is not possible to predict where the electron will end up. All that can be done is say that it is more likely to end up in one place over another. This doesn't mean that QM is not a valid theory or is not scientific, it just means that it can't make the kind of prediction you want.

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Message 18 of 22 (204932)
05-04-2005 10:39 AM

Hmm, I dunno.

The objection that prediction is not of future events does not fly. Prediction is a powerful tool BECAUSE it does indeed predict - that is, state before - what the result will be. If it did not do so, it would not be valid as an experimental process.

But, these predictions are extremely constrained, in order that we do not over-draw our conclusions. Thats why such lab predictions are not smoothly generalisable to real, open environment future events.

But that too said, I think that with a good enough understanding of biological mechanics, we might eventually be able to build a predictive model. That is, there must be a limited range of solutions available to biological organisms as a result of the properties of the materials of which they are comprised. This would still not produce the constrained prediction of an experiment, but should permit probablistic predictions.

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Message 19 of 22 (204966)
05-04-2005 1:06 PM
Reply to: Message 18 by contracycle
05-04-2005 10:39 AM

contracycle, I suppose you're right that we do predict the future but just in a very constrained way.

The fact that, when we predict the outcome of an experiment, our experiments haven't taken place yet, means that we are predicting the future, but only in a trivial way.

But yes, we can already make more long term predictions based on the theory of evolution. For example, population processes will cause the amount of heterozygosity in panda bear populations to decline over the next few decades; while introgression is going to make the amount of heterozygosity in wildcat populations increase. We can probably predict extinction risk quite accurately for many species based on their ecology and demography; etc.

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Message 20 of 22 (207131)
05-11-2005 2:01 PM

Quick question from a non-scientist. Can a theory be considered a working model that, well supported by previously gathered evidence, provides scientists with an explanatory framework out of which they can generate hypotheses?
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Message 21 of 22 (207156)
05-11-2005 3:10 PM
Reply to: Message 3 by mick
05-03-2005 12:29 PM

you are using theory in place of hypothesis. a hypothesis is a conjecture about the state of things. a theory is a hypothesis that has been proven once and is up for repeat until people are satisfied that it holds. then it becomes law.
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From: A wheatfield in Kansas
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Message 22 of 22 (207164)
05-11-2005 3:38 PM
Reply to: Message 21 by macaroniandcheese
05-11-2005 3:10 PM

brennakimi writes:

a theory is a hypothesis that has been proven once and is up for repeat until people are satisfied that it holds. then it becomes law

Sorry but no.
It is hard to improve on Mick's explanation, but maybe this will help.

In the strict scientific sense, a hypothesis is simply a conjecture, hopefully phrased so as to be both testable and falsifiable.

It is never proven nor disproven, only supported or unsupported by evidence.

Think of hypotheses as little testable bits that contribute to framing a theory.

No hypothesis can ever become a law, although a theory, in principle, could.

A law, in the scientific sense, is a simple, immutable, mathematically definable relationship between specific variables that never changes.
Most scientific laws pertain to physics - not biology.

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