What does a "Theory" mean in Science?

[Gordon Freynman]

What I hope to do here is explain exactly what a theory means to science and how it relates with facts, evidence, and hypothesises (in science as well).

I often see the word "theory" implied as being a guess, i.e. "it's only a theory" "all they have is a bunch of theories," but this is a complete misapplication of the term, and most of blame for this would have to go to the popular media which frequently extrapolates it to situations where it shouldn't be used. What a theory is in scientific terms is a collection of concepts that are used to explain observed phenomena in nature. In order for a theory to be valid it must be testable, falsifiable, and make predictions about potential future observations. In physics the definition of a theory is slightly different, in that the explanation of observed phenomena is usually in the form of a mathematical framework. However it still has to have all the basic requirements of theory to actually be called a theory.

The difference between a fact and a theory (in science) is that a fact is something that is known to be true to by objective and verifiable observation, and a theory is the explanation used for facts, (so is a hypothesis but more on that a little later). For example, it is an observable fact that objects with mass have a tendency to attract one another, and the amount of attraction between objects increases as the mass increases and decreases as distance between the objects increases. The most accurate theory to date used to describe this fact is of course Einstein's Theory of General Relativity.

The difference between a hypothesis and a theory, is that a hypothesis is simply a theory which has yet to be tested. A hypothesis is developed to explain an observational phenomena, and through various sorts of experiments the hypothesis is either shown to be valid or not. If it is shown to be valid, then it is one step closer to becoming a theory (usually a hypothesis will need further development and testing to become a fully fledged theory).

I think that does it for a short and concise explanation of a scientific theory. Questions and suggestions for improvement are always welcome!

[Pontifex Maximus]

A theory is an integrated explanation of numerous hypotheses, each of which is supported by a large body of observations and experiments.

So, basically, when someone says they don't believe or agree with a scientific theory, such as evolution, they are willingly turning their backs on hypotheses proven to be true by experimentation and observations.

[Vagn]

Here's a quote about what a theory is from an undergraduate Physics textbook I have:

"Calling an idea a theory does not mean that it's just a random thought or unproven concept. Rather a theory is an explanation of natural phenomena based on observation and accepted fundamental principles. An example is the well-established theory of biological evolution, which is the result of extensive research and observation by generations of biologists."

[SoggyFrog]

So, basically, when someone says they don't believe or agree with a scientific theory, such as evolution, they are willingly turning their backs on hypotheses proven to be true by experimentation and observations.

Never make the mistake of saying that a hypothesis can be proven true, they're only tested. The probem is that people think that this indicates weakness in the scientific method and scientific theories, but it's actually its strength.

[Banana Jelly]

In theory, what you say is correct; but in practice... no.






anyone get the joke?

[Gordon Freynman]

In theory, what you say is correct; but in practice... no.






anyone get the joke?

Here's a better joke: Theoretical physicists always know the answer, and sometimes they're right!