Here is an interesting discussion on how the word "theory" has changed from the original meaning of "a set of principles that has been verified" to "a belief, proposal or hypothesis." In looking at the various online definitions, I see that this is true. While the first definition is usually related to the original one, the later ones often say that it is a proposed set of principles. For example, the second definition from WordNet (1997 Princeton University) is "a concept that is not yet verified but that if true would explain certain facts or phenomena."

Interestingly, the following quote is from the online Webster's Unabridged Dictionary:

``This word is employed by English writers in a very loose and improper sense. It is with them usually convertible into hypothesis, and hypothesis is commonly used as another term for conjecture. The terms theory and theoretical are properly used in opposition to the terms practice and practical. In this sense, they were exclusively employed by the ancients; and in this sense, they are almost exclusively employed by the Continental philosophers.'' --Sir W. Hamilton.

What are your thoughts?

I agree with the article completely. Many words start off with a specific scientific meaning and eventually escape to the general population, becoming watered down, often expanded and greatly simplified. This can be aggravating to the specialist in the field, for this simplified meaning becomes entrenched in the vocabulary. Sometimes even some specialists adopt the new difinition. Then you may have a situation in which two scientists in the field use the same word, but with different meanings.

There are also words that start out in the general vernacular and are adopted with a specific meaning by specialized group.

This occurs not only in science, but in virtually any specialized field of knowledge. I'm sure many of you can think of examples.

Tinman

It definitely has occurred in nursing. We have whole courses at the graduate level entitled, "Nursing Theory." Now I realize that none of the nursing theories have been verified.

As I recall, any scientific principle goes through three stages:

A hypotheses; a theory; a law.

How much proof is needed for progression through the stages I don't know but I can think of some that seem to have stuck halfway - the theory of evolution, for example.

Would I be right in assuming that it won't become the law of evolution until sufficient instances of evolution have been seen and verified for the theory to be judged accurate?

In science a theory is a body of principles that collectively explain a subject: so the theories of electromagnetics, gravitation, evolution, genetics, quantum mechanics, strings, fluid dynamics etc. It doesn't have to be of a whole major field: there can be a theory of black holes, as long as it's a connected and coherent body of understanding of how they work.

It's interesting to note that the OED lists a fedw definitions of theory earlier than the classic scientific one: 1. A sight, a spectacle. 2. Mental view, contemplation. 3. A conception or metnal scheme of something to be done, or of the method of doing it; a systematic statement of rules or principles to be followed. So, it seems that the scientists took a perfectly good English word and twisted its meaning to their purposes. This is usually true of specialist jargon. (My personal favorite is file, which has gone from meaning a thread used to hold together papers to an array of bytes stored on a fixed memeory device.) One has only to look at most entries in a dictionary to realize that words with a single meaning are very rare indeed.

One has only to look at most entries in a dictionary to realize that words with a single meaning are very rare indeed.
Yes, I know that. However, it isn't common (though I have seen it) where the definition has changed, as the engines episode says, from one meaning to almost the opposite. There is a big difference between an hypothesis and a set of principles that have been verified.

The problem of communication then arises. To which definition is the writer or speaker referring? For example, when we speak of "nursing theories," one discipline might think these theories have all been rigorously tested. They surely have not been. I worked with the professor who concocted (yes, concocted!) the Parse Human Becoming Theory. The terminology of this theory is so complex that it is almost incomprehensible unless you work with the theory on a daily basis. In fact, there are many competing nursing theories, none of which that have been verified, and they all purport to explain nursing.