Theory is a commonly used word necessary to explain some fundamental ideas. In science there are three words commonly used to describe such ideas depending on the degree of certainty – hypothesis, theory and law.
A hypothesis is an assumption, an idea that is proposed for the sake of argument so that it can be tested to see if it might be true.
A theory, in contrast, is a principle that has been formed as an attempt to explain things that have already been substantiated by data.
A law in science applies to principles so firmly established that they are almost never questioned, such as the law of gravity. Furthermore the syntax of the uses of the word law means that it is usually very clear which context one is using the word, whether in politics, the judiciary and courts, religion or science.
The meanings of the words hypothesis and law are indisputable. In comparison here is a look at Merriam Webster´s definition of the word theory – (April 2022 version below)
theory – noun
Merriam-webster dictionary
the· o· ry | \ ˈthē-ə-rē, ˈthir-ē \
plural theories
Definition of Theory
- a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena
e.g. the wave theory of light - a : a belief, policy, or procedure proposed or followed as the basis of action
e.g. her method is based on the theory that all children want to learn
b : an ideal or hypothetical set of facts, principles, or circumstances —often used in the phrase in theory
e.g. in theory, we have always advocated freedom for all - a : a hypothesis assumed for the sake of argument or investigation
b : an unproved assumption : conjecture
c : a body of theorems presenting a concise systematic view of a subject
e.g. theory of equations - the general or abstract principles of a body of fact, a science, or an art
e.g. music theory
abstract thought : speculation
the analysis of a set of facts in their relation to one another
It is both strange and unfortunate that a commonly used word can mean both of these opposing concepts –
- scientifically acceptable general principle or body of principles offered to explain phenomena. Which in short means true or the closest to the truth that we have for now, until another better idea or explanation arises.
- an unproved assumption, conjecture, speculation or abstract thought. This meaning has no basis in truth, nor does it aspire to be true.
The Merriam Webster page responsibly addresses this discrepancy in its article later, by diplomatically understating the difference in meaning as being sometimes troublesome. –
Two Related, Yet Distinct, Meanings of Theory
There are many shades of meaning to the word theory. Most of these are used without difficulty, and we understand, based on the context in which they are found, what the intended meaning is. For instance, when we speak of music theory we understand it to be in reference to the underlying principles of the composition of music, and not in reference to some speculation about those principles.
However, there are two senses of theory which are sometimes troublesome. These are the senses which are defined as “a plausible or scientifically acceptable general principle or body of principles offered to explain phenomena” and “an unproven assumption; conjecture.” The second of these is occasionally misapplied in cases where the former is meant, as when a particular scientific theory is derided as “just a theory,” implying that it is no more than speculation or conjecture. One may certainly disagree with scientists regarding their theories, but it is an inaccurate interpretation of language to regard their use of the word as implying a tentative hypothesis; the scientific use of theory is quite different than the speculative use of the word.
They explain this in more detail using an example –
The distinction has come to the forefront particularly on occasions when the content of science curricula in schools has been challenged—notably, when a school board in Georgia put stickers on textbooks stating that evolution was “a theory, not a fact, regarding the origin of living things.” As Kenneth R. Miller, a cell biologist at Brown University, has said, a theory “doesn’t mean a hunch or a guess. A theory is a system of explanations that ties together a whole bunch of facts. It not only explains those facts, but predicts what you ought to find from other observations and experiments.”
While theories are never completely infallible, they form the basis of scientific reasoning because, as Miller said “to the best of our ability, we’ve tested them, and they’ve held up.”
I think this use of one word for opposite meanings is tragic. This is especially so because many education systems fail to distinguish this difference, and we are living in times when our understanding of the meaning of the scientific theory is essential. Only by doing so can we make good decisions about the environment or climate change, for example. When I use theory in this context I will include explanation in brackets to try and distinguish it from hunch or idea. The science community should think of a new word for the scientific meaning.