What does "it's only a theory" mean?

[Dingbat]

1) What is meant by the indefinite article "a"? Between scientists, they say "the theory", not "a theory". For example, it's "The theory of gravity" and "The theory of relativity", not "A theory of gravity" and "A theory of relativity".

2) It's "The theory" because there is room for only one theory for a given phenomenon. If one hypothesis becomes the theory, then other hypotheses are just hypotheses, not theories ... until/ unless the current theory becomes obsolete and some other hypothesis gets upgraded to become the new theory. 

3) If the hypothesis of Intelligent Design comes to be accepted as the method of speciation by the majority of scientists, it would become "The theory of speciation by intelligent design" and there would no longer be "The theory of speciation by evolution"; there would only be "The former theory of speciation by evolution."

4) If scientists were to accept and start teaching "The theory of speciation by intellignet design", then would creationists start saying "Intelligent design is only a theory"? If not, why are they saying "Evolution is only a theory"?

[e_space]

THE one that is accepted by multiple scientists ... 

[John Stockwell]

It suggests that a person might not be clear on what a theory is.

On Thursday, August 21, 2014 2:46:36 PM UTC-6, Dingbat wrote:

1) What is meant by the indefinite article "a"? Between scientists, they say "the theory", not "a theory". For example, it's "The theory of gravity" and "The theory of relativity", not "A theory of gravity" and "A theory of relativity".

Usually "theory" is prefaced by a person's name. For example:    Newton's law of gravity, or Einstein's theory of General relativity.   If there are a collection of theories then usually,
each has its own name, such as the Ekpyrotic cosmological theory versus Big Bang cosmology. Before there was Darwin's theory of evolution by natural selection, there was
Lamarck's theory of evolution by acquired traits.

2) It's "The theory" because there is room for only one theory for a given phenomenon. If one hypothesis becomes the theory, then other hypotheses are just hypotheses, not theories ... until/ unless the current theory becomes obsolete and some other hypothesis gets upgraded to become the new theory. 

If somebody says "the theory of evolution" it is because the dust has settled, and there aren't alternatives in the running for describing the particular phenomena that "the theory"
describes.

3) If the hypothesis of Intelligent Design comes to be accepted as the method of speciation by the majority of scientists, it would become "The theory of speciation by intelligent design" and there would no longer be "The theory of speciation by evolution"; there would only be "The former theory of speciation by evolution."

Theories generate hypotheses. So far, there is neither an hypothesis of intelligent design, nor is there a theory of intelligent design. But suppose there were to become a "theory of
intelligent design", then because the general pattern of biology is consistent with common descent, intelligent design would become another mechanism for mutations. "ID" would
simply become part of our modern notions of evolution.

4) If scientists were to accept and start teaching "The theory of speciation by intellignet design", then would creationists start saying "Intelligent design is only a theory"? If not, why are they saying "Evolution is only a theory"?

Creationists will argue against anything that violates their particular religious notions. If ID were to become part of science, then we would need only do math and science to know
the Designer, and we could chuck all of those religious texts. Hence the (necessarily, highly constrained) ID God is not the same as the one that would find in a traditional religious setting.

-John

[Dingbat]

On Friday, August 22, 2014 3:28:20 PM UTC-4, John Stockwell wrote:

On Thursday, August 21, 2014 2:46:36 PM UTC-6, Dingbat wrote:

1) What is meant by the indefinite article "a"? Between scientists, they say "the theory", not "a theory". For example, it's "The theory of gravity" and "The theory of relativity", not "A theory of gravity" and "A theory of relativity".

Usually "theory" is prefaced by a person's name.

... if that's the least ambiguous way of referring to the theory. In the case of the general theory of relatively, the definite article is more common than Einstein's name. 

https://www.google.com/search?q="the+general+theory+of+relativity"

About 2,940,000 results

https://www.google.com/search?q=%22einstein's+general+theory+of+relativity%22

About 1,860,000 results

[Observer]

Observer

I agree. The following sums it up:

[quote]

http://physics.ucr.edu/~wudka/Physics7/Notes_www/node7.html

What is the difference between a fact, a theory and a hypothesis?

In popular usage, a theory is just a vague and fuzzy sort of fact and a hypothesis is often used as a fancy synonym to `guess'. But to a scientist a theory is a conceptual framework that explains existing observations and predicts new ones. For instance, suppose you see the Sun rise. This is an existing observation which is explained by the theory of gravity proposed by Newton. This theory, in addition to explaining why we see the Sun move across the sky, also explains many other phenomena such as the path followed by the Sun as it moves (as seen from Earth) across the sky, the phases of the Moon, the phases of Venus, the tides, just to mention a few. You can today make a calculation and predict the position of the Sun, the phases of the Moon and Venus, the hour of maximal tide, all 200 years from now. The same theory is used to guide spacecraft all over the Solar System.

A hypothesis is a working assumption. Typically, a scientist devises a hypothesis and then sees if it ``holds water'' by testing it against available data (obtained from previous experiments and observations). If the hypothesis does hold water, the scientist declares it to be a theory.

[\quote]

 

[Dingbat]

If it does hold water better than any competing hypothesis, the scientist proposes it as the (not 'a') theory to his colleagues around the world and if they agree with his claims, they declare it to be the (again, not 'a') theory. The reason for the definite article "the" is that there isn't room for two competing theories to coexist at the same time; only competing hypothesis can coexist. There can be only a single winner at a given time and only that hypothesis gets upgraded to THE theory.