A scientific theory is a concise and coherent set of concepts, claims, and laws (frequently expressed mathematically) that can be used to precisely and accurately explain and predict natural phenomena.
A theory should include a mechanism that explains how its concepts, claims, and laws arise from lower-level theories.

A theory, to scientists, means something rather different from its popular use, which suggests something speculative or untested. A scientific theory is a cohesive body of knowledge, an explanation that is consistent among a range of cases and can allow you to predict what might happen in unknown situations.

A theory, is a body of knowledge, that is supportive of, and explanative of facts. Scientific laws are included within a theory, facts are included within a theory, that's why you have the theory of evolution, the theory of gravity, the theory of relativity. There is no concept in creationism, which meets any of the qualifications of a scientific theory, none. You have no facts, you have no laws, you have no evidence, you have no explanative power. All you have, is whatever science can't explain, you pretend you can.

In terms of language, we do know what a scientific theory or conceptual system must be: it is a thematic pattern of semantic relationships in a subject, one that is reconstructed again and again in nearly the same ways by members of a community.

Thus, in scientific research, a great deal of our thinking is in terms of theories. The word ‘theory’ derives from the Greek ‘theoria’, which has the same root as ‘theatre’, in a word meaning ‘to view’ or ‘to make a spectacle’. Thus, it might be said that a theory is primarily a form of insight, i.e. a way of looking at the world, and not a form of knowledge of how the world is.

To say that prediction is the purpose of a scientific theory is to confuse means with ends. It is like saying that the purpose of a spaceship is to burn fuel. … Passing experimental tests is only one of many things a theory has to do to achieve the real purpose of science, which is to explain the world.

Closely related to the erroneous idea that science is a body of knowledge is the equally erroneous idea that scientific theories are true.

Scientific theory is a contrived foothold in the chaos of living phenomena.

Science is a special kind of explanation of the things we see around us. It starts with a problem and curiosity. Something strikes the scientist as odd. It doesn’t fit in with the usual explanation. Maybe harder thinking or more careful observation will resolve the problem. If it remains apuzzle, it stimulates the scientist’s imagination.

There is no such thing as a religious theory, just like science doesn’t promote “non-religious doctrines” either. A doctrine is a set of taught beliefs. Science is an investigation; not a matter of belief.

Science may be defined as the reduction of multiplicity to unity. It seeks to explain the endlessly diverse phenomena of nature by ignoring the uniqueness of particular events, concentrating on what they have in common and finally abstracting some kind of "law," in terms of which they make sense and can be effectively dealt with.

Scientific theories are distinguished from myths... in being criticizable, and... open to modifications... They can be neither verified nor probabilified.

True definition of science: the study of the beauty of the world.

Religion is not a primitive type of scientific theorizing, any more than science is a superior kind of belief-system. Just as rationalists have misunderstood myths as proto-versions of scientific theories, they have made the mistake of believing that scientific theories can be literally true. Both are systems of symbols, metaphors for a reality that cannot be rendered in literal terms. Every spiritual quest concludes in silence, and science also comes to a stop, if by another route. As George Santayana has written, ‘a really naked spirit cannot assume that the world is thoroughly intelligible. There may be surds, there may be hard facts, there may be dark abysses before which intelligence must be silent for fear of going mad.’ Science is like religion, an effort at transcendence that ends by accepting a world that is beyond understanding. All our inquiries come to rest in groundless facts. Just like faith, reason must at last submit; the final end of science is a revelation of the absurd.