What is the difference between a scientific theory and established scientific knowledge?

Answer 1

In many ways there are no differences. I am not a scientist, but an interested and informed 'layman'. We should make some distinctions among different kinds of 'knowledge'. At one time in history, probably no person ever seriously thought that we would walk on another world (the moon) or be able to directly observe the planets. There were some interesting theories about how the planets moved in the skies long before we had a grasp of gravity. Some of these old planetary theories (mathematical systems rather than theories, really) had amazingly accurate predictive value. You could show where a planet would be at a given future time, and always be right. According to those earth-centered systems, though, the planets were moving in all kinds of swirling, eccenric ways (resulting from the obligatory geo-centric starting point). Those models of planetary motion were completely off base, even though the systems could make excellent predictions. The models were theoretical, and the thinkers who developed them had every reason to believe they would always be theoretical. We know now, not just because much better models were developed, but by direct observation, that the sun is at the center. We can make predictions too, but have irrefutable evidence about the basic, gross movement of planets. Some might argue that this means the geocentric 'theory' is now proven, and that the geocentric 'theory' is now 'established knowledge'. After all, no person in his/her right mind will seriously rush to the telescope tonight hoping to find Jupiter orbiting clockwise now, instead of anticlockwise. I think it is closer to the truth to say that what was once considered theoretical regarding gross planetary motion has now left the realm of theory altogether and has become a simple, common observation that would not be denied by any informed competent person. A great deal of scientific knowledge fits into this picture; many of the more immediately observable realities of the world do not require knowledge of a deeper theory in order to believe them and to consider them 'established'. However, there is another level of theory that is not so easily written off. Given the obvious gross motion of the planets, there is the awesome reality that something is maintaining this motion. We know (for the time being, at any rate) that this something is gravity, and there are some fascinating theories about how it works, and what it is. You can see that this kind of theory is different in nature from the 'theories' of planetary motion that the ancient thinkers developed. We are not likely to ever 'see' gravity, or the quantum, string and m-theories that are being studied along with it. Relativity and Quantum theory have strong predictive power, and each has inspired fascinating research. Are we ready to say that these 'theories' are 'established' scientific knowledge? I say no, we are not. I would come to the same conclusion about what we call the 'Big Bang', and Evolution, and a few others. These deep, invisible theoretical frameworks are and will forever remain theoretical, because the process of science itself (the heuristic we call the scientific method) does NOT contain any end-point, a way of testing a theory to indicate that absolute, forever irrefutable truth has been revealed. The theories that hold up to the test of time (and armies of scientists who would destroy them) usually end up enjoying a measure of stability; some of them even become 'laws'. But if the work of a scientist of Newton's mythical stature can be challenged and shown to be in many ways fundamentally wrong after centuries of dominance, then what theory can ever be demonstrated to be beyond challenge? Whatever scientific knowledge that is dependent upon a deep theoretical structure, even if it is considered 'established' today, may become the center of the next world-changing scientific revolution tomorrow.