One of the most frustrating thing when having arguments with supposedly university educated people is when they retort: it’s just a theory. Escaping this rancid anti-intellectualism should be the least of which you learn in a university education but I found this not to be so so many times. I would fear for the continuity of the Age of Enlightenment every time I heard these words uttered.
A scientific theory is not just an idea that lives in someone’s head, rather than an explanation rooted in experiment and testing. Scientific theories are central to the growth of knowledge which itself grows through criticism and discussion:
If we are uncritical we shall always find what we want: we shall look for, and find, confirmations, and we shall look away from, and not see, whatever might be dangerous to our pet theories.
In this way it is only too easy to obtain what appears to be overwhelming evidence in favour of a theory which, if approached critically, would have been refuted – Karl Popper
A theory is an explanation or model based on observation, experimentation, and reasoning, especially one that has been tested and confirmed as a general principle helping to explain and predict natural phenomena.
When I speak of reason or rationalism, all I mean is the conviction that we can learn through criticism of our mistakes and errors, especially through criticism by others, and eventually also through self-criticism.
A rationalist is simply someone for whom it is more important to learn than to be proved right; someone who is willing to learn from others — not by simply taking over another’s opinions, but by gladly allowing others to criticize his ideas and by gladly criticizing the ideas of others. The emphasis here is on the idea of criticism or, to be more precise, critical discussion – Karl Popper
Any scientific theory must be based on a careful and rational examination of the facts.