Fundamental issues in science

What follows is an introduction to the discussion of science, and I hope to clear up some misconceptions.  If anyone objects to anything I have to say, then please leave a comment.

First, it is debateable whether or not there is such a thing as proof in science.  We might say for example that John Snow proved that cholera is contracted by drinking contaminated water, or that Sir Ronald Ross proved that malaria is spread by mosquito bites.  However more cautious people might counter that they did not actually prove anything.  John Snow produced substantial evidence to support his belief that cholera is contracted by drinking contaminated water, and Sir Ronald Ross produced substantial evidence to support his belief that malaria is spread by mosquito bites.

It might therefore be more sensible to say that John Snow established that cholera is contracted by drinking contaminated water, or that Sir Ronald Ross established that malaria is spread by mosquito bites.  By established, I mean that they provided the evidence that led to their respective beliefs being widely or perhaps even universally accepted as true in the wider scientific community.

Second, it is important to consider the word theory.  It is sometimes said that scientists do not use the word theory in the same way as ordinary people do, but this is simply not true.  In fact there is a strong likelihood that anyone who says this to you is hoping to deceive you.

Look in any good dictionary, and you will probably find at least half a dozen different definitions of the word theory.   These definitions may or may not include one that is specifically related to science.  However there is no law requiring scientists to adhere to just one of the available definitions.   Any scientist is free to use the word theory in whatever context he considers it appropriate to do so, and he is certainly not restricted to just one possible interpretation.

The word theory is often used in everyday speech to refer to an idea which has yet to be established as either factual or non-factual.  Scientists commonly refer to such an idea as a hypothesis, but the only advantage that hypothesis has over theory is that the latter word is ambiguous.

It is true that scientists often use the word theory to mean an idea that has been subjected to analysis and found to be robust.  An example of a theory by this definition might be gravitational time dilation.  It was the brainchild of Albert Einstein, and was substantiated by the Pound-Rebka experiment.

Nevertheless the title of the BBC television programme Bang Goes The Theory would not make much sense using this definition.  (Purists might argue that the programme ought to be renamed Bang Goes The Hypothesis.)

Consider probability theory.  It is an idea, and therefore a theory.  It has not however been subjected to rigorous analysis, and I’m not sure it could be.   If I consider the likelihood of drawing a particular card from a deck of cards, then probability theory assumes an equal likelihood of each and every possible outcome, but is this assumption reasonable?  Can anyone think of a way to establish that the likelihood of drawing the ace of spades at random from a pack of cards is neither greater nor smaller than the likelihood of drawing the seven of diamonds?  I can’t.

Probability theory has its uses, but it is nonetheless an example of a theory which cannot be substantiated.

It is possible that some readers may find this to be among my least interesting blog posts, but I feel that it would be unwise of me to write about scientific issues in future posts unless I have first addressed certain basic issues.