In my last post of 2013, I gave a problem that provides part of the plot of my ebook novel Athene's Prophecy: how could a Roman prove the heliocentric theory? The short answer is, it was not possible for a Roman to do this directly from then current knowledge. This is a fine example of how you cannot get from A to B directly, but have to through some other places first. That would have been possible, but it did not happen. Why not? The question is of interest because it goes to the heart of what science is about, and that is a more difficult question to answer than you might think, because most scientists do not really have the time to consider it.
 
As an example, during my early working time in an institution, only too much was wasted writing proposals, trying to get funding, trying to keep funding, trying to get or get access to equipment, in other words, doing just about anything except science. Then when I was doing science, the most important thing was to get the material for another paper, because failure to produce enough papers meant failure with the funding, etc. What happened to me was exactly what Kuhn argued would happen: I always started a project that I thought had a very good chance of success.
 
So, back to the question of the title. The first problem would be, why bother? Aristotle was generally believed to be correct, and even if he were wrong in something, who cared? The important point was that the then current theory was splendidly capable of predicting everything of general interest, and, more to the point, it "proved" that the heliocentric theory was wrong. The Ptolemaic model was perfectly adequate for calculating and predicting the timing of things of astronomical, agricultural and religious interest. There was no apparent need to change it. This is where I disagree, because the problem lay in an incorrect understanding of dynamics. As a consequence, their wrong dynamics arguably inhibited progress. I believe that if you understand what is correct, you are more likely to make advances.
 
Aristarchus challenged the "fixed earth" model, but he was hardly rewarded well for what he did, and even now, how many people realize he made more progress than Copernicus? The real problem lay in the proof of the fixed earth model, which relied on experimental proof, in which the observations were interpreted in terms of Aristotle's dynamics, and these were just plain wrong, oddly enough because in getting to them, Aristotle abandoned his own methodology and relied on "the obvious".
 
What Galileo did was to show the "proof" was wrong, he undermined Aristotle's dynamics, and further, he showed the satellites of Jupiter did not fit at all well with the model of Claudius Ptolemy. However, telescopes were not available to my Roman, so he had some work to do. In my next post I shall look at the actual problem in more detail, but in the meantime, how many scientists even now ask themselves whether the conclusions they reach from their experiments could be wrong because the theory they assumed in reaching it could be wrong? Obviously much of our theory is very well tested, but is all of it? Our understanding of electromagnetism is almost certainly correct, so our instruments should give us the correct results, but if we go deeper into our chemical interpretations, how much is actually dependent on a hypothesis that is difficult to test?