In the most recent instalment of the Oxford History of Chemistry Seminar, I was intrigued by the story of the "distance problem" which remained unresolved for the entire length of the 19th century. As Hasok Chang reminded us, electricity and the electrolysis of water was known at the beginning of the century, and people were puzzled to see that if the two electrodes of a battery are immersed in water, a few inches apart, the oxygen will only develop on one side and the hydrogen only on the other. If it was true that water was a compound of oxygen and hydrogen, and if that compound was split up by electricity, how could the fragments turn up in different places ???
According to Chang, who is preparing a book about the history of research relating to water, the problem was debated throughout the 19th century, with wildly different hypotheses being brought forward. So for a long time there was a pluralism of interpretations, not a paradigm shift in Kuhnian terms.
It reminded me a lot of today's big open questions such as dark matter and dark energy, where we also have a very colourful collection of hypotheses but simply haven't got the right tools (yet) to get a definitive answer. Maybe if he manages to make the distance problem in water more widely known, this would help people understand that science doesn't always have a definitive answer for everything. After all it is important to understand the uncertainty in science, e.g. the uncertainty as to what will happen with the H1N1 "swine flu" virus.