How much confidence do you place in the scientific theory that ordinary matter is made of discrete units, or 'atoms', as opposed to being infinitely divisible?
More than 50%? 90%? 99%? 99.9%? 99.99%? 99.999%? More? If so, how much more? (If describing your answer in percentages is cumbersome, then feel free to use the logarithmic scale of decibans, where 10 decibans corresponds to 90% confidence, 20 to 99%, 30 to 99.9%, etc.)
This question freely acknowledges that there are aspects of physics which the atomic theory does not directly cover, such as conditions of extremely high energy. This question is primarily concerned with that portion of physics in which the atomic theory makes testable predictions.
This question also freely acknowledges that its current phrasing and presentation may not be the best possible to elicit answers from the LessWrong community, and will be happy to accept suggestions for improvement.
Edit: By 'atomic theory', this question refers to the century-plus-old theory. A reasonably accurate rewording is: "Do you believe 'H2O' is a meaningful description of water?".
For many of the obvious ways to pose the question, atomic theory is already false - multiparticle states are the real building blocks, and you can do pretty unusual things with them if you try hard enough. I think the most sensible thing to ask about is sudden failure of properties that we normally ascribe to atomic theory, like ratios working in chemical reactions or quantum mechanics predicting NMR spectra. In which case, I'd need said failures to replicate to be as good as the supporting evidence, or propose a simple-ish mechanism, like "we're in a simulation and it's just changed." Taking that as my lowest standard, I'd be satisfied with a standard star-blinking pattern, or maybe a pi-message, the usual sort of thing, with null probability with an exponent somewhere in the -25 range.