Welp - it seems that I definitely managed to phrase my question poorly. So I'll try again:
By 'atomic theory', I'm referring to the century-plus-old theory that ordinary stuff, like trees and pencils and animals, are made out of something like particles, rather than matter being a 'stuff' that you can just keep on dividing into smaller and smaller pieces. I'm referring to the theory that's the foundation of chemistry.
Put yet another way: "Do you think that 'H2O' is a meaningful description of water?"
Seeing as I work every day with individual DNA molecules which behave discretely (as in, one goes into a cell or one doesn't), and on the way to my advisor I walk past a machine that determines the 3D molecular structure of proteins... yeah.
This edifice not being true would rely on truly convoluted laws of the universe that emulate it in minute detail under every circumstance I can think of, but not doing so under some circumstance not yet seen. I am not sure how to quantify that, but I would certainly never plan for it being the case. >99.9? Most of...
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?".