The atomic theory seems to me very different to me than the others, which seem more like the motivating example. The atomic hypothesis also seems much easier. In particular, I think everyone was in agreement about what it would mean for atoms to be real or not, whereas in the other examples I think that there was no such agreement.
It is true that that the debates used the dichotomy “real or just a useful tool” that appeared in the other examples. Yes, what they meant by “real” was “is it useful in a less circumscribed setting,” but the setting for the atomic theory was very cleanly circumscribed: the law of multiple proportions. It seemed back then (and seems to me) quite plausible that some other underlying phenomenon could give rise to that law. The discovery of another consequence that seemed much less plausibly explained by (hypothetical) other theories brought about rapid acceptance of the theory. (Quantization of charge would have done well here, but I believe the actual consequence was in explaining isomers and especially stereoisomers, which is a scale-free phenomenon, like ratios, but unlike quantization of charge.)
In the other examples, it was not clear what the competing theories were and whether they were distinguishable. Of course, since there was no particular theory competing with the atomic theory, there was danger of the situation becoming muddier, but that doesn’t bother me so much.
The atomic theory seems to me very different to me than the others, which seem more like the motivating example. The atomic hypothesis also seems much easier. In particular, I think everyone was in agreement about what it would mean for atoms to be real or not, whereas in the other examples I think that there was no such agreement.
It is true that that the debates used the dichotomy “real or just a useful tool” that appeared in the other examples. Yes, what they meant by “real” was “is it useful in a less circumscribed setting,” but the setting for the atomic theory was very cleanly circumscribed: the law of multiple proportions. It seemed back then (and seems to me) quite plausible that some other underlying phenomenon could give rise to that law. The discovery of another consequence that seemed much less plausibly explained by (hypothetical) other theories brought about rapid acceptance of the theory. (Quantization of charge would have done well here, but I believe the actual consequence was in explaining isomers and especially stereoisomers, which is a scale-free phenomenon, like ratios, but unlike quantization of charge.)
In the other examples, it was not clear what the competing theories were and whether they were distinguishable. Of course, since there was no particular theory competing with the atomic theory, there was danger of the situation becoming muddier, but that doesn’t bother me so much.