“Entropy depends not on the difference between the gases, but on their distinguishability.”
Sadi Carnot sold his 118-page book on steam engines for 3 francs in 1824, and the scientific establishment ignored it. E.T. Jaynes argued in 1957 that entropy measures the observer’s ignorance, not a property of the system. Physicists have spent decades resisting that because it makes their science about what you know rather than what is. Anthony Aguirre puts it bluntly: physicists are allergic to subjectivity.