In science, a theory is a set of ideas, concepts, principles, or methods used to explain a wide set of observed facts. [1] The following is a noted quote on theories in general by Arthur Eddington, from his 1928 The Nature of the Physical World: [2]

“If someone points out to you that your pet theory of the universe is in disagreement with Maxwell’s equations — then so much the worse for Maxwell's equations. If it is found to be contradicted by observation — well, these experimentalists do bungle things sometimes. But if your theory is found to be against the second law of thermodynamics I can give you no hope; there is nothing for it but to collapse in deepest humiliation.”

which generally means that any theory that contradicts the second law is in fact a defunct theory.

Examples
Theories connected to the subject of thermodynamics, human thermodynamics, chemistry, or human chemistry include: caloric theory, mechanical theory, theory of heat, kinetic theory, information theory, collision theory, mechanical theory of heat, reaction match theory, Porteus theory of happiness, combination lock theory, endorphin theory of love, thermodynamic theory of the evolution of living beings, human molecular orbital theory, among others.

References
1. Clark, John O.E. (2004). The Essential Dictionary of Science. Barnes & Noble.
2. Eddington, Arthur S. (1928). The Nature of the Physical World (pg. 74). Cambridge: Cambridge University Press.

Further reading
‚óŹ Bothamley, Jennifer. (2002). Dictionary of Theories: One Stop to more than 5,000 Theories. Visible Ink Press.

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