In general, do not capitalize the words in names of theories. Capitalize only people's names, for example, Gardner's theory of multiple intelligences and the cognitive learning theory.

Is the name of a theory a proper noun?

For a law or theory named after its originator, capitalize the proper noun, but do not capitalize the name of the law or theory, whether it is used together with the name or alone: ... the general theory of relativity. the second law of thermodynamics.

Should theories be capitalized MLA?

Theories aren't capitalized or highlighted with italics, but you do capitalize someone's name when it's part of a theory: Dr. Goodman's theory of whole language. Einstein's general theory of relativity.