He was a fatalist, believing that all events are determined by fate.

Syntax is a branch of linguistics.

He is majoring in syntax at university.

He strongly advocated the theory of southward advancement.

He strongly advocated the hokushin theory.

He believes in teleology, thinking that there is a meaning in every event.

Category theory is a branch of mathematics that studies structures and their relationships.

He is an expert in probability theory.

Einstein's theory of relativity is one of the important theories in physics.

A DD debate is unfolding between him and her.