theorist; theoretician; doctrinaire; an expert who engages in theoretical research or uses a system of ideas to solve practical problems

The quality of having a systematic set of arguments or a theoretical basis; theorization

rationalism; a philosophical theory that emphasizes reason as the primary source of knowledge

the branch of theory focused on qualitative properties rather than numerical quantities

string theory in physics

the psychological theory that explains how individuals interpret and assign causes for their own behavior and the behavior of others

A theory of leadership and management stating that there is no single best way to organize a corporation or to lead a company, but that the style should fit the specific situation.

a fundamental branch of modern algebraic geometry developed by Alexander Grothendieck

the psychological or scientific theory that the mind or a system is composed of distinct, specialized components or modules

fuzzy logic or fuzzy set theory; a mathematical system established by Lotfi A. Zadeh in 1965 that models human reasoning and perception by using imprecise or approximate data instead of traditional binary values

the philosophical theory that everything in the universe is rational and can be understood through reason; panlogism

(math) a branch of mathematics dealing with complex systems whose behavior is highly sensitive to slight changes in conditions

in theory; used when considering only the ideas behind something without accounting for practical facts or other factors

The core ideas or principles that a theory is built upon

the advancement of knowledge or conceptual understanding within a specific academic field

the physical theory of electromagnetism

The theory in cosmology that the universe is always expanding but maintains a constant average density.

(math) catastrophe theory

pure theory; a theoretical or philosophical framework based solely on reason rather than empirical evidence or practical application

structural theory, especially within the field of physics

theory of translation

a type of field theory in physics where the Lagrangian is invariant under local transformations from a certain group (gauge symmetry)

The series of political and economic ideologies first developed by [[邓小平|鄧小平|deng4 xiao3 ping2]]; it forms the basis for the economic reforms of China starting in the late 1970s.

the branch of physics that describes the behavior of matter and energy on the atomic and subatomic scale; same as quantum mechanics

Maslow's hierarchy of needs, a theory in psychology proposed by Abraham Maslow

the branch of mathematics that connects field theory and group theory, named after Évariste Galois

political theory that if one country in a region falls to an opposing ideology, nearby countries will follow in a chain reaction; originally proposed by U.S. President Eisenhower regarding Southeast Asia

the mathematical theory of fields and symmetry named after Évariste Galois

phenomenological theory; a theoretical approach in physics that focuses on describing observable phenomena without necessarily explaining their underlying causes