Theory and research have a complex interrelationship. Theories generate hypotheses that can be proven or disproved by research, the results of which may cause the theory to be strengthened. The results of research may also call a theory into question, causing it to be rejected or revised.
A theory is a widely accepted principle or explanation of nature. In science, a theory is the most reliable form of knowledge. It is expressed in a logical form and based on substantial evidence. Examples of scientific theory include the heliocentric theory that the Earth rotates around the sun, the cell theory that living things are composed of cells and the theory of plate tectonics that explains the movement of solid plates comprising the surface of the Earth. Research is creative work used to increase the knowledge available to humankind. Both theory and research are part of the scientific method, a process by which knowledge is acquired, corrected and integrated into the totality of verifiable knowledge.
A theory is not the same as a hypothesis, which is a testable prediction made before carrying out research. A hypothesis is an idea that has yet to be tested, whereas a theory has already been tested, supported and generally accepted. A hypothesis is focused on a specific set of circumstances, while a theory is a more general explanation or observation.