Scientist

A scientist is a person with expertise in one or more of the fields of science. Scientists perform research and utilize the scientific method to form hypotheses and to establish theories.

Someone who practices science on a pure theoretical level is known as a theoretical scientist. Once they a develop a theory, they leave its application to others.

Fun Fact:

Star Fleet's most experienced theoretical scientists were consulted on how to allow a sentient hologram to exist outside the holodeck of the USS Enterprise, NCC-1701-D. They did not find a solution.