"The struggle for existence holds as much in the intellectual as in the physical world. A theory is a species of thinking, and its right to exist is coextensive with its power of resisting extinction by its rivals"

This quote by Thomas Huxley talks to the concept that competitors is a part of life, both in the physical and intellectual worlds. Huxley is suggesting that a theory, or concept, must be able to withstand the competition of other ideas in order to endure. He is stating that a theory needs to be strong enough to withstand extinction by its competitors in order to exist. This quote talks to the idea that competitors is a part of life, and that in order to survive, one must be able to compete and prove their worth. Huxley's quote is a pointer that in order to prosper, one must be able to stand up to the competitors and prove their worth.