Final answer:
Existentialism is the philosophy that does not imply people are merely physical beings with no spirit or soul, contrasting with materialism, physicalism, and naturalism which focus only on physical existence.
Step-by-step explanation:
Among the philosophical perspectives mentioned, existentialism stands out as the term that does not imply that there is nothing but matter and that people are merely physical beings with no spirit or soul.
Materialism and physicalism both assert that only material or physical substances exist, thereby excluding any non-physical substance such as a soul or spirit from reality. Naturalism shares a similar view, focusing only on physical entities and the laws that govern them, rejecting metaphysics and spiritual realms that are beyond empirical proof.
Unlike these perspectives, existentialism does not necessarily deny the existence of the non-physical; instead, it concerns itself with the existence of individuals as free beings responsible for their own actions in a universe devoid of inherent meaning.