Step 1: Concept Identification:
The inquiry seeks the philosopher who advanced mind-body dualism, the tenet that the non-physical soul or mind can persist independently of the physical body.
Step 2: Detailed Analysis:
(A) Plato: An ancient Greek philosopher, Plato vigorously supported dualism. He posited the soul as immortal and capable of existing apart from the body, both pre-birth and post-death. His dialogue, *Phaedo*, specifically details arguments for the soul's immortality and its distinctness from the body.
(B) De Anima: This is not an individual but the title of a significant work by Aristotle ("On the Soul"). Aristotle, Plato's student, held a divergent view, considering the soul the "form" of the body, incapable of independent existence, thereby contradicting dualism.
(C) Rene Descartes: A 17th-century philosopher, Descartes is also a prominent dualist. His assertion, "I think, therefore I am," established the mind as a thinking entity, separate from the corporeal, extended body. Although Descartes exemplifies dualism, Plato's foundational ideas on this subject preceded his by centuries, making Plato the historically primary proponent.
(D) Gustav Fechner: A 19th-century German psychologist, Fechner is recognized as a pioneer of psychophysics, the study of the relationship between physical stimuli and sensory perception. His work does not primarily address the metaphysical concept of the soul's separation from the body.
Step 3: Conclusion:
Given the foundational and explicit arguments for the soul's independent existence, Plato is the accurate answer.