Final answer:
Descartes believed the pineal gland was the link between the rational soul and the mechanical body, a notion now disproven by science which confirms the brain's physical structures are essential for thought.
Step-by-step explanation:
Descartes suggested that the rational soul was able to control the mechanical body by having both functions come together in a structure of the brain called the pineal gland. In his view, the pineal gland was the master control unit where the soul contacted the brain (body), as it was singular and not doubled like other parts of the brain. However, scientific investigation has now proven that the pineal gland does not function as a central control unit for the brain.The brain itself is the control center of the nervous system and is divided into three major parts: the brain stem, cerebellum, and cerebrum, with the cerebrum being the largest part of the brain. The cerebrum controls functions such as reasoning, speech, voluntary movements, and sensory perception. Inner structures of the brain include the hypothalamus and thalamus, which play important roles in involuntary functions and endocrine control.René Descartes also held a dualistic view of reality, separating it into matter/physical and spirit/non-physical. His famous claim "I think, therefore I am" was intended to establish that the existence of a thinking thing, which he equated with the soul, did not require a physical body. However, modern science contradicts Descartes' perspective, as there is extensive evidence that thought is inextricably linked to the physical structure and functioning of the brain.