Final answer:
The Cartesian theory of mind is indeed based on the concept of substance dualism where the mind (immaterial) is distinct from the body (material) and is extended in time but not in space. The statement is therefore True. Descartes' philosophy posits the mind as a non-material, thinking thing, encapsulated by his famous phrase 'Cogito, ergo sum'.
Step-by-step explanation:
The Cartesian theory of mind, as proposed by René Descartes, indeed holds that the mind is a substance that is distinct from the body. This theory, known as substance dualism, suggests that reality is comprised of two fundamental substances: the physical and the spiritual or non-physical. Descartes' view is that the mind, or res cogitans, is an immaterial, thinking substance that is extended in time but not in space, whereas the body, or res extensa, is non-thinking and extended in both time and space.
Therefore, the statement that the Cartesian theory of mind holds that the mind is an immaterial substance that is extended in time but not in space is True. Descartes coined the famous phrase "Cogito, ergo sum" (I think, therefore I am), asserting that the existence of thought implies the existence of a non-material mind. Despite Descartes' argumentation, modern science typically does not support the idea of a mind existing independently from a physical brain.