Part 4/10:
In Spinoza's philosophy, everything that exists embodies both thought and extension—his terms for mental and physical aspects of existence, respectively. This radical assertion means that even a simple rock possesses a physical form (extension) while also reflecting a corresponding mental or ideal aspect (thought). The complexity of thought increases in humans, giving rise to what we experience as mind and body.
Thus, Spinoza envisioned a universe in which the mental and the physical are intricately connected, essential parts of the same reality. This insight prompts us to reconsider our perception of ourselves and our relationship to the cosmos.