Spinoza & Leibniz: Rationalism, Substance, and Monads
Spinoza’s Philosophy
Rational Spirit
Spinoza’s philosophy is based on modern rationalism. Mathematical deduction is considered the highest form of rationality. Rationality allows us access to reality more rigorously. Spinoza first establishes definitions, sets a series of axioms, and thereafter devotes himself to obtaining various propositions whose truth is demonstrated by applying deductive logic. For Spinoza, genuine knowledge is knowledge by causes. It follows a logical order, from the universal to the particular.
Substantial Monism
For Descartes, substance was a reality that needs no other reality to exist. From this definition, Spinoza argues there is only one substance, not three (as Descartes proposed with God, mind, and matter). Both thinking substance (res cogitans) and extended substance (res extensa) require an infinite substance to exist. Therefore, only God is truly substance. Spinoza distinguishes between Natura naturans (nature naturing) and Natura naturata (nature natured):
- Natura naturans: The creative nature, i.e., God as infinite substance.
- Natura naturata: The created nature, the set of all individual realities (modes).
Spinoza clarifies that creation is a natural, necessary expression of God’s essence; God expresses reality by creating.
Ethics and Happiness
The soul-body dualism expressed by Descartes is surpassed in Spinoza, who states that the soul and body are one and the same thing (aspects of the single substance, God). Man seeks not only to survive but also tranquility of spirit through knowledge. Virtue is living adequately under the guidance of reason, understanding and overcoming our passions, i.e., doing what best suits our nature. The key to a happy life lies in having adequate ideas in our understanding. Happiness is thus related to intellectual understanding (the intellectual love of God).
Freedom
Freedom is linked with the necessity of nature. For Spinoza, a person is free not when they act arbitrarily, but when they understand the necessity of the nature of things (including their own nature) and accept it, acting in accordance with reason.
Leibniz’s Philosophy
Theory of Knowledge
Leibniz accepts the importance of the senses in the process of knowledge but, like a rationalist, also considers that the mind imposes certain innate principles or structures. Leibniz accepts the existence of innate ideas, such as the idea of God. A significant contribution of Leibniz is the distinction between two types of truths:
- Truths of Reason: These are necessary truths where the predicate is contained within the subject (analytic). Their denial implies a contradiction (e.g., “triangles have three sides”). They are known a priori.
- Truths of Fact: These are contingent truths where the predicate is not contained within the subject’s definition (synthetic). Their denial is possible without contradiction (e.g., “Caesar crossed the Rubicon”). They are known a posteriori, through observation, though ultimately grounded in God’s choice of the best possible world (Principle of Sufficient Reason).
According to Leibniz, the world of logic (necessary truths) is distinct from the world of contingent things.
Monads
Leibniz argued that a major mistake of Descartes was conceiving matter merely as extension, forgetting that nature possesses inherent force or activity. For Leibniz, reality is fundamentally dynamism, force, and energy. Beneath the appearance of extension, reality is composed of simple, indivisible, non-extended substances or energy points called monads. Monads are the fundamental elements of reality, endowed with perception and appetition (striving).
Preestablished Harmony
For Leibniz, monads are “windowless” – they do not causally interact with each other. Instead, God, in creating the universe, established a perfect harmony among all monads from the beginning. Each monad unfolds its own predetermined sequence of perceptions and actions according to its internal law, perfectly corresponding with the states of all other monads. Leibniz uses the analogy of God as the great clockmaker who synchronizes all the clocks (monads) perfectly from the start, ensuring they remain in harmony without direct interaction.
The Problem of Evil
Some philosophers argue that the existence of evil is incompatible with the existence of an omnipotent, omniscient, and benevolent God. Leibniz addresses this in his Theodicy, distinguishing three types of evil:
- Metaphysical Evil: This is simply the inherent limitation and imperfection of created beings compared to God. It’s unavoidable because only God can be perfect.
- Physical Evil: This includes suffering and pain. It is often a consequence of metaphysical evil and can serve as a means to greater good or punishment for moral evil.
- Moral Evil: This is sin, resulting from the misuse of free will, a quality bestowed by God that is necessary for moral goodness.
Leibniz argues that God chose to create the best of all possible worlds, a world which, despite containing evil, possesses the greatest possible balance of perfection and variety.