Substance Monism

Substance Monism is the metaphysical doctrine, defended most rigorously by Baruch Spinoza in the Ethics (1677), that there is one and only one substance. The single substance is infinite, self-caused, and identifiable as both God and Nature (Spinoza's Deus sive Natura, God or Nature); everything else — minds, bodies, individual things — is a mode of this single substance rather than a substance in its own right.

The doctrine is one of the most radical in the history of Western metaphysics. Spinoza's contemporaries widely judged it atheistic or pantheistic and dangerous; later receivers (especially in the German Romantic and Idealist traditions) treated it as one of the major philosophical achievements of the modern era. The doctrine has been continuously contested and continuously productive.

Definition

The doctrine has two principal claims. First, there is exactly one substance — the infinite, necessary, self-caused being that exists in itself and is conceived through itself. Second, what we ordinarily take to be substances in their own right (individual humans, animals, plants, physical objects) are not in fact substances; they are modes — modifications or affections of the one substance, having their being in and through it rather than independently.

Origin

The doctrine emerges with Spinoza in the Ethics, published posthumously in 1677. The argumentative route by which Spinoza arrives at substance monism is a deliberate radicalization of the Cartesian framework. Descartes had defined substance as that which exists in such a way that it depends on nothing else for its existence. By this strict definition, Descartes argued, only God is properly substance; finite things (minds and bodies) are substances in a derivative sense. Spinoza accepts the definition but presses its consequences: if substance is what depends on nothing else, there can be only one substance, since two substances each depending on nothing else would limit each other (each is what it is by being distinct from the other) in ways that would compromise the independence each requires.

The core claim

The core claim has three parts.

There is exactly one substance. The arguments of Ethics I, Propositions 1–15, establish through systematic deduction that exactly one substance exists. The proofs proceed from Spinoza's definitions and axioms through a sequence of intermediate propositions to the conclusion that two substances with the same attributes would be indistinguishable, two substances with different attributes could share no common nature and could not limit each other, and therefore exactly one substance exists.

The one substance is identifiable as God or Nature. Spinoza uses both names. God names the substance considered as infinite and self-caused; Nature names the same substance considered as the totality of what is. The famous formulation Deus sive Natura (God, or Nature) marks the identification.

Everything else is a mode of the one substance. Individual things (minds, bodies, plants, animals, objects) are not substances in their own right; they are modes — finite, particular modifications of the one infinite substance. The relation of mode to substance is one of in-being and conception-through: modes are in the substance and are conceived through the substance, not in or through themselves.

The consequences

The doctrine has substantial consequences across Spinoza's system.

The mind-body problem dissolves. Mind and body are not two distinct substances (as Descartes had held); they are the same single substance expressed under two different attributes (thought and extension). The famous Spinozist parallelism — every mode of thought has a corresponding mode of extension and vice versa — follows from the recognition that mind and body are aspects of the same underlying reality, not separate things.

Free will in the libertarian sense is impossible. Modes are not substances; they have no independent power of action. Every mode (including every human action) follows necessarily from the nature of substance through the chain of causes. Human freedom, on Spinoza's redefinition, consists not in escape from causal determination (which is impossible) but in understanding the causes that determine one's actions — acting from one's own nature rather than being externally compelled.

The intellectual love of God is the highest human achievement. When the human mind adequately understands the nature of substance and grasps that everything (including itself) follows necessarily from that nature, the mind achieves what Spinoza calls the intellectual love of God — a contemplative-affective state that is simultaneously the mind's love of substance and (because there is only one substance, of which the mind is a mode) substance's love of itself.

Reception

The contemporary reception of substance monism was almost uniformly hostile. The doctrine was treated as pantheism or atheism (Spinoza was widely accused of both); the German philosopher F.H. Jacobi's late-eighteenth-century Pantheismusstreit (Pantheism Controversy) revived the question of whether substance monism was an acceptable philosophical position or a dangerous departure from theistic orthodoxy.

The German Idealist tradition substantially recovered Spinoza. Goethe described Spinoza as one of his three great teachers; Schelling and Hegel developed forms of monism that owed substantial debts to Spinoza; Einstein in the twentieth century explicitly endorsed Spinoza's God. The contemporary scholarly recovery has been substantial, especially through the work of Edwin Curley, Michael Della Rocca, Steven Nadler, and many others.

Common confusions

Substance monism is not the same as material monism. Material monism is the doctrine that everything is material; Spinoza's substance monism is consistent with the existence of mental modes (modes of thought) alongside physical modes (modes of extension). The single substance has infinitely many attributes, of which the human mind knows two (thought and extension); mind and matter are both real, both modes of the same single substance.

Substance monism is not the same as pantheism in the conventional sense. Pantheism in popular usage often suggests that nature is divine in a sentimental or worshipful way. Spinoza's identification of God and Nature is more technical: the single substance has the properties that classical theism attributed to God (infinite, eternal, self-caused, the source of all being) but does not have other properties (personhood, providential care, distinct existence over and above the natural order) that classical theism also attributed to God.

Substance monism does not deny the reality of individual things. Spinoza is not claiming that you and the chair you are sitting on do not exist; he is claiming that you and the chair are not substances in the strict metaphysical sense — you are modes of the single substance, finite modifications that exist in and through it.

Place in the wiki

Substance Monism is a satellite of the Pillar concept Substance, representing one of the major historical positions on the metaphysical category. It is closely related to the Principle of Sufficient Reason (which Spinoza's monism deploys in its strongest form) and to Free Will (which the monism rules out in the libertarian sense).

Further reading

• Spinoza — the author of the doctrine
• Rationalism — the tradition
• Substance — the broader metaphysical category
• Descartes — the philosopher whose substance definition Spinoza radicalized
• Hegel — the major later receiver who developed his own form of monism
• Principle of Sufficient Reason — the methodological principle that drives Spinoza's monism

Satellite of Substance. The most radical historical position on the unity of substance.