This question asks how much plurality belongs at the most basic level of reality. Spinoza admits one self-sufficient substance, God or Nature, with finite things as its modes. Cartesian substance dualism admits thinking and extended substances as two irreducible kinds. Leibniz instead makes the world rest on infinitely many simple, unextended substances, or monads.
Metaphysics
How Many Fundamental Substances?
Does reality consist fundamentally of one substance, two fundamentally different kinds of substance, or many substances?
Positions
- Leibnizian Substance Pluralism
Reality contains infinitely many simple, unextended substances—monads—and bodies are grounded in them rather than being substances of a second material kind.
- Spinozistic Substance Monism
Exactly one substance exists: God or Nature; every finite thing is a mode of that substance.
Held by Spinozism
- Substance Dualism
Mind and body are fundamentally distinct substances, and the mind is not reducible to the physical body.
On this question, substance dualism counts two fundamental kinds of created substance—thinking minds and extended bodies—rather than only two individual substances.
Engaged by schools of thought
- Atomism
Leucippus and Democritus answered with two: indivisible atoms of one kind of matter, and the void in which they move; everything else is their arrangement.
- Milesians
Thales, Anaximander, and Anaximenes each proposed one originating stuff, water, the boundless, or air, from which everything else arises: the earliest answers to how many basic substances there are, and the answer is one.
- Pluralists
Empedocles answered Parmenides with four permanent roots, earth, water, air, and fire, mixed and parted by Love and Strife, and Anaxagoras with unlimited seeds of every kind ordered by Mind: many basic substances, none of which comes to be or perishes.
- Pythagoreanism
The fifth-century Pythagoreans, above all Philolaus, held that things are constituted from limiters and unlimiteds bound together by number, so that number and structure rather than any material stuff are what is basic.