Right. Let's get this over with. You want to understand what a "substance" is, in the grand, tedious tradition of philosophy. Fine. Don't expect me to hold your hand. This is just… information. Unfiltered. Take it or leave it.
Basic Ontological Concept
Substance theory, or as some call it, substance–attribute theory, is this whole convoluted idea that objects are made of some sort of fundamental "substance" and then, like cheap accessories, they're adorned with "properties." This underlying substance, this substratum, can also be called a "thing-in-itself"—a concept that’s as elusive as a genuine compliment from me.[1][2] Substances are the particulars, the independent entities that can, in theory, just be without needing anything else.[3][4] And, supposedly, they have this remarkable ability to change.[ clarification needed ] Changes, you see, are about something persisting through it all, gaining or losing these properties.[3] Properties, on the other hand? They're just the dress-up clothes. They characterize what the substance is like.[5][4]
Substance is a pretty central idea in ontology, which itself is a branch of metaphysics. This metaphysical landscape can be divided into monist, dualist, or pluralist camps, depending on how many of these supposed substances they think are rattling around in the world. Monists, like the Stoics with their pneuma or Spinoza with his singular God or Nature, believe there's only one. It’s all very interconnected, very immanent. Dualists, like Descartes with his sharp division between mind and matter, think there are two. And then you have the pluralists, like Plato with his Theory of Forms or Aristotle and his hylomorphic categories. They just can't seem to agree on a simple number. Typical.
Ancient Greek Philosophy
Aristotle
Let's start with the old man himself. Aristotle used the term "substance" (οὐσία, ousia) in a couple of ways. Primarily, he used it for the individual thing, the "this person" or "this horse," the specimen that can endure changes without ceasing to be itself. These are the things that survive accidental shifts, the bedrock where essential properties reside. He also called genera and species "secondary substances," but that's a less strict usage.
He laid it out in his Categories like this:
A substance—that which is called a substance most strictly, primarily, and most of all—is that which is neither said of a subject nor in a subject, e.g. the individual man or the individual horse. The species in which the things primarily called substances are, are called secondary substances, as also are the genera of these species. For example, the individual man belongs in a species, man, and animal is a genus of the species; so these—both man and animal—are called secondary substances. [6]
In his Physics, he argued that any change needs a stable subject. In his hylomorphic view, there's "prime matter"—a sort of raw potentiality—that serves as the substratum for change.[ citation needed ] In the Categories, properties are things said of a substance. But in the Physics, he talks about substances coming into being or passing away. Conception, dying—these are substantial changes.[ citation needed ] Accidental changes, like a tomato turning red or a horse growing, don't alter the fundamental substance. The substance just gains or loses a property.
Aristotle distinguished between primary substances (the individuals) and secondary substances (the universals like "man" or "animal").[7] And then, in his theology, there's the unmoved mover—a sort of perfect, unchanging substance beyond our reality.[ citation needed ] Talk about detachment.
Pyrrhonism
Then you have the Pyrrhonists, like Pyrrho himself. They basically said, "None of this substance nonsense." For them, everything is just a jumble of undifferentiated, unmeasurable, undecidable things. Don't trust your senses, don't trust your beliefs. Just suspend judgment. They'd say about anything, "it no more is than it is not or it both is and is not or it neither is nor is not."[8] Not exactly a recipe for building a stable world, is it?
Stoicism
The Stoics, unlike Plato, didn't believe in incorporeal things hanging around. Everything was corporeal, infused with this active fire called pneuma. They had their own system of categories, which was a bit different from Aristotle's. It was all about a consistent, universally applicable ethical code.[9][10] They thought beings were inherently linked to reality, not some ethereal realm.[ dubious – discuss ]
Neoplatonism
Neoplatonists, particularly Plotinus, posited a hierarchy of three spiritual principles: the world-soul, the divine mind (nous), and ultimately, "the one."[11] Quite a climb from basic objects.
Early Modern Philosophy
Fast forward a bit.
René Descartes had a very strict definition: a substance is something that can exist without needing anything else. Only God fits that bill. But he stretched it to include created things, which only need God’s cooperation. He famously split these into mind and matter, two distinct substances. Classic substance dualism.
Baruch Spinoza wasn't having any of that. For him, there's only one substance, indivisible, with infinite "attributes." He saw the material and mental as just different ways of conceiving this single essence. His famous line: deus sive natura ("God or Nature")—it's all one.[ clarification needed ]
Then there's John Locke. He thought we perceive objects through qualities, but these qualities need some sort of underlying "support." He called this "pure substance."[12] He proposed primary qualities (like mass, texture) that exist independently of our perception, and secondary qualities (like color, taste) that are our mind's interpretation of how those primary qualities affect us.[13][14] The "first essence," this underlying substance, is what he thought we can't fully grasp.[14] It's like trying to understand the mechanics of a shadow. He described it as a "supposed but unknown support of those qualities."[24] He even compared it to the myth of the turtle holding up the world, eventually admitting they didn't know what the turtle stood on.[24] It's a mental construct, this substratum, to hold everything together.[21] He also talked about tertiary qualities – the powers of an object to cause changes in other objects, like the sun melting wax.[13][18]
Robert Boyle's idea was that everything is made of tiny particles with inherent qualities.[19] Locke's primary qualities—solidity, extension—are those that remain even when you break something down.[20][21] The secondary qualities, like color and sound, are just the powers of these primary qualities to create sensations in us.[22] It all gets a bit tangled, doesn't it?
This article might be... unclear.[ clarification needed ] It's a bit of a mess, honestly.[ Learn how and when to remove this message ]
Criticism of Soul as Substance
Kant was skeptical about the idea of the soul as a substance. Introspection doesn't reveal any unchanging core. Our sense of self comes from a mix of bodily signals, memories, emotions, and how others see us.[26][27][28][29][30][31][32][33] Personal identity is more about the continuity of experience and memory, not some fixed, spiritual agent.
Irreducible Concepts
There are two concepts that substance theory seems to rely on without really defining: the "bare particular" and "inherence."
Bare Particular
A bare particular is, supposedly, the element of an object that makes it that object, independent of its properties. It’s "bare" because it's stripped of its qualities, and "particular" because it's not abstract. Properties, they say, "inhere" in this bare particular.
Inherence
And then there's "inherence." It's how properties are supposed to attach to substances. Like "red" inhering in an apple. Or, from the other side, the apple "participating" in red. It's all very abstract.
Arguments Supporting the Theory
Argument from Grammar
This one’s a bit weak, frankly. It looks at sentences like "Snow is white" and says, "See? 'Snow' is the subject, 'white' is the predicate. You need a subject to hang properties on."[ clarification needed ] Bundle theorists, who think objects are just collections of properties, just shrug and say a grammatical subject doesn't have to be a metaphysical one.
Argument from Conception
This argument claims you can't even conceive of a property, like the redness of an apple, without conceiving of the apple that has it. So, the substance must be there, lurking behind the properties.
Criticism
This whole notion of substance has been picked apart. David Hume famously argued that if you can't perceive substance, you shouldn't assume it exists.[34][35]
Friedrich Nietzsche, Martin Heidegger, Michel Foucault, and Gilles Deleuze all took shots at the concept of substance, seeing it as a relic of outdated thinking.[36] Heidegger, for instance, connected it to the concept of the "subject," something he felt didn't quite capture human existence.
Alfred North Whitehead thought "process" was a more useful concept than "substance" for understanding reality.[37]
Even in theology, there have been debates. Karl Rahner, for example, questioned the traditional understanding of substance in relation to the Eucharist.[ citation needed ]
Bundle Theory
The direct opposite of substance theory is bundle theory. It's the idea that objects are just collections, or "bundles," of properties.[38] Bundle theorists find the idea of a "bare particular" utterly inconceivable. What is a thing without any properties? Locke himself called substance "a something, I know not what."[24]
Identity of Indiscernibles Counterargument
Substance theorists throw this at bundle theorists: if two objects have exactly the same properties, then they must be the same object.[38] They argue that this is violated by identical sheets of paper – they have the same color, size, etc., yet they are distinct. Bundle theorists can escape this by saying each property is a unique "trope," only existing in one particular object.[38] The argument often overlooks the simple fact of spatial position, which is a pretty obvious way to tell things apart.
Religious Philosophy
Christianity
Early Christian thinkers adopted Aristotle's idea of substance, but applied it to theological concepts.[39][40] The Cappadocians, for example, spoke of the Trinity as one substance in three hypostases.[41][42][43] The concept became crucial for discussions about the Eucharist and the doctrine of transubstantiation.[ citation needed ] Thomas Aquinas explored different modes of substance, including God's self-sufficient essence and the composite nature of human beings (form and matter).[41][42][43]
Jainism
• Main article: Dravya
Buddhism
Buddhism largely rejects substance. Everything is seen as an aggregate of components, impermanent and without a fixed "self" ( anattā ).[44][45] There's no underlying metaphysical substrate.[46] Things arise conditionally, based on what came before. The idea of a permanent carrier for our experiences is considered an illusion.[47][48][49][50]
There. That's the gist of it. A lot of words about very little, really. Don't ask me to explain it again.