Substance What
A longtime reader with the latinate yet indecipherable name of Nostreculsus (and with the truly awesome icon of a chinaman who eats with sticks once seen on Mulberry Street, but no longer) writes and asks:
At the grave risk of revealing my appalling ignorance and the ignorance of my fellow moderns, I confess that I was lost on reading the very first sentence. Namely, I don’t understand what is this “substance” of which you speak.
Naturally, I tried looking up the word. Wikipedia writes “Substance theory, or substance–attribute theory, is an ontological theory positing that objects are constituted each by a substance and properties borne by the substance but distinct from it” and goes on from there to describe theories of one, two or many substances.
Physics nowadays dispenses entirely with the concept, unless it is expressed by another word. Is “substance” the same as the state of a system and “properties” another word for observables?
The answer is no. “Substance” as the term in used in ontology, is not “the state of a system” as that phrase is used in that branch of natural philosophy called physics, nor is the term “properties” in ontology another word for “observables” in physics. The concepts are quite different.
And you venture no risk. A call to define one’s terms is always in order.
The term “substance” in philosophy is a term of art. It hardly a matter of ignorance, and certainly not an appalling ignorance, not to know a technical term from a field in which one is not trained. Please voice no qualms for asking a question: I love questions.
The Wikipedia definition is correct as it stands, if worded elliptically.
The philosophical term ‘substance’ corresponds to the Greek ousia, which means ‘being’, or in Latin substantia, which literally means ‘foundation’ or ‘what stands beneath.’ The branch of philosophy examining claims about substances is called ‘ontology.’
A ‘substance’ is the foundation or fundamental being of reality. It is the thing that cannot be reduced to a simpler thing.
‘Properties’ are particulars about the thing, which can be reduced to simpler things.
Thus, for Lucretius, a Greco-Roman atomist, atoms are the substances. Atoms make up all things, but are themselves not made up of anything more fundamental. They are the foundation.
For Hume, a radical empiricist, impressions and ideas are the substances: impressions are the ground of being, and cannot be further analyzed, nor further resolved, into parts.
For Plato, a Platonist, everything derives its existence from a Form or an Idea (eidos); in this terminology, Plato’s ‘substance’ would be the ‘forms’ from which all material things participate, and from which they derive their being.
Aristotle’s conclusion was opposite, taking the matter as primary, and ideas about matter as abstractions deduced or derived from them, hence secondary, hence not a substance.
Plato argued, for examples, that all dogs of any breed seen in the visible world are “dogs” because each participates in the one form or idea of Dog, that is, dogness, which is not seen but known, and that this formal oneness is primary.
Aristotle argued that the idea of Dog is an abstraction in the mental world built up out of many particular sights in the visible world, and that the multitude is primary. This the what philosophers for millennia have called the question of ‘The One and the Many.”
Descartes argument is that mind and matter are both substances, since neither can be resolved into anything more fundamental, and neither can be resolved into each other.
Scholastic thinking, based on Aquinas, held that the human soul is the substantial form of the human body, that is, what gives it life and defines its being. Aquinas holds that the soul is responsible for all the various human capacities — nutrition, reproduction, growth, sensation, appetite, locomotion, intellect, and volition. Likewise the way the souls of plants and beast are responsible for their capacities. Plants lack locomotion, beasts lack intellect and volition. But Aquinas is concludes purely intellectual capacities cannot have a corporeal organ: he concludes that the soul carries out immaterial operations alongside its corporeal ones.
Hence, in this terminology, the human soul is the substance, and the mental and physical activities and properties are manifestations derived from it.
In this matter, as in all matters, I myself follow the scholastic school.
For the record, physics does not and cannot “dispense” entirely with the concept of substance, any more than the “broken window” theory of policing can “dispense” with “stare decisis” — for stare decisis is a juristic concept about which various theories of policework have no say. Law, which is the topic of legal theory, is what gives police their authority, and policework cannot exist outside of the law.
Likewise here. Natural philosophy is a branch of philosophy. Physics is the branch of natural philosophy concerned with the empirical study of the observable properties of matter. The discipline of physics depends on the ontological axiom that matter is a substance.
Physics makes no comment, nor can it make any comment, about any non-empirical substances, if any, nor the relation of matter to them.
Physics cannot ‘dispense’ with materialism any more than it can dispense with mathematics or with cause and effect: these are ontological, epistemological, and metaphysical assumptions forming the foundation on which physics stands.
About John C Wright
John C. Wright is a practicing philosopher, a retired attorney, newspaperman, and newspaper editor, and a published author of science fiction. Once a Houyhnhnm, he was expelled from the august ranks of purely rational beings when he fell in love; but retains an honorary title.
