A categoricalist claims that solubility (a disposition) is grounded in molecular structure (a categorical property). What does this grounding claim mean?
ASolubility and molecular structure are identical properties described in different ways
BThe molecular structure is what makes the object soluble — the disposition exists because of how the object categorically is, and would not exist otherwise
CDispositions cause categorical properties to come into being when triggered
DCategorical properties are more directly observable than dispositions
Grounding is an explanatory, asymmetric relation: the categorical property explains why the disposition exists, not vice versa. Solubility (what a substance would do if placed in water) is grounded in molecular structure (how the atoms are actually arranged) in the sense that the molecular arrangement is the real basis for the disposition. Change the structure, and the solubility changes; the structure is explanatorily prior. This is not identity: 'soluble' and 'has such-and-such molecular structure' are different concepts even if one grounds the other.
Question 2 Multiple Choice
A pure dispositionalist argues that mass — typically cited as a paradigm categorical property — is actually dispositional. What is their strongest argument?
AMass cannot be directly measured or observed
BMass is entirely defined by its role in gravitational and inertial relations — how objects with mass behave — so it has no intrinsic nature independent of those causal roles
CMass is a macroscopic property that reduces to more fundamental categorical properties at the quantum level
DCategorical properties only exist at the scale of everyday objects, not fundamental physics
The dispositionalist's best move is to argue that what we call 'categorical' properties are really just dispositions that are never manifested, or properties fully characterized by their causal roles. Mass is defined by Newton's second law (F = ma) and the law of universal gravitation — both relational, dispositional characterizations. If mass just *is* the property that plays these roles, then categoricalism about mass is an illusion: there is no 'intrinsic nature' of mass over and above its behavioral role. This is the deepest challenge to categoricalism.
Question 3 True / False
Categorical properties characterize what a thing intrinsically is right now, independently of any conditional claims about how it would behave under various circumstances.
TTrue
FFalse
Answer: True
This is the defining feature of categorical properties. Unlike dispositions (fragility, solubility, conductivity) which are characterized by what an object *would do* if conditions were met, categorical properties are purely occurrent: the shape of a crystal, the spatial arrangement of atoms, the charge distribution in a molecule. These are features of how things are, not what they would do. The categorical/dispositional distinction tracks the difference between occurrent features and modal (would-be) features.
Question 4 True / False
The debate between categoricalism and pure dispositionalism is merely semantic — both views make the same predictions about the physical world and agree on most substantive questions.
TTrue
FFalse
Answer: False
This is a substantive metaphysical dispute with real consequences. Categoricalism implies that properties have intrinsic natures that are logically independent of their causal roles — the same categorical basis could, in principle, give rise to different dispositions in different possible worlds. Pure dispositionalism implies that properties are exhausted by their causal roles — there is nothing to a property beyond what it does. These views differ on the nature of laws of nature, the analysis of counterfactuals, and the structure of modality.
Question 5 Short Answer
Why do categoricalists say categorical properties are the 'bedrock' of reality, and what challenge does the pure dispositionalist pose to this picture?
Think about your answer, then reveal below.
Model answer: Categoricalists say categorical properties are bedrock because all dispositions must ultimately be grounded in something non-dispositional — otherwise you get an infinite regress of 'would-do X if Y, where Y would occur if Z...' with nothing to stop it. Categorical properties are self-standing: they just are what they are. The dispositionalist challenges this by arguing that even paradigm categorical properties like mass or charge are fully characterized by their causal roles, meaning the regress never bottoms out in something truly non-dispositional.
The regress argument is the categoricalist's main motivation: if every property is defined by what it would do, and what it would do is defined by further properties, which are in turn defined by what they would do, then nothing has any determinate nature — reality becomes an empty web of mutual conditionals. Categorical properties provide a grounding point. The dispositionalist response is that this regress is not vicious: mutual characterization among properties is coherent, and the world can be a self-supporting web of dispositions without needing a non-dispositional foundation.