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Let's discuss the idea that there are no such things as properties, just lots of things which are more or less similar

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Let's discuss the idea that there are no such things as properties, just lots of things which are more or less similar

Then AI response

The Ontological Minimalist: Resemblance Nominalism

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How do two distinct physical objects—such as a ripe tomato and a stop sign—share the exact same feature, such as being "red"? In metaphysics, the standard *realist* response posits the existence of **universals**: abstract, repeatable entities that exist over and above individual things and are instantiated by them. The thesis you have introduced is the core commitment of **Resemblance Nominalism**, an elegant alternative within *nominalism* (the denial of abstract entities). It claims that the fundamental furniture of the world consists solely of concrete particulars; properties do not exist as independent metaphysical items. Instead, an object is "red" simply because it resembles a set of other concrete, red objects. ``` THE METAPHYSICAL DIVIDE REALISM RESEMBLE NOMINALISM (Universals exist) (Only particulars exist) [ Universal ] [ Object A ] / \ \ resembles [ Object A ] [ Object B ] [ Object B ] ``` ### Mechanisms and Logical Architecture To understand how this operates, consider how a resemblance nominalist constructs what we ordinary speakers call "properties": 1. **Primitive Resemblance:** Resemblance is treated as an irreducible, primitive relation. Objects do not resemble one another *because* they share a property; rather, we say they share a property *because* they resemble one another. 2. **Equivalence Classes:** A "property" is reinterpreted as a maximal group of particulars that resemble each other to a requisite degree. 3. **Paretian / Paradigm Models:** Some versions select paradigm instances (e.g., a standard reference meter or a ideal sample of red) and define membership in a property class by an object’s degree of similarity to those paradigms. ### The Core Debates: Russell’s Regress and Coextension Despite its intuitive appeal, Resemblance Nominalism faces two classical objections in analytic metaphysics: * **Russell’s Regress:** Formulated by Bertrand Russell in *The Problems of Philosophy* (1912), this argument asserts that if you eliminate properties by invoking a relation of *resemblance*, you must explain what all individual acts of resemblance have in common. They must resemble each other, requiring a higher-order resemblance relation, triggering an infinite regress. Russell argued this proves that at least *one* universal—the relation of resemblance itself—must exist. Modern nominalists, such as Gonzalo Rodriguez-Pereyra, counter that resemblance is a multigrade relation that applies directly to particulars without constituting a repeatable universal. * **The Problem of Coextensive Properties:** If two distinct properties belong to the exact same set of objects in the actual world (for example, *renate* [having kidneys] and *cordate* [having a heart]), resemblance nominalism risks treating them as identical because the set of resembling objects is identical. Resolving this often forces nominalists to extend their scope to *possible* objects across modal space, importing heavy cosmological commitments to preserve a lean ontology. ### Broad Implications Resemblance Nominalism aligns closely with cognitive science theories of categorization, such as **prototype theory**, where human concepts are structured around similarity to central exemplars rather than strict, necessary-and-sufficient features. Economically, it offers a sparse ontology—reducing the universe to concrete entities and their concrete relationships—though critics argue that it merely sweeps metaphysical complexity under the rug of "primitive similarity". ## Follow-up questions 1. How does resemblance nominalism handle cases where two distinct properties happen to be possessed by the exact same set of objects? 2. Does Bertrand Russell’s regress argument successfully force the resemblance nominalist to accept at least one universal? 3. How do modern prototype theories in cognitive psychology mirror or challenge the philosophical assumptions of resemblance nominalism?

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Then Question · @MayaDarmon

What are the main motivations for property nominalism?

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Then AI response

Motivations for Property Nominalism

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While the denial of universals is often framed as mere ontological thrift, the deepest motivations for property nominalism extend far beyond basic parsimony. They stem from profound epistemological, causal, and semantic pressures that challenge the coherence of realist metaphysics. ``` MOTIVATIONS FOR PROPERTY NOMINALISM EPISTEMIC ACCESSIBILITY CAUSAL CLOSURE (How can we know abstracta?) (Abstract objects cannot act) \ / \ / v v [ NOMINALIST ONTOLOGICAL FRAMEWORK ] | v NATURALISTIC ADEQUACY (Eliminates abstract mystery) ``` ### The Epistemic and Causal Imperatives The primary driver for nominalism is the **Epistemic Access Problem**, famously articulated by Paul Benacerraf against mathematical platonism and adapted widely across metaphysics. If universals are non-spatiotemporal, abstract entities, they lack causal efficacy. How, then, can physical organisms operating within a spatiotemporal realm interact with or acquire knowledge of them? Realism creates an unbridgeable explanatory gap between the abstract realm of properties and human cognitive mechanisms. Nominalism resolves this by anchoring all truth-makers in concrete, epistemically accessible particulars. Closely tied to this is the principle of **Causal Closure** in physicalism: only entities capable of entering into causal networks are explanatory. Abstract universals do no work in empirical science. A physician diagnoses a condition based on concrete cellular structures and biochemical cascades, not by appealing to an abstract "disease universal." By refusing to multiply entities beyond necessity—a strict application of *Ockham's Razor*—nominalism keeps ontology aligned with naturalistic science. ### The Semantic and Mereological Puzzles of Realism Nominalism is also motivated by internal paradoxes within realist frameworks, particularly regarding instantiation: * **The Problem of Spatial Location:** Realists must claim that a single universal (e.g., "whiteness") is fully present in a snowflake in Canada and a swan in Australia simultaneously. Nominalists argue that this violates fundamental mereological intuitions—the principle that an entity cannot be wholly present in two disjoint spatial locations at once. * **Bradley's Regress:** Formulated by F.H. Bradley, if an object $a$ instantiates a universal $F$, there must be a tie or relation of *instantiation* holding them together. But if instantiation is itself a relational universal, it requires a higher-order relation to connect it to $a$ and $F$, triggering a vicious infinite regress. Nominalism avoids this by refusing to treat instantiation as an extra entity in the universe. By grounding state-affairs entirely in concrete particulars, nominalism preserves a unified, naturalistic worldview free from abstract, causally inert entities.
Then Related Ideas · AI

1. Historical or Intellectual Foundation: Medieval Constitutive Ontologies

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``` MEDIEVAL & EARLY MODERN DEBATE / \ REALIST EXTRA-ENTITY HYPOTHESIS NON-RELATIONAL/CONSTITUTIVE (Requires higher-order ties) (Duns Scotus's *haecceity* / Triggering: Infinite Regress Suárez's *fundamental modes*) \ / v v [ FORMALIZATION BY F.H. BRADLEY ] *Appearance and Reality* (1893) ``` **Context & Connection:** Long before F.H. Bradley formulated his regress in *Appearance and Reality* (1893), late medieval Scholastics—most notably Duns Scotus and Francisco Suárez—grappled with the *problem of unity*: how a nature (universal) and a particularizing feature combine without generating an endless chain of intermediate entities. Scholastics recognized that if the unifying principle is treated as a distinct "thing" (*res*), it demands its own unifier. Scotus answered this with the concept of the **haecceity** (*thisness*), an ultimate reality that individuates a nature without acting as a separate relation. Suárez later argued that properties adhere to subjects via **inherence modes**—aspects of reality that do not possess independent existence and thus do not require further relations to attach them. **Insight / Question:** Examining Bradley's regress through this scholastic debate reveals that the regress is not merely a modern weapon for nominalists; it is a structural challenge for *any* constituent ontology. It raises the core question: *Can two distinct entities be unified by something that is not itself an entity, or does any non-relational tie ultimately collapse into a mere verbal trick?* --- ### 2. Empirical or Scientific Connection: Quantum Entanglement and Non-Relational Holism ``` MACROSCOPIC ONTOLOGY QUANTUM MECHANICS [ Object A ] [ Object B ] [ Entangled State |Ψ⟩ ] \ / | (Relation R) v | Non-Relational Holism v (No relational "tie" needed; Bradley's Regress system is unified) ``` **Context & Connection:** Classical ontologies model systems by identifying discrete objects and posits (e.g., spatial or causal relations) that bind them, exposing them to Bradley-style regresses. Quantum mechanics, however, offers an empirical countermodel in the form of **quantum entanglement**. In an entangled system (such as two spin-singlet electrons), the physical properties of the composite system $|\Psi\rangle$ cannot be decomposed into the intrinsic properties of particle $A$, particle $B$, and a fundamental physical "relation" holding between them. Quantum state holism suggests that the system's unity is fundamental rather than relationally constructed. **Insight / Question:** Empirical phenomena like entanglement challenge the assumption that unity requires a relational glue. This suggests a testable philosophical question for physicalism: *Does quantum mechanics provide an empirical instance of non-relational instantiation, demonstrating that subatomic reality avoids Bradley's regress by realizing states of affairs that cannot be reduced to relata plus relations?* --- ### 3. Opposing Framework: Non-Relational Tie and Primitive Exemplification ``` REALIST RESPONSES TO BRADLEY / \ PRIMITIVE EXEMPLIFICATION TROPE ONTOLOGY (D.M. Armstrong) (Keith Campbell) - Instantiation is a "non-relational - Particularized natures tie" or state of affairs. - Self-unifying; no universal - Relata are unmediated. or relation required. ``` **Context & Connection:** Realistic metaphysics does not yield to Bradley's regress automatically. A major counter-framework—defended by Armstrong in *Universals and Scientific Realism* (1978)—argues that Bradley’s argument rests on a category mistake: treating **instantiation** (or exemplification) as if it were a standard relational universal. Armstrong posits that instantiation is a **non-relational tie** or a primitive state of affairs. On this view, an object $a$ having property $F$ is a single, irreducible *state of affairs* rather than three separate items ($a$, $F$, and $R$) tied together. Alternatively, **Trope Theory** solves the problem by rejecting universals entirely; tropes are particularized qualities (like *the specific redness of this apple*) that are self-instantiating, eliminating the need for an instantiation tie altogether. **Insight / Question:** Confronting Nominalism with primitive realism reframes Bradley's regress from a definitive debunking of universals into a debate about primitive concepts. It asks: *Is primitive instantiation an ad hoc defense to stop a regress, or is it an indispensable feature of any coherent theory of state-of-affairs structure?* --- ### 4. Cross-Disciplinary or Practical Direction: Type Theory and Graph Data Architectures ``` COMPUTER SCIENCE & LOGIC Type Theory Graph Databases (Russell & Whitehead) (RDF / Knowledge Graphs) | | Prevents Type Collisions Avoids Infinite Triples (Properties cannot take (Nodes & edges are defined themselves as arguments) without reifying edges indefinitely) ``` **Context & Connection:** The structural logic of Bradley's regress appears directly in theoretical computer science, database design, and knowledge representation. * **Type Theory:** In formal logic, Bertrand Russell developed the *Theory of Types* (partly in response to regress and paradoxes), dictating that a predicate/property belongs to a higher type than the object it modifies. An instantiation relation cannot be of the same type as the relations it unifies, structurally blocking infinite regresses of the Bradley type. * **Graph Databases:** In semantic web architectures (e.g., Resource Description Framework or RDF), data is represented as triples: `(Subject, Predicate, Object)`. If a system attempts to represent the *validity* or *meta-properties* of a edge/predicate by treating every edge as a node that requires a new edge, it encounters a system-crashing regress known as **infinite reification**. Practical computer science avoids this by treating edges as native primitive structural bindings rather than data entities. **Insight / Question:** Computer science demonstrates that nominalist and realist strategies for solving Bradley's regress have practical computational constraints. It raises the applied question: *How do choices between primitive structural links (Realist "ties") and pure node-attribute clustering (Nominalism) affect the scalability and semantic expressiveness of formal knowledge representation algorithms?*

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