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Single Idea 18392

[filed under theme 6. Mathematics / A. Nature of Mathematics / 4. Using Numbers / a. Units ]

Full Idea

Classes, because they have a particular cardinality, are essentially a certain number of ones, things that, within the particular class, are each taken as a unit.

Gist of Idea

Classes have cardinalities, so their members must all be treated as units

Source

David M. Armstrong (Truth and Truthmakers [2004], 09.1)

Book Ref

Armstrong,D.M.: 'Truth and Truthmakers' [CUP 2004], p.114


A Reaction

[Singletons are exceptions] So units are basic to set theory, which is the foundations of technical analytic philosophy (as well as, for many, of mathematics). If you can't treat something as a unit, it won't go into set theory. Vagueness...

Related Idea

Idea 18396 The set theory brackets { } assert that the member is a unit [Armstrong]


The 133 ideas from David M. Armstrong

Refusal to explain why different tokens are of the same type is to be an ostrich [Armstrong]
Particulars and properties are distinguishable, but too close to speak of a relation [Armstrong]
Some think of reality as made of things; I prefer facts or states of affairs [Armstrong]
Maybe experience is not essential to perception, but only to the causing of beliefs [Armstrong, by Scruton]
Externalism says knowledge involves a natural relation between the belief state and what makes it true [Armstrong]
All possibilities are recombinations of properties in the actual world [Armstrong, by Lewis]
Negative existentials have 'totality facts' as truthmakers [Armstrong, by Lewis]
A mental state without belief refutes self-intimation; a belief with no state refutes infallibility [Armstrong, by Shoemaker]
If pains are defined causally, and research shows that the causal role is physical, then pains are physical [Armstrong, by Lycan]
Armstrong and Lewis see functionalism as an identity of the function and its realiser [Armstrong, by Heil]
Armstrong suggests secondary qualities are blurred primary qualities [Armstrong, by Robinson,H]
To be realists about dispositions, we can only discuss them through their categorical basis [Armstrong]
The best version of reductionist actualism around is Armstrong's combinatorial account [Armstrong, by Read]
The problem of universals is how many particulars can all be of the same 'type' [Armstrong]
Causal Functionalism says mental states are apt for producing behaviour [Armstrong]
One mental role might be filled by a variety of physical types [Armstrong]
Behaviourism is false, but mind is definable as the cause of behaviour [Armstrong]
The identity of mental states with physical properties is contingent, because the laws of nature are contingent [Armstrong]
The manifestations of a disposition need never actually exist [Armstrong]
Consciousness and experience of qualities are not the same [Armstrong]
A causal theory of mentality would be improved by a teleological element [Armstrong]
Secondary qualities are microscopic primary qualities of physical things [Armstrong]
How can essences generate the right powers to vary with distance between objects? [Armstrong]
What matters is not how many entities we postulate, but how many kinds of entities [Armstrong, by Mellor/Oliver]
Deniers of properties and relations rely on either predicates or on classes [Armstrong]
Resemblances must be in certain 'respects', and they seem awfully like properties [Armstrong]
Whether we apply 'cold' or 'hot' to an object is quite separate from its change of temperature [Armstrong]
To the claim that every predicate has a property, start by eliminating failure of application of predicate [Armstrong]
Predicates need ontological correlates to ensure that they apply [Armstrong]
There must be some explanation of why certain predicates are applicable to certain objects [Armstrong]
Change of temperature in objects is quite independent of the predicates 'hot' and 'cold' [Armstrong]
We want to know what constituents of objects are grounds for the application of predicates [Armstrong]
In most sets there is no property common to all the members [Armstrong]
The introduction of sparse properties avoids the regularity theory's problem with 'grue' [Armstrong]
Regularities theories are poor on causal connections, counterfactuals and probability [Armstrong]
Tropes fall into classes, because exact similarity is symmetrical and transitive [Armstrong]
Trope theory needs extra commitments, to symmetry and non-transitivity, unless resemblance is exact [Armstrong]
Universals are required to give a satisfactory account of the laws of nature [Armstrong]
Without properties we would be unable to express the laws of nature [Armstrong]
Essences might support Resemblance Nominalism, but they are too coarse and ill-defined [Armstrong]
Even if all properties are categorical, they may be denoted by dispositional predicates [Armstrong, by Bird]
Properties are universals, which are always instantiated [Armstrong, by Heil]
Universals explain resemblance and causal power [Armstrong, by Oliver]
If what is actual might have been impossible, we need S4 modal logic [Armstrong, by Lewis]
A thing's self-identity can't be a universal, since we can know it a priori [Armstrong, by Oliver]
It doesn't follow that because there is a predicate there must therefore exist a property [Armstrong]
The type-token distinction is the universal-particular distinction [Armstrong, by Hodes]
Truth-making can't be entailment, because truthmakers are portions of reality [Armstrong]
Armstrong says truthmakers necessitate their truth, where 'necessitate' is a primitive relation [Armstrong, by MacBride]
For all being, there is a potential proposition which expresses its existence and nature [Armstrong]
A realm of abstract propositions is causally inert, so has no explanatory value [Armstrong]
The class of similar things is much too big a truthmaker for the feature of a particular [Armstrong]
We need properties, as minimal truthmakers for the truths about objects [Armstrong]
If tropes are non-transferable, then they necessarily belong to their particular substance [Armstrong]
Truthmaking needs states of affairs, to unite particulars with tropes or universals. [Armstrong]
General truths are a type of negative truth, saying there are no more ravens than black ones [Armstrong]
Negative truths have as truthmakers all states of affairs relevant to the truth [Armstrong]
Length is a 'determinable' property, and one mile is one its 'determinates' [Armstrong]
The determinates of a determinable must be incompatible with each other [Armstrong]
Negative causations supervene on positive causations plus their laws? [Armstrong]
Necessitating general truthmakers must also specify their limits [Armstrong]
The nature of arctic animals is truthmaker for the absence of penguins there [Armstrong]
One truthmaker will do for a contingent truth and for its contradictory [Armstrong]
Logical atomism builds on the simple properties, but are they the only possible properties? [Armstrong]
What is the truthmaker for 'it is possible that there could have been nothing'? [Armstrong]
The truthmakers for possible unicorns are the elements in their combination [Armstrong]
Possible worlds don't fix necessities; intrinsic necessities imply the extension in worlds [Armstrong]
When entities contain entities, or overlap with them, there is 'partial' identity [Armstrong]
All metaphysical discussion should be guided by a quest for truthmakers [Armstrong]
For 'there is a class with no members' we don't need the null set as truthmaker [Armstrong]
Classes have cardinalities, so their members must all be treated as units [Armstrong]
'Naturalism' says only the world of space-time exists [Armstrong]
In mathematics, truthmakers are possible instantiations of structures [Armstrong]
The set theory brackets { } assert that the member is a unit [Armstrong]
Powers must result in some non-powers, or there would only be potential without result [Armstrong]
How does the power of gravity know the distance it acts over? [Armstrong]
Properties are not powers - they just have powers [Armstrong]
The pure present moment is too brief to be experienced [Armstrong]
'Mereological Nominalism' sees whiteness as a huge white object consisting of all the white things [Armstrong]
'Mereological Nominalism' may work for whiteness, but it doesn't seem to work for squareness [Armstrong]
'Class Nominalism' says that properties or kinds are merely membership of a set (e.g. of white things) [Armstrong]
'Class Nominalism' cannot explain co-extensive properties, or sets with random members [Armstrong]
'Class Nominalism' may explain properties if we stick to 'natural' sets, and ignore random ones [Armstrong]
'Predicate Nominalism' says that a 'universal' property is just a predicate applied to lots of things [Armstrong]
Concept and predicate nominalism miss out some predicates, and may be viciously regressive [Armstrong]
'Resemblance Nominalism' says properties are resemblances between classes of particulars [Armstrong]
'Resemblance Nominalism' finds that in practice the construction of resemblance classes is hard [Armstrong]
'Concept Nominalism' says a 'universal' property is just a mental concept applied to lots of things [Armstrong]
It is claimed that some universals are not exemplified by any particular, so must exist separately [Armstrong]
If properties and relations are particulars, there is still the problem of how to classify and group them [Armstrong]
One moderate nominalist view says that properties and relations exist, but they are particulars [Armstrong]
Should we decide which universals exist a priori (through words), or a posteriori (through science)? [Armstrong]
Most thinkers now reject self-predication (whiteness is NOT white) so there is no Third Man problem [Armstrong]
Armstrong holds that all basic properties are categorical [Armstrong, by Ellis]
Rather than take necessitation between universals as primitive, just make laws primitive [Maudlin on Armstrong]
Armstrong has an unclear notion of contingent necessitation, which can't necessitate anything [Bird on Armstrong]
Regularities are lawful if a second-order universal unites two first-order universals [Armstrong, by Lewis]
Science depends on laws of nature to study unobserved times and spaces [Armstrong]
Each subject has an appropriate level of abstraction [Armstrong]
If you know what it is, investigation is pointless. If you don't, investigation is impossible [Armstrong]
Actualism means that ontology cannot contain what is merely physically possible [Armstrong]
Dispositions exist, but their truth-makers are actual or categorical properties [Armstrong]
It is likely that particulars can be individuated by unique conjunctions of properties [Armstrong]
Realist regularity theories of laws need universals, to pick out the same phenomena [Armstrong]
A naive regularity view says if it never occurs then it is impossible [Armstrong]
Newton's First Law refers to bodies not acted upon by a force, but there may be no such body [Armstrong]
A good reason for something (the smoke) is not an explanation of it (the fire) [Armstrong]
The raven paradox has three disjuncts, confirmed by confirming any one of them [Armstrong]
Unlike 'green', the 'grue' predicate involves a time and a change [Armstrong]
Best explanations explain the most by means of the least [Armstrong]
The identity of a thing with itself can be ruled out as a pseudo-property [Armstrong]
Past, present and future must be equally real if universals are instantiated [Armstrong]
Universals are just the repeatable features of a world [Armstrong]
All instances of some property are strictly identical [Armstrong]
The laws of nature link properties with properties [Armstrong]
A universe couldn't consist of mere laws [Armstrong]
Science suggests that the predicate 'grue' is not a genuine single universal [Armstrong]
To explain observations by a regular law is to explain the observations by the observations [Armstrong]
Induction aims at 'all Fs', but abduction aims at hidden or theoretical entities [Armstrong]
If everything is powers there is a vicious regress, as powers are defined by more powers [Armstrong]
Negative facts are supervenient on positive facts, suggesting they are positive facts [Armstrong]
Absences might be effects, but surely not causes? [Armstrong]
Oaken conditional laws, Iron universal laws, and Steel necessary laws [Armstrong, by PG]
Nothing is genuinely related to itself [Armstrong]
We can't deduce the phenomena from the One [Armstrong]
The necessary/contingent distinction may need to recognise possibilities as real [Armstrong]
Universals are abstractions from states of affairs [Armstrong]
Universals are abstractions from their particular instances [Armstrong, by Lewis]
Properties are contingently existing beings with multiple locations in space and time [Armstrong, by Lewis]
In recent writings, Armstrong makes a direct identification of necessitation with causation [Armstrong, by Psillos]
Without modality, Armstrong falls back on fictionalism to support counterfactual laws [Bird on Armstrong]
The truth-maker for a truth must necessitate that truth [Armstrong]
Correspondence may be one-many or many one, as when either p or q make 'p or q' true [Armstrong]