4. The deduction of the categories

The basic picture

• Experience requires intuitions and certain a priori concepts

• Since intuitions are given through the pure forms (space and time, presupposed by experience) and mathematics are derived from these intuitions, then all objects of experience will conform with mathematics

  • This explains why experience conforms with maths

• The categories effectively act as computing principles which determine the types of experience we can have

  • Concepts are general constraints, intuitions are singular representations

  • Objects are given through sensibility, thoughts in the understanding

The aim of the deduction

• Concern’s two questions: a) do we have a concept? b) is this concept legitimate?

  • We possess a concept ‘dog’ and it is legitimate because it can be exhibited in intuition (specifically, in sensible experience)

• Demonstrating that the pure concepts of the understanding (categories) are necessary for the synthetic unity of thinking is more difficult than demonstrating that space is legitimate (identifying its a priori origin was sufficient) (A90)

• The categories are the conditions of possible experience, but they are not the conditions under which objects are given in experience

  • This is because for the categories to have any bite they need to contain empirical content (i.e., the schematised categories) without which they are empty forms

The metaphysical deduction of the categories

• Kant aims to provide a concept (category) for each form of logical judgement

  • Thus, his aim consists in identifying these forms of logical judgement and then providing a concept (the category) for each form

• To derive the forms of logical judgement, Kant borrows from Aristotelian (syllogistic) logic which he believes has already identified all possible forms of judgement (logic is merely the study of these forms)

• He then offers a concept for each of these forms which are the categories

• The categories are the pure concepts of the understanding which make experience possible

  • “The same function that gives unity to the different representations in a judgement also gives unity to the mere synthesis of different representations in an intuition, which, expressed generally, is called the pure concept of the understanding.” (A79/B105)

What is the faculty of judgement?

• The faculty of judgement consists in bringing representations under rules and determining which representations fall under which rule

• The categories aim to provide a concept for each form of judgement

  • The ‘forms of judgement’ are intended as an exhaustive account of the types of judgements humans can possibly make

The table of judgemental forms

1. Quantity: Universal (all x), Particular (some x), Singular (this x)

2. Quality: Affirmative (x is), Negative (x is not), Infinite (x is non-F)

3. Relation: Categorical (a=b), Hypothetical (if a=b, a=c), Disjunctive (a=b or a=c)

4. Modality: Problematic (possibly), Assertoric (actually), Apodictic (necessarily)

The table of categories

1. Of quantity: Unity, Plurality, Totality

2. Of quality: Reality, Negation, Limitation

3. Of relation: of inherence and subsistence, of causality and dependence, of community

4. Of modality: Possibility-Impossibility, Existence-Nonexistence, Necessity-Contingency

• The first two categories are mathematical (relating to objects of intuition), and the latter two are dynamical (relating to existence) (B110)

Definition of the categories

• The pure concepts of the understanding through which experience is possible

• “Concepts of an object in general, y means of which intuition is regarded as determined with regard to one of the logical functions for judgements.” (A94/B128)

• They act as forms for all concepts similarly to how space and time are the forms of all intuitions

What are the aims of the transcendental deduction?

• Kant presents three slightly different versions in the Prolegomena and in each version of the Critique, meaning there are interpretative disagreements, but broadly:

1. The legitimacy thesis aims to secure that we have synthetic a priori knowledge of empirical reality

2. The restriction thesis argue that the categories make experience possible, but by that same token therefore cannot give knowledge of noumena

• Thus, Kant aims to reject the empiricist assertion that experience is the passive reception of representations — for Kant, we are active in constructing representations

  • This synthesis of the manifold (actually interpreting and understanding our representations) is not mere Humean idea-association, but requires categories which provide rules for how this synthesis is to occur

What is the transcendental argument for the categories?

1. Experience requires the synthesis of intuitions

2. Synthesis requires making judgements (and thereby the forms)

3. Judgements require the categories (so we can form concepts of our representations)

4. Therefore, experience requires the categories

• It is not clear what Kant means by experience (it could be conscious awareness, sense perception, or empirical knowledge) which leads to interpretive disagreements

The progressive (traditional) reading of the transcendental deduction

• Many interpret the deduction as an attempt to refute Cartesian scepticism

  • If Kant can secure the necessity of concepts which are the preconditions of experience, we do not need to doubt experience (it is certain i.e., indubitable)

• This would require that Kant proceed from premises that the sceptic would accept (so as not to be question-begging),

  • He would need to proceed from mere knowledge of self-consciousness (the synthetic unity of apperception) to ‘consciousness requires categorical synthesis, which entails empirical knowledge’

    • This is quite a task

The regressive reading of the transcendental deduction

• He begins from a specific assumption like ‘we have empirical knowledge’ and then aims to establish the necessary conditions for this experience

• Of course, this reading leaves Kant open to the criticism that he is wrong to assume we have a certain type of knowledge

  • Even then, the empirical knowledge Kant could be said to assume is extremely minimal, such as ‘an alteration has occurred’

• These two interpretations of Kant’s aims in the deduction do not contradict each other and might be held simultaneously

  • This interpretation might be especially illustrated in the case of causation — Kant is convinced it exists and so attempts to explain how it does

    • In fact, the first interpretation — that Kant is attempting to refute scepticism — implicitly uses this second strategy: he aims to show how we can have empirical knowledge given his belief we can have it

Quote demonstrating that the categories secure necessity of cause and effect

• “to the synthesis of cause and effect there attaches a dignity that can never be expressed empirically, namely, that the effect does not merely come from the cause, but is posited through it and follows from it.” (B124)

Quote clarifying the role of the categories

• “The categories of the understanding… do not represent to us the conditions under which objects are given in intuition at all.” (B122)

• This is because the categories are the forms of concepts, but without empirical content cannot be made homogeneous → this is why the schematised categories are so important