Kant on Predicates

Kant considered the role of the predicate in a statement of predication; and, found it necessary to classify predicates according to the dichotomy determining / non-determining. as will be seen, this viewpoint can be applied too simplistically.

§1: Kant's Taxonomy of Predicates

for Kant the class of logical predicates is co-extensive with the class of all predicates. he says:

Everthing can become a logical predicate, even the subject itself may be predicated of itself. 1

thus, any word/phrase that is a predicate is a 'logical' predicate.

the class of logical (ie 'all') predicates is subdivided into two subclasses:

1: those which are not contained in the subject and which, when predicated of the subject, enlarge the subject. these are determining predicates; also known as 'real' predicates.

2: those which are non-determining. one could also say that a non-determining predicate is not a real predicate; provided, that this did not mean 'not a predicate at all'. a non-determining predicate is still a 'real' (in the sense of genuine) predicate.

a predicate can fail to meet the criteria for a determining predicate by failing to convey no information not already contained in the subject; or, by failing to enlarge the subject; or, both (IMHO, the usual case).

as an example of a logical but non-determining predicate, consider 'a house is a house' --- a clear case of predicating the subject of the subject. it's a true statement; but, the predicate conveys nothing beyond what the subject says; and, it fails to enlarge the subject. the statement 'a house is a house' simply fails to convey any useful information at all.

§2: Is Existence a Predicate?

Kant now considers the classification of 'existence' as a predicate within this taxonomy of predicates. 2 Kant concludes that 'existence' is not a real predicate; however, it would remain a logical predicate within his taxonomy.

§2.1: The Black Swan

consider the statement 'black swans exist'. what information, if any, this statement contains or conveys depends on how 'exists' or 'existent' is defined. if 'existent' is defined as the root predicate of the linguistic frame of reference in which it is spoken; then, the statement conveys minimal information --- by definition (of 'root predicate') the statement would contain no information beyond that which is asserted by saying 'there are black swans'. to say 'a black swan is an existent' asserts only that a black swan is not nothing at all. it exists (in some sense) or it is an existent (of some sort).

in short, the root predicate is a logical predicate; but, it is completely uninformative. it conveys no new information about the subject; and, certainly no information that adds any further determinations (any further specificity) to the subject of the statement.

if 'exists' is defined as a [root predicate]-type indicator (or predicate), it conveys more information --- but not information contained within the subject. it conveys information about the mode of meta-phenomenal instantiation (if any).

a few centuries ago, biologists in Europe could have easily formed the concept of a black swan by mutating the concept of a white swan which was then (and still is) a phenomenological reality, [root predicate]-type 2, and was/is existentially instantiated as [root-predicate]-type 1. however, the concept 'black swan' would have been considered a phenomenological reality only because there was no evidence of meta-phenomenal instantiation either as an existential or ontological ([root predicate]-type 3) reality.

when the first travelers returned from Australia, they effectively said 'black swans exist' --- conveying information as to the mode of instantiation true of the subject. the concept of the subject (black swan) was not enlarged, altered or further determined.

suppose that all the black swans in the world are wiped out; by over zealous hunters, by disease or by some other means. 'black swans exist' would continue to *allege* a mode of meta-phenomenal instantiation; but, it would be a false statement. 'black swans do not exist' would convey accurate information about the subject.

suppose after this biological catastrophe, a biologist reconstructs living organisms from DNA samples previously taken from living black swans; and, then holds a press conference to announce 'black swans exist'. accurate information is again conveyed.

the point is, this information as to the mode of meta-phenomenal information is not contained within the subject. there is no way to inspect the concept of the subject, a phenomenological reality, to figure out whether black swans existed in Australia or whether they have already been wiped out or whether they've already been reconstructed.

thus, within a linguistic frame of reference where 'existent' is a [root predicate]-type indicator, information is conveyed by the predicate, 'existent'. however, this information as to the mode of meta-phenomenal instantiation is does not further determinate the subject; so, in Kantian terminology, 'existent' (schematically, any predicate that is a [root predicate]-type indicator in the linguistic frame of reference in which it is used), is not a 'real' or determining predicate. however, since it is genuinely informative, it is not merely a logical (non-determining) predicate as the root predicate would be.

consequently, one must conclude that a trionic taxonomy of predicates is needed:

  1. uninformative
  2. informative but not subject determinative
  3. subject determinative

[1]: Kant, Immanuel. 1966/1781. Critique of Pure Reason. translated by F. Max Muller. New York: Doubleday (Anchor Books). p. 401. A:595-599. B:623-627. [Back]

[2]: actually, he considers whether 'being' is a predicate; but, his analysis makes it clear that he is treating 'being' as a root predicate. since his analysis would apply equally to any predicate that is the root predicate within the linguistic frame of reference in which it is used, I present the analysis as it might be applied to 'existence', which is how the issues is usually discussed in the scholarly literature. [Back]