Section 4: Philosophy of Mind
ON THE POSSIBILLITY OF INTROSPECTION
Markus Werning
Heinrich-Heine-Universität Düsseldorf
LS Theoretische Philosophie
Universitätsstraße 1
40225 Düsseldorf
werning@phil-fak.uni-duesseldorf.de
Introspective thoughts seem to be almost ubiquitous companions of ours. The capacity
of introspection, moreover, is an indispensable component in the notion of ourselves as
human subjects. Although the existence of introspective thoughts strikes us intuitively
as indubitable, it is far from obvious how even their logical possibility can be defended
against rather plausible background assumptions. The opinions that introspective
thoughts are possible and that thought necessarily is productive and compositional (cf.
Fodor 1998), the paper argues, can only be reconciled if we assume that introspective
thoughts are formed in a symbolic (i.e. representational) structure that combines symbolic elements from sub-symbolic elements that can themselves be represented in the
structure. The overall conclusion of the paper is that introspection requires the possession of a phonetic language.
Not every second-order thought of one’s own (i.e., a thought of one’s own about
a thought of one’s own) is already an introspective thought. Three additional conditions
have to be fulfilled: First, an introspective thought is a report of a thought of one’s own
(where the notion of a thought subsumes all sorts of propositional attitudes including
perceptions, desires, beliefs and memories, cf. Fodor 1975). For this reason the wish that
I believed in God does not count as an introspective thought because the wish does not
report the belief, but merely aims at it. Second, the report of the thought is epistemically
basic and in particular non-inferred. In this respect the notion of introspection is likened
to that of perception (hence intro-SPECTION). This condition, e.g., rules out that an introspective thought be a thought that reports, say, an until then unconscious wish of the
person and does so on no other epistemic ground than that a psychoanalyst (or some encephalograph) informed the person about her wish. Third, the epistemic basis of an introspective thought is internally accessible for the subject (hence ‘INTRO-spection’).
According to a widely accepted view on mental representation, a representation is conceived of as a pair of an internal symbol (the bearer of the representation) and a (usually) external content (e.g. an actual or merely possible object or state of affairs). To become introspectively aware of a thought, thus, is to become aware of it by accessing its
internal symbolic component, not by accessing its external content. Some authors, in
contrast, have argued that one sometimes (or always) becomes aware of a perception of
one’s own simply by perceiving the external content of the perception (cf. e.g. Harman
1990). Those cases of second-order thoughts would not count as introspective according
to the third condition because they are not founded epistemically on anything internal to
the subject.
With these conditions for introspection at hand, the paper argues that, since an
introspective thought reports another thought by accessing its internal component, it
should be treated analogous to the direct report of a sentence by another sentence, i.e., as
quotation. Four ways to analyze quotation (respectively, its analogue in general symbolic structures) can be distinguished. The first way, lexical quotation, assumes that every
quotation is syntactically unanalyzable, i.e., lexical. Lexical quotation fails as an account
of introspection because it violates the constraint that symbolic structures be productive.
Since a productive structure builds infinitely many symbols from a finite set of lexical
symbols, no productive structure allows lexical quotation. All of the infinitely many
symbols would be quotable and would consequently contribute with more than finitely
many quotations of them to the lexicon.
The second view of quotation could be called holophrastic quotation because arbitrary (complex or primitive) symbols are taken as a whole and set in quotation marks
(or syntactically transformed in a specific other way by a function Q). To accomplish
this, the following syntactic rule is postulated: If t is a well-formed symbol of the language, then ‘t’ (or more generally, Q(t)) is a well-formed symbol of the language. This
rule is accompanied by a semantic interpretation according to which the semantic value
of ‘t’(generally speaking: of Q(t)) is t. Although holophrastic quotation is productive, it
is shown, that it violates another constraint, the principle of compositionality, if the
structure contains at least two symbols with the same semantic value. Compositionality
requires that the semantic value of a syntactically complex symbol is syntaxdependently determined by the semantic values of its syntactic parts. Formally this
means: Given the function of semantic evaluation M for a certain symbolic structure,
this structure is compositional just in case, for each n-ary syntactic operation S of the
structure, there is a semantic operation MS such that M(S(t1, ..., tn)) = MS(M(t1), ...,
M(tn)), provided S is defined for the array of symbols (t1, ..., tn). In symbolic structures
that (i) have the syntactic operation of holophrastic quotation Q with M(Q(t)) = t and (ii)
in which some symbols t and t* have the same semantic value M(t) = M(t*), one can
easily derive a contradiction to the principle of compositionality (The proof is provided
in the paper).
The third way, analytic quotation, unlike holophrastic quotation doesn’t apply a
syntactic operation of quotation to whole symbols however complex, but to their lexical
syntactic parts. Although slightly different, this method, too, violates the requirement of
compositionality, for very similar reasons holophrastic quotation does.
The failure of lexical, holophrastic and analytic quotation motivates an alternative, fourth way of analyzing quotation: phonetic or, more generally, sub-symbolic quotation. Here, the quotation of a symbol is constructed from representations of the subsymbolic parts of the symbol. The English expression ‘dog’, e.g., can unequivocally be
referred to by a concatenation of the representations ‘d’, ‘o’, and ‘g’ each of which represents a specific voiced dental consonant, a particular lower tongue vowel or, respectively, a specific voiced velar consonant. Representations of the phonetic parts of an expression, thus, enable the quotation of the expression. This view on quotation allows for
productivity and compositionality, but requires that sub-symbolic elements can themselves be represented in the symbolic structure. Unlike Mentalese, natural languages do
build symbolic elements, i.e., morphemes, from in the language representable subsymbolic elements, i.e., phonemes. This justifies the conclusion that introspective
thoughts are formed in an phonetic language whose phonetic parts are internally acces-
sible by the subject. Introspective thoughts, understood in the above sense and reconstructed as quotations, we may conclude, are only possible if the thoughts introspected
are formed in a phonetic language as instances of inner speech. Introspection thus requires the possession of a natural language. This a priori result is supplemented by a
number of psychological data (Morin, 1993) and neurobiological experiments (Craik &
al., 1999) indicating a correlation between introspection and inner speech. The possibility of becoming introspectively aware of other than phonetically structured thoughts,
e.g., introspecting perceptive or proprioceptive thoughts remains dubitable.
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