As Radu Bogdan explains in the preface, Predicative Minds: The Social Ontogeny of Predicative Thinking continues his earlier work on 'naive psychology'.  Understood as a competence for making sense of other minds, naive psychology also plays a role as a 'mind designer' – serving to enable the development of other, advanced mental faculties, such as reflexive thinking.  The present book focuses this developmental perspective on predicative thinking, and traces the roots of this competence to more rudimentary mental capacities that are steps in our mental development.  These roots indicate that predication is also bound up with the social nature of human being, in that some of these earlier mental capacities are intersubjective and communicative, presupposing a social context for their development.  The general claim within which the topic is situated is that if human beings have unique mental capacities, it is because of the uniquely human course of mental development that produces them.

Predicative thought deserves this attention because it marks a sharp division between animals and humans, as well as between young children and older children.  The minds of children begin non-predicatively as do those of animals, but human children make a sudden transition to predicative thought as a normal stage in their development, which animals never do.  Further, predication seems to be the precondition for any more sophisticated kind of theorizing and reasoning; only predicative minds, Bogdan points out, go on to create art, technology, science and culture. 

The main critical device Bogdan employs is a distinction between predication proper and what he terms 'coinstantiation'.  Previous accounts of predication, he asserts, have failed to address the problem adequately and can mostly be regarded as merely accounts of coinstantiation.  To make this distinction, he introduces what he calls 'S-dimensions' and 'P-dimensions', which characterize the propositional output of our mental faculties.  The S-dimensions are the standard perspective on predication, which analyses the surface, structural features of the output.  These include grammatical structure, semantic content, logical form and the relevant conceptual relations involved in a given predicative proposition. The P-dimensions are somewhat more novel: genuine predication for Bogdan requires in addition the psycho-pragmatic elements involved in the mental act of intending to communicate through a particular utterance.  These dimensions would include an intended directedness and intended descriptiveness, as well as what Bogdan calls 'topic-comment-presupposition format'.  These are psycho-pragmatic in that they concern what the speaker is doing with a predicative proposition, rather than the form it happens to take.  Topic-comment-presupposition format draws attention to the fact that utterances take place, and become meaningful, in a context of present conversation with presupposed background knowledge.  Paul Grice's contrast between speaker's meaning and sentential meaning is referenced here to identify the philosophical context.  So, put in terms of Bogdan's intention to understand predication as a mental competence, there are two competences involved in predication, that enabling formal analysis and use of language (even if merely tacit) and that enabling one to navigate the use of language in a pragmatic, social context.

The bulk of the text recounts the developmental story of how predicative thought is produced through a redesign of more rudimentary mental capacities.  In short, I think it may be fair to say that Bogdan is describing predication as a 'crane' in Dennett's use of that term.  That is, while predication is not strictly reducible to these rudimentary capacities, it also does not require the intervention of anything not based in such capacities.   This developmental account begins by noting the extended period of helplessness and dependence on adults in human infants.  Physical coregulation, where adults assist in managing an infant's physiological states, soon becomes psychological coregulation at a distance, conveyed through expressions, gestures and other behaviors.  A child picks up the directedness of adult attention towards itself and responds with protodeclarative communication aimed at getting or maintaining adult attention.  This eventually become joint triangulation between the child, the adult and the world, as the child exploits external targets in the service of holding adult attention.  (The first image to pop into one's head here may well be of a child persistently dropping a toy that an adult has repeatedly returned to it.)  Sharing attention in this way functions to 'fix topics', which can become the basis of shared coreference in which the child grasps the intent of adult communicative acts.  This recognition of referential intent positions the child to imitate adult gestures and vocalizations as a step toward the use of conventional symbols for communication, preparing the ground for linguistic communication.

There is much more to Bogdan's developmental story, but this short sketch should give a flavour of how he proceeds with it.  Although this is based on psychological research into children's cognitive development, Bogdan's interest is in the philosophical significance of the thresholds of cognition an infant passes through.  What is important is the way in which earlier capacities come to be adapted, and exapted, to serve new functions in the ordinary course of development that takes place through adult-child social interaction.  This sort of account, rare in philosophy, is necessary to incorporate the evolutionary perspective that can make higher mental functions seem less mysterious accomplishments.

While quite novel and interesting, the treatment of the subject is overall rather general, perhaps unavoidably so -- in scarcely one hundred and sixty pages, Bogdan tries to elicit the philosophical significance of mental evolution, incorporating conclusions from developmental psychology.  No mean feat at that.  Philosophically, however, I see two problems with this book: one is that it is difficult to see exactly what philosophical, or for that matter what developmental psychological, problem of predication is being addressed, such that it might be solved by the work done here.  The unity of predication is mentioned several times, but explicated as 'the whole of predication is greater than the sum of its parts', a loose expression that serves far too many issues to be analytically useful.  The second problem is that his approach to the problem seems to be only weakly motivated: the need for this approach turns on the inadequacy of previous accounts of predication, which Bogdan claims fail to be accounts of predication proper and are really accounts of coinstantiation.  But this seems to turn on Bogdan's definitional claim that predication proper requires both S- and P-dimensions, and this seems more to be asserted than argued for.  To my mind, the case here is overall weak philosophically, possibly due to the brevity, and the consequent generality, of the book.

That said, however, the approach to the subject here is fresh and challenging, and well worth further investigation.  Although somewhat technical, the philosophical language should not present a barrier to the relatively educated non-specialist, and the developmental story should be of considerable interest, to those in both developmental psychology and evolutionary psychology.

© 2009 George Williamson

George Williamson, University of Saskatchewan