Piaget's last writings, particularly those coauthored by Garcia [Piage
t and Garcia, 1974, 1989, 1991], contain both a coherent constructivis
t account of explanation in science [Piaget and Garcia, 1989] and spec
ific suggestions for revising the logic of operations as a logic of me
anings, based on the relevance logic of Anderson and Belnap [1975] - s
ee Piaget [1980] and Piaget and Garcia [1991]. The aim of the present
article is to demonstrate the interdependence of these two significant
developments in Piaget's later work, by examining the merits of Piage
t's revised logical competence model as a logic of causal explanation.
Whereas the logic of operations is sufficient as a logic of hypothesi
s testing, its basis in truth-functional logic provides too narrow a t
reatment of semantic issues to properly model causal explanation, a fo
rm of thought characterized by a strong interdependence of form and co
ntent. The logic of meanings, as an intensional logic, rejects the red
uction of meaning to truth conditions and introduces issues of relevan
ce and context into logic.