ABSTRACT
The expression "logical thinking" has been used to describe the subject matter of a variety of developmental investigations. Whereas logical deduction in the strict sense is virtually the only inferential ingredient required in syllogistic reasoning tasks, the situation is different in the transitivity of length problem as Falmagne has clearly argued. More revealing characterizations of the class of logical truths are possible, but for present purposes the distinction between logical and nonlogical truths is sufficiently clear to allow people to sidestep complicated philosophical questions about the kind of difference obtaining between them. The classic conservation studies bear as much on children's grasp of natural law as on their grasp of logical truth. For the clarification of the distinction, it may be pointed out that a reasoning task may include logical thinking in the strict sense as one component, and also include other sorts of reasoning as well.
