Studies of comprehension of the quantifiers all and more are reported. The subjects were children between the ages of three and five. There were two main conditions. In one of these the objects to which the quantifiers related were enclosed in containers which either were or were not filled by the objects. In the other no containers were present. These conditions yielded substantially different response patterns. The relation of the findings to those typically obtained from Piagetian conservation tasks is discussed; and the implications for theories of semantic development are considered.