Psychology teaches us at every step that though two types of activity can have the same external manifestation, whether in origin or essence, their nature may differ most profoundly.

Learning is more than the acquisition of the ability to think; it is the acquisition of many specialized abilities for thinking about a variety of things.

Experience teaches us that thought does not express itself in words, but rather realizes itself in them

Thought is not merely expressed in words, it comes into existence through them

Pedagogy must be oriented not to the yesterday, but to the tomorrow of the child's development. Only then can it call to life in the process of education those processes of development which now lie in the zone of proximal development

Human learning presupposes a specific social nature and a process by which children grow into the intellectual life of those around them

A word devoid of thought is a dead thing, and a thought unembodied in words remains a shadow.