It may be said that the basic characteristic of human behavior in general is that humans personally influence their relations with the environment and through that environment personally change their behavior, subjugating it to their control.

It is through others that we become ourselves.

What children can do with the assistance of others might be in some sense even more indicative of their mental development than what they can do alone

Childhood is a complex dialectical process characterized by periodicity, unevenness in the development of different functions, metamorphosis or qualitative transformation of one form into another, intertwining of external and internal factors, and adaptive processes which overcome impediments that the child encounters.

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

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

The child begins to perceive the world not only through his [or her] eyes but also through his [or her] speech