Behavior is characterized in humans by the personal influence of their relations with the environment and through that environment personally change their behavior, subjugating it to their control.
Behavior is a thing whereby two instances may have the same external manifestation, and yet their nature may differ most profoundly.
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.
Cooperation is linked to maturity. 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.
Good behavior is often overvalued in a child. It is rarely good little boys and girls who become people with great passions and great minds who accomplish great deeds, who possess strong feelings.
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.
Play is a domain in which the child is always behaving beyond his age, above his usual everyday behavior.
Play is a domain in which the greatest achievements are possible, achievements that tomorrow will become a child's basic level of real action.
Play contains, in a concentrated form like the focus of a magnifying glass, all developmental tendencies.
