This means that no single logic is strong enough to support the total construction of human knowledge. – Jean Piaget
In other words, knowledge of the external world begins with an immediate utilisation of things, whereas knowledge of self is stopped by this purely practical and utilitarian contact. – Jean Piaget
To express the same idea in still another way, I think that human knowledge is essentially active. – Jean Piaget
It is with children that we have the best chance of studying the development of logical knowledge, mathematical knowledge, physical knowledge, and so forth. – Jean Piaget
To-day it appears as though it may well be altogether abolished in the future as it has to some extent been mitigated in the past by the unceasing, and as it now appears, unlimited ascent of man to knowledge, and through knowledge to physical power and dominion over Nature. – Frederick Soddy