Dr. Montessori believed that no human being is educated by another person; he must do it himself or it will never be done. She therefore felt that the goal of the educational process should not be to fill the child with facts but rather to cultivate his own natural desire to learn. Children between the ages of two and six can pick up knowledge and understanding effortlessly, spontaneously and joyfully. Dr. Montessori called the child’s mind at this stage "absorbent" and compared its soaking in knowledge to a sponge’s soaking in water. She also discovered that during these years there are sensitive periods when a child shows unusual ability to acquire particular skills and when it is actually easier for him to learn those skills, that at any other time in his life.

She found that small children possess a deep-seated love of logic and order in the arrangement of things around them and will work best within a carefully prepared environment that gives order and logic to the impressions they receive. The classroom environment that she prepared was scaled to a child’s size and geared to his inner needs. It allowed him to experience the excitement of learning by his own choice and at his own speed. She believed that children are best able to comprehend their environment in very concrete ways, through immediate personal contact, and so she designed concrete tools to lead the child toward the ability to work in abstractions.

Feeling that there is an important correlation between muscular activity and learning, she incorporated movement into the use of the equipment, particularly constant use of the hands. Error-control factors were included that indicate a child’s mistake to him without his having to be told.

Last of all, Dr. Montessori concluded that freedom is a goal, not a starting point, and that educators have a responsible to train children’s characters to achieve self-discipline and self-direction, which result from the mastery of meaningful first hand experience and the fulfillment to the inner urge to expand and grow in one’s own way (without jeopardizing the rights of others to have this same privilege.)