A central tenet of Montessori philosophy is that human beings exhibit certain predispositions that are universal, spanning age, cultural and racial barriers; they have existed since the dawn of the species and are probably evolutionary in origin. 'Montessori stresses the need to serve those special traits that have proved to be tendencies of humans throughout his history.' (Mario Montessori,). A tendency is a natural inclination that guides the individual to survive. These tendencies are universal and timeless, unchangeable, and intrinsic in the human. Montessori mentions 25-30 tendencies in her writings. (Baker, Kay)

“The conclusion is that we find in the soul of man some characteristics which are strong, as if they were hereditary, but are not inherited. They are strong and fixed like heredity…” (Montessori, Maria, The 1946 London Lectures, p. 100) “… there are some sentiments which are very deeply rooted in the soul of humanity. They are in our nature, in the nature of our adaptation to the group…These instincts, deeply hidden within the individual, are important. They are not connected to reason or consciousness. People cannot renounce them…We must conclude that there are things which are rooted in the unconscious of humanity…and cannot be eradicated…” (Montessori, Maria, The 1946 London Lectures, p. 98-99) “The tendencies are: adaptation to social life, the tendency to remain in one place and work, especially with the hands, artistic expression, spirituality-to love, to be happy, to be free sexually, to have riches, to have restriction or inhibitions, to have respect for the environment, to make personal sacrifice, to make a language to communicate socially, a tendency for exactness, discovery-to explore, to have freedom, to have independence, to have concern for living beings, to preserve life and self-preservation, to acquire knowledge, to have means of self-expression, to form society with others, to observe, to be active, to be disciplined, to maintain order, and to preserve ancient beliefs.” (Montessori, Maria, 1946 London Lectures, chapter, “The Study of Man”, pp. 93-101)