This chapter discusses James’s views not only on habit, thought, and their mutual relations, but also on reflexes and instincts. It shows how the reflex arc is at the basis of James’s natural scientific psychology; how reflexes, instincts, and habits are intertwined; and how thought is enmeshed in their development over the lifetime of individuals. The chapter also discusses James’s assessment of the role of habits in the formation of character and the advice he gives to parents, teachers, and individuals. Finally, it reviews how thought begins with holistic consciousness and then develops by means of discrimination, comparison, and the “association of ideas” according to principles of contiguity and similarity. In doing so, it explains what James meant by “the blooming, buzzing confusion” of initial consciousness and how association by similarity is significant in distinctly human thought.