The "Educationalists" believed that children were born as "blank slates", beginning their lives morally neutral. From this point of view, infants were neither inherently good or inherently evil. A child's nature and personality would develop over childhood, a period of time during which the educationalists believed a child was particularly impressionable. Adults surrounding a child could potentially have a very lasting effect on his personality.

Perhaps the man most influential to educationalist theory was John Locke. As Margaret J. M. Ezell puts it, his 1693 book Some Thoughts concerning Education presents the basic argument that "a child's mind must be educated before he is instructed, that the true purpose of education is the cultivation of the intellect rather than an accumulation of facts." According to Locke, the ideal education would instill a strong moral sense. In particular, a child should be taught virtue, wisdom, breeding, and learning. 34

This was possible because, among other reasons, a child's mind was a "tabula rasa", or blank slate (Locke originally used the term in his earlier work An Essay concerning Human Understanding, considered by modern philosophers to be his most influential work). Since the child's mind was so malleable, a parent could mold him with careful diligence. After all, one could write good moral sense upon a blank slate as well as numerous faults.30

Some Thoughts concerning Education was an extremely popular book. While earlier thinkers had espoused similar ideas, educationalist theory was largely ignored until Locke's publication. By 1750 over a dozen editions had been published, and the book was translated into French, German, Italian, Dutch, and Swedish. The huge popularity of Locke's book helped make popular the discussion of childhood as a separate stage of development from adulthood. Not only were parents influenced by his work, but so were other thinkers and writers of the time.

Even Locke's supporters, however, did not always agree with him. His opinion of the use of imaginative literature and the fine arts, for instance, was not particularly positive. He advocated two forms of literature for instruction, fables and religious works. In particular, he promoted the use of Aesop' s Fables. As to other literature (as well as other arts), however, Locke believed that they served no didactic purpose.31 In addition, he thought that passionate music would intensify emotions in the child, and that would damage the cultivation of reason. On the other hand, later educationalists saw the cultivation of the imagination a worthwhile pursuit, and encouraged the use of literature such as poetry and mythology.