Locke begins Some Thoughts with a few words about the importance of education. Nine tenths of the men we meet, he tells us, are as they are (good, bad, somewhere in between) because of their education. Education is what truly determines a man's character. Though every mind is born with particular inclinations (some are lazy, some industrious, some timid, some brave, and so on) the mind of a child is malleable, and education can form it significantly.
Given the power of education, he tells us, the aim of education should be nothing so modest as the formation of the intellect; rather the aim of education should be the formation of a whole human being. Education must focus on producing a healthy body and a sound mind. As we will see later in the book, the components of a sound mind include virtue, breeding, wisdom, and learning (in roughly that order of importance). Before turning to mind, though, Locke spends a few pages advising parents on how to strengthen their child's physical health.
Strength of the body, according to Locke, primarily involves the ability to endure hardship. In order to achieve a high level of durability, Locke believes the best thing for a parent to do is to expose the child to all the conditions that might potentially harm him in the future. Once the body becomes accustomed to these conditions, Locke reasons, they will no longer pose a threat to the child. The worst thing that a parent could do, on this view, is to coddle the child. The child's body will then be unused to any harsh conditions, and the moment they are exposed to such conditions (which, inevitably, they will be at some point) they will fall ill.
The first specific suggestion Locke makes is not to dress children too warmly. If they are exposed to the cold, he reasons, they will grow used to it, and it will not harm them. Consider the face, he tells us. We never cover our face in the cold, and, therefore, our face is the only part of our bodies that can completely withstand harsh conditions. If we exposed all of our bodily parts to the elements, they would all be as durable as the face.
In a similar vein, Locke suggests washing the child's feet with cold water every night. If the child becomes accustomed to cold, wet feet, then, when he gets caught in a rainstorm, or walks through a puddle, or any number of other likely, wet mishaps befall him, he will not come down with an illness. A child should also be kept outside through all weather — rain, snow, sleet, etc. Finally, a child should sleep in a hard bed so that he will grow accustomed to all sleeping conditions and not find it difficult to sleep outside of his own home. A hard bed, Locke thinks, also produces a heartier body.
Locke also has some other warnings, which do not quite fall into the above pattern. He strongly advises against dressing children in confining clothing, for instance, because he thinks that it constricts and manipulates their bone growth. He is also extremely concerned about a child's diet. The food that children eat, he thinks, should be as plain as possible. They should have little to no meat, and much bread. Fruits should also be kept to a minimum, and drinks should be weak and not too cold. Actually, he thinks that this is the ideal diet for all human beings, but he stresses that it is most important in children since they are in the process of developing. Finally, he advises that all children learn to swim so that they cannot drown, and that medicine only be given when a child is truly sick, and not for any preventative measures.