The real education in justice can only come where there are other children. This is one of many reasons why no child should long be solitary. Parents who have the misfortune to have an only child should do all that they can to secure companionship for it, ...A solitary child must be either suppressed or selfish--perhaps both by turns. A well-behaved only child is pathetic, and an ill-behaved one is a nuisance.
Source: On Education, especially in early childhood, 1926, by Bertrand Russell
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