 Types of behaviour do, no doubt, recur, so long as minds of the same kind are placed in the same kind of situations. The behaviour-patterns characteristic of a feudal baron were no doubt fairly constant so long as there were feudal barons living in a feudal society. But they will be sought in vain (except by an inquirer content with the loosest and most fanciful analogies) in a world whose social structure is of another kind. In order that behaviour-patterns may be constant, there must be in existence a social order which recurrently produces situations of a certain kind. But social orders are historical facts, and subject to inevitable change, fast or slow. A positive science of mind will, no doubt, be able to establish uniformities and recurrences, but it can have no guarantee that the laws it establishes will hold good beyond the historical period from which its facts are drawn. (IH 1993: 223–224)