ABSTRACT

Many other writers have stressed this type of error. It has been held, for instance, that there are two different senses of the word 'law', with and without normative implications, as in the laws of a society and scientific lalVs respectively, and that failure to realise this

has led to such diverse results as faulty ethical theories1 and mistakes about linguistic change on the part ofthe neogrammarians.2 Similarly, errors have been attributed to failing to distinguish between different meanings of 'is'. Aristotle has been considered guilty of this, and he in his turn accused Parmenides of making this mistake. Failure to distinguish between the psychological and logical sens es of the word 'idea' was held by Russell to have trapped Berkeley into his variety of Idealism,3 whilst Bradley accused it of misleading the Empiricists in their theory of the mind.4