Linguistics will have to recognise laws operating universally in language, and in a strictly rational manner, separating general phenomena from those restricted to one branch of languages or another.

It is one of the aims of linguistics to define itself, to recognise what belongs within its domain. In those cases where it relies upon psychology, it will do so indirectly, remaining independent.

In general, the philological movement opened up countless sources relevant to linguistic issues, treating them in quite a different spirit from traditional grammar; for instance, the study of inscriptions and their language. But not yet in the spirit of linguistics.

It is useful to the historian, among others, to be able to see the commonest forms of different phenomena, whether phonetic, morphological or other, and how language lives, carries on and changes over time.

Any psychology of sign systems will be part of social psychology - that is to say, will be exclusively social; it will involve the same psychology as is applicable in the case of languages.

It is only since linguistics has become more aware of its object of study, i.e. perceives the whole extent of it, that it is evident that this science can make a contribution to a range of studies that will be of interest to almost anyone.