The study of languages ought to be based upon a study of the necessary conditions to which signs must conform in order to fulfill their functions as signs. I have gradually been led to conclude that it is best to identify logic with this study, notwithstanding its thus being made to include something which has no bearing upon the strength of arguments. For there is but little of this superfluous matter, - too little to make a separate science of, - and it is needed for its linguistic and rhetorical applications, as well as having a value simply as truth; and a simpler unity is thus given to logic. I might, therefore, very well call it speculative semeiotic.