Josiah Royce 
Primer of Logical Analysis [PDF ebook] 
For the Use of Composition Students

Whilst the greatest effort has been made to ensure the quality of this text, due to the historical nature of this content, in some rare cases there may be minor issues with legibility. To be sure, then, that we understand a sentence, we must be able to say, when any new and equally well-understood sentence is put beside the first, whether the new sentence is in meaning equivalent to the first, or consistent with the first, or deducible from the first, or opposed to the first. Yet other questions may be asked about the relative force of two sentences; but these are enough for the present. Let us explain what we mean by them.