Primer of Logical Analysis - For the Use of Composition Students #230634

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.