Paragraph 1 | Perhaps enough has been said about the proof of necessity, how it comes about and how it differs from the proof of a simple statement. |
Paragraph 2 | Having made these distinctions we next point out that the expression 'to be possible' is used in two ways. |
Paragraph 3 | That which is possible in each of its two senses is convertible into its opposite, not however in the same way: |
Paragraph 4 | These matters will be treated more definitely in the sequel; |