68

60

Yet in order to recognize error in our system
of graphs, we shall be obliged still further
to introduce the idea of time, which will
bring still greater difficulties. Time has usually
been considered by logicians to be what is called
“extra-logical” matter. I have never
shared this opinion. But I have thought that
logic had not reached that state of development
at which the introduction of temporal
modifications of its forms would not result
in great confusion; and I am much of
that way of thinking yet. The idea of time
really is involved in the very idea of an
argument. But the gravest complications
of logic would be involved in so far