113

17

The following graph
*is an orange
*has red pulp
asserts that something is an orange and something has red pulp.
Now if I wish to express that the very same thing is an orange and has red pulp, I scribe it thus
(Is an orange
has red pulp
that heavy line expresses individual identity which logicians call numerical identity.
So
(teaches)
asserts that somebody teaches himself.
That is the substance of Conventions 5 and 6.
The former asserts that a point which belongs at once to two diagrams each of which by itself would be a graph, shall be understood to denote one individual object.
Convention 6 introduces the continuous line.