Thus, though it would be possible to interpret the
form which we take as the form of a tautology as that of a
contradiction & vice versa,
they
are
different in logical form, because though the apparent
form of the symbols is the same, what
symbolises in them is
different. & hence what follows about the symbols
from the one interpretation will be different from what follows
from the other. But the
difference between a & b is
not one of logical
form, so that nothing
will follow from this difference alone as to the interpretation of
other symbols. Thus, e.g.
p.q, p ⌵ q
|| seem symbols of exactly the
same logical form in the a–b
notation. Yet they say something entirely
different; &, if you ask why, the answer seems to be:
In the one case the scratch at the top has the
|| shape b, in the other the
|| shape a.
¤ The important thing is that the
|| interpretation of the
form of the symbolism must be fixed by giving an
interpretation to its
logical properties,
not by
giving interpretations to particular scratches.