Symbols are not what they seem to be.
In “aRb”,
“R” looks like a substantive, but is not
one.
What symbolizes in “
aR
b” is that
R occurs
between
a &
b.
Hence “R” is
not the indefinable
in “
aR
b”.
Similarly in “φx”,
“φ” looks like a substantive but is not
one; in “~p”,
“~” looks like
“φ” but is not like
it.
This is the first thing that indicates that there
may not be
logical constants.
A reason against them is the generality of logic: logic cannot treat
a special set of things.
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