On Self-Organizing Systems and Their Environments - Understanding Understanding: Essays on Cybernetics and Cognition - page 5

FIGURE 2.
However, one should not overlook that the above expression, R ( H ) is
not a tautology, hence it must be a meaningful statement.* What it does,
is to establish a way in which we may talk about the existence of an
environment.
* This was observed by Wittgenstein, 6 although he applied this consideration to
the principle of mathematical induction. However, the close relation between the
induction and the relativity principle seems to be quite evident. I would even
venture to say that the principle of mathematical induction is the relativity princi-
ple in number theory.