For primitive cybernetic systems which have no model of the world,
the command language is the only language that can be received.
If a system has a model of the world, as in the case of a human being
or a robot, the message received may not restrict the actions of the system
directly, but change the model of the wrld used by it. This will, obviously,
influence its actions in an indirect way, and, possibly, not immediately.
We call such messages statements. The content and the meaning
of a statement is in the knowledge it passes to the receiver.
It must be noted that when we simply say 'knowledge' we mean only
its impact on the genration of predictions and do not distinguish
between true knowledge and false (erroneous) knowledge.
Thus to be meaningful, a sentence must meet the same requirement as a piece of knowledge:
we must know how to be able to produce predictions from it, or produce
tools which will produce predictions, or produce tools to produce such
tools, etc. If we can characterize the path from the statement to
predictions in exact terms,
the meaning of the statement is exact. If we visualize this path
only vaguely, the meaning is vague. If we can see no path from a
statement to predictions, this statement is meaningless.
We do not identify meaningless with worthless. Since our criterion
of the meaningful includes a reference to the process of deriving
predictions, the meaning is to some extent subjective, and what is
meaningless for one person may be meaningful for another.
Furthermore, seemingly meaningless statements may lead to --
through some mysterious processes in our brain -- new ideas and
Our criterion of the meaningful should be used as a guide for making
our ideas more clear and precise, not as a reason for categorical
Copyright© 1997 Principia Cybernetica -
Referencing this page
Oct 6, 1997 (modified)
Sep 1991 (created)