"If we ask whether the tick is a machine or an operator,
a mere object or a subject, the physiologist will reply that he finds receptors,
that is, sense organs, and effectors, that is, organs of action, connected by an
integrating device in the central nervous system. He finds no trace of an
operator.
To this the biologist will reply, 'You mistake the character of the
organism completely. No single part of the tick's body has the nature of
a machine; everywhere operators are at work'."
(..)"The relations between subject and object are best shown by the diagram
of the functional cycle (Fig. 3). This illustrates how the subject and the
object are dovetailed into one another, to constitute a systematic whole.
If we further consider that a subject is related to the same or to different
objects by several functional cycles, we shall gain insight into the first
principle of Umwelt theory: all animals, from the simplest to the most
complex, are fitted into their unique worlds with equal completeness. A
simple world corresponds to a simple animal, a well-articulated world to
a complex one"
Jakob von Uexküll (1934)
http://www.codebiology.org/pdf/von%20Uexk%C3%83%C2%BCll%20J%20(1934)%20A%20stroll%20through%20the%20worlds%20of%20animals%20and%20men.pdf
