The four levels are:
1. expressive-symptomatic -- expression inner states of emotion/
feeling (e.g., cries, laughter);
2. releasing-signalling -- trying to elicit a response in the receiver
(e.g., growling);
3. descriptive -- communicating impressions/ideas which can be
true or false (e.g., news reports);
4. argumentative -- reasoning which can be valid or invalid (e.g.,
generalizations like "the free market is the best economic
system").
My reference is John C. Eccles' _Evolution of the Brain: Creation
of the Self_ (1989).
Applied to the case of octopi, I guess they are on level two.
Getting them to level four, if this is at valid, is the goal of
uplifting put into linguistic terms.
Verily,
Daniel Ust
http://freeradical.co.nz/