The terms, period, phase, stage, and level – all frequent in the literature on development – are examined in order to specify conceptual differences. The authors suggest that while level has no inherent temporal component, the other three refer to stretches of time and should be differentiated according to whether or not they refer to (a) part of a progression; (b) a recurrent state or event; (c) quantitative change, and (d) qualitative change. The four terms can be distinguished as different combinations of the given criterial elements.
Moreno A., Merelo J. J. & Etxeberria A. (1992) Perception, adaptation and learning. In: McMullin B. (ed.) Proceedings of the workshop “Autopoiesis and Perception”. DCU, Dublin: 65–70. https://cepa.info/5235
We attempt to distinguish, in a biological frame, ontogenetical adaptation from learning. Ontogenetical adaptation arises as a second order (sensorimotor) loop on the ground of the operational closure that provides autonomy and reproductive identity to the living system. Adaptation ensures, through perception, the functional correlation between metabolic-motor states and the states of the environment. Learning brings about a qualitative change in regard to adaptation, the most generic and simple form of optimization at an individual scale. It implies the idea of new knowledge, in the sense that the organism links what formerly appeared as an undistinguished whole. In other words, it means the capability to change its own codes of meaning. Finally, we outline some basic ideas for modelling an adaptive sensor embedded in a (partially) autonomous system, which implies the former distinction between adaptation and learning.