 The so-called “psycho-neuro-endocrine system” has a well-established fourth partner in the immune system showing that its activity cannot be understood in isolation from these other systems. The models employed in one cognitive system are readily shared by the other and thus propagate underlying theoretical approaches and implicit directives. Postulating molecular-level and systems-level recognition states carries notions of “intentionality” (see the entry on  intentionality).  Alternatively, instrumentalist and eliminativist approaches argue that intentional descriptions are either only constructs of a useful idiom or that they should be dropped altogether (Dennett 1987; Churchland 1989). Intentional assignments reflect an ordering mechanism for phenomena otherwise difficult to characterize and thus susceptible to error (Matthen and Levy 1984). Errors must be understood in terms of reference to what end a system actually seemingly intends versus what it achieves in given circumstances. In the immune setting, autoimmunity signifies a dysregulated state that, in this context, signifies mis-directed intentionality of normal immune function (Matthen and Levy 1984: 361). Any attempt to frame this process in non-intentional terms would fail, as such descriptions do not invoke goals, expectations, unfulfilled intentions and the like. Accordingly, immunology cannot dispense with the intentional idiom and the associated psychological metaphors used in its descriptive language, if even only as a heuristic device (Rosenberg 1989: 38; Melander 1993: 239; Howes 2000). Strong arguments have been made that metaphors in the life sciences act as indispensable instruments of cognition and explanation in addition to providing a useful perspective on a research subject (Reynolds 2018). Indeed, despite neo-positivistic efforts to rid science of nonliteral meanings to permit an objective (neutral) description of nature, analogical thinking in science plays a variety of crucial epistemic functions (Hesse 1966; Fox Keller 2002).