December 29 1957
RATlOKALm
(A)
Etymology
From the Late Latin* rat^onalitas. meaning rationality;
in turn, from the latin, rationalisfl meaning rational*
Uaags iS. Social ^i^oe fields
"Rationality*1 and its synonyms were important in the
vocabulary of philosophy and ethics before the social sciences
emerged as independent disciplines. The modern usage of "rationality" is very close to Aristotle 9 s concept of ealculative or deliberative intellectual virtue. In this sense, the rationality of
an action involves its derivation by logical processes from valid
premises. Rationality sometimes refers to processes of choice
that employ the intellective faculty; sometimes to the choices
themselves o The former emphasis is typical of earlier usage in
psychology, logic, and ethics; the latter emphasis predominates
in economics and sociology.
Thus, William James (Principles of Psychology 1390, eh0 22)
uses rationality as synonymous idth "the peculiar thinking process
ealled reasoning. 11 In this view* the rationality of a choice depends on the process of making it. Correspondingly, "irrational.
\
'
ity" in *psychol
" - ' ogical literature denotes domination of choice by
affective mechanisms (emotion, driven insftiaet^ impulse) rathe)
than intellective mechanisms (0, Allport in G. lindzsy* Handbook
of Social P8yoholo|jff> pp« 15-13). Because of this historical
identification of "rationality" idth the doctrine of "rationalism",
recent psychological writing tends to prefer terns like "cognitive
process* (Bruner* 4 Study of Thinking, 1956, P<> viii) or "intellective process."
Hence, "rationality11, in reference to the process
of choice;, appears to be disappearing from social science literature*
Economists have generally used "rationality" to d«no\® an
attribute of an action selected by a choice process* rather than
an attribute of the process, Thus, Dahl and Lindblom (Politics,
Boonomics» and Wel^are> 1953* p« 3d) say: "An action is rationa.1
to the extent that it is *correot3y £ designed to maxiiniae goal
achievement^ given the goal in question and the real world as it
exists,"
Iti sociology, similar definitions can be found in Max
$f®b$?£ Mannheim* and Parsons 0
to "rational.")
(Fareto prefers the term "logical"
The term is used rather loosely in sociology*
while in mathematical economics and statistical decision theory it
has received exact axiomatic treatment (see below)*
there is a somewhat distinct usage of "rational" in the writing of Max Weber and others on bureaucracy. In the ideal type of
"rational legal authority",, rationality means the conscious adaptation of the organisation to goals, and its operation through the
impersonal application of rules without deflection by the personal
goals of the functionaries* An approximate! synonym is Mannheim 9 s
phrase, "functional rationality11 (Man, and Society in an Age o£ Re
construction, 194% P» 53)»
Rationality
3 <=>
!
X
(C)
Definition
; ,'/
In a broad sense, rationality is behavior (a) that., is appropriate to the achievement of given goals (b) within the limits imposed by given conditions and constraints*
In particular contexts, terms (a) and (b) of the definition
nay receive more exact specification. Some of the more important
of these specialized uses ara:
(i) The goal may be assumed to take the form of
(or, in game theory* mlnifltffiidiig) the expected value,, over some time
interval, of a utility function* Further, the existence of the utility function may be cepived from postulates about the ordering and
consistency of the choosing organism's preferences a Thus, the
rational consumer of formal economic theory maximizes his expected
utility, and the rational entrepreneur maximises his expected profit.
If a distinction is wanted between this very strict species of rationality and more general forms, the former may ba termed "optimality'1,
the latter "adaptiveness" or "functionality",
(ii) The goal may be assumed to consist of criteria to ba
satisfied in an all«or~none way («.g<>, attainment of the level of
aspiration). Alternatives that conform to such a requirement of
rationality are eometisne© said to "satisfies",
(iii) The conditions and constraints referred to in the
general definition may be objective characteristics of the environment external to the choosing organism, they may be perceived characteristics* or they may be characteristics of the organism itself
RatloiiaXtiy
-4
that it takes as fixed and not subject to its own control. The line
between the first case and the other two is sometimes drawn by distinguishing "objective rationality", on the one hand* from "subjective"
or "bounded rationality", on the other*
(tr) the goals referred to in the definition nay be goals of
the choosing organism, goals of a social system to which ho belongs,
or goals imputed by the observer.
An unambiguous use of the term "rationality11 requires the user
to specify what assumptions he is making about both goals and condition!
Ho A. Simon