Download this publication - PULP

The content and justification of rationality review 49
which judicial scrutiny of law and state conduct may be said, in the familiar
metaphor, to ‘vary in intensity’.
3.1 Reasonableness and rationality
The appropriate point of departure is the notion of reasonableness. Simply
put, an act is reasonable, in everyday life, if the reasons in its favour defeat
the reasons militating against it. So to judge an act’s reasonableness involves
an evaluation of competing considerations, costs and benefits, likely
consequences and side effects, and a decision, on balance, that the ‘reasons
for’ defeat the ‘reasons against’. Another familiar metaphor is that of
weighing or balancing the relevant considerations against one another. 57
Obviously, what is reasonable depends on the context, for one can only
determine which considerations are relevant and what importance to attach
to each in the light of concrete circumstances.
So interpreted, however, deciding whether an act is reasonable is
identical to deciding whether that act is justified, since to say that an act is
justified means nothing if it does not mean that the reasons for it defeat all
countervailing reasons. But public law usually distinguishes between
judgments that acts are reasonable and judgments that acts are justified. The
standard of reasonableness is usually thought to be more accommodating
than the requirement that acts be justified, for the former leaves latitude for
differences of opinion, for rival, but plausible views of what is justified in
the circumstances.
Public law draws this distinction for two reasons. The first is the
pervasiveness of reasonable disagreement concerning how one should act in
situations of choice. 58
Frequently, reasonable people will form conflicting opinions about what
kinds of considerations are relevant as well as how much weight to assign to
each; in doing so they must apply concepts, including moral and political
concepts, that are vague and subject to hard cases; to some extent, the way
they assess the evidence and weigh the relevant moral and political values is
shaped by their different life experiences; and often some of the competing
factors will be incommensurable. 59
57
Although weighing and balancing metaphors capture the truth of assessing competing
considerations, they are misleading to the extent that they imply that all reasons have a
comparable dimension of ‘weight’ measurable in a shared metric. That is not the case, for
many reasons are incommensurable. Two competing reasons, and thus the different
actions they support, are incommensurable where neither reason is weightier than the
other and yet they are not equal in weight either: J Raz The morality of freedom (1986) 322. In
such circumstances, neither reason is defeated, so it is reasonable to choose either action:
J Gardner & T Macklem ‘Reasons’ in J Coleman & S Shapiro (eds) The Oxford handbook of
jurisprudence and legal philosophy (2004) 440 470 - 474.
58
These are the factors discussed by J Rawls in Political liberalism (2005) 56 - 57.
59 See n 57 above.