"Instrumental" and "value rationality" are terms scholars use to identify two ways individuals act in order to optimize their behavior.
Here are his original definitions, followed by a comment showing his doubt that humans are rational to believe that unconditionally right ends can be coordinated with conditionally efficient means.
Harvard professors John Rawls and Robert Nozick, globally recognised as expert practitioners of value rationality, produced mutually incompatible theories of distributive justice.
He reasoned value rationally to identify unconditionally just patterns of social action capable of providing humans with a permanent instrumental moral compass.
But he imagined groups of people in a hypothetical original position—stripped of personal interests and conditions—agreeing value rationally on intrinsically just institutions, forever worthy of voluntary obedience.
Let us assume that each person beyond a certain age and possessed of the requisite intellectual capacity develops a [value rational] sense of justice under normal circumstances.
… the reasonable is viewed as a basic intuitive [value rational] moral idea; it may be applied to persons, their decisions, and actions, as well as to principles and standards, to comprehensive doctrines and to much else.
[4]: 7, 82 Rawls reasoned that if citizens design an institution that always redistributes unplanned advantages fairly, they will sense its justice and obey it voluntarily.
[4]: 186 Rawls hoped that his theory of justice would generate a rational and reasonable "overlapping consensus.” Instead, it resulted in a double paradox, neither working nor acceptable as legitimate.
Rawls's institution destroys individual freedom to enjoy just deserts of pursuing one's ends with instrumentally chosen means.
Anarchy ended as it began, asserting that Rawls's justice as fair redistribution is unjust, and that only institutions of a minimal state—protecting established social advantages—can be just.
"[6]: 3 Translating into Weber's labels, Nozick was proposing to explain how principles—universal propositions connecting unconditional ends to conditional means—work instrumentally to identify conditionally-efficient-but-unconditionally-want-satisfying means.
[6]: 175–176 Nozick's assertion of a value rational human right to pursue individual utility resulted in the same double paradox as Rawls’s institution of justice as fairness.
He became a critic of the separation between instrumental and value rationality while describing and extending John Dewey's efforts to understand human intelligence.
[7]: xx Dewey wrote of "intelligence" rather than “rationality" because he considered reasoning to be a two-step way of thinking, not two distinct structural capacities.
Gouinlock wrote: "Realization of the good life [a contextual end for Dewey, not Nozick’s universal want satisfaction] depends … on the exercise of intelligence.
[9]:xxx, xxxv–vi Dewey, of course, was the sworn foe of all forms of rationalistic and absolutistic philosophizing … just [as] these traits are reappearing in contemporary moral thought.
They were hypothetical visions of ways of acting that might solve existing problems developmentally, restoring coordinated behavior in conditions that obstruct it.
If the conflicts between moral positions were all reducible to cognitive claims [of what it right], then we could settle such matters by appeal to familiar [deductive] procedures.
Courage, truthfulness, constancy, reliability, cooperativeness, adaptability, charity, sensitivity, rationality, and the like are distinguished because of their great [instrumental] efficacies in the life of a people.
One of the keys to this aim is to think of [instrumental] dispositions suitable to beginning and sustaining moral discourse and action, not bringing indisputable finality to them.
In 2009 he published The Idea of Justice, questioning whether unconditional value rationality used inconclusively by Harvard colleagues Rawls and Nozick is legitimate at all.
[10]: 4 More forcefully than Weber, he questioned the rationality of believing that unconditionally legitimate ends can be coordinated with conditionally efficient means.
"Justice as fairness" and "Entitlement theory" are "not only non-consequentialist but they also seem to leave little room for taking substantive note of consequences in modifying or qualifying the rights covered by these principles.
[10]: 637 For Rawls, there are eternally and universally just rules of fairness: "comprehensive goals,... deliberately chosen ... through an ethical examination of how one 'should' act [value-rationally].
Arbitrary reduction of multiple and potentially conflicting [value rational] principles to one solitary survivor, guillotining all the other evaluative criteria, is not, in fact, a prerequisite for getting useful and robust conclusions on what should be done.
Confirmation came in 2018 as the British journal The Economist, founded in 1843 on the utilitarian and libertarian principle of value-rational human rights, celebrated its 175th birthday.
It praised Rawls and Nozick for the very beliefs Gunlock and Sen identified as dogmatic: “those rights that are essential for humans to exercise their unique power of moral reasoning.
Both Rawls and Nozick practised ‘ideal theory’—hypothesising about what a perfect society looks like ..."[11]The first [value rational principle of liberals] is freedom: that it is "not only just and wise but also profitable ... to let people do what they want."
The second is the common interest: that "human society … can be an association for the welfare of all.”[12]Belief in value rationality—unconditionally true and just knowledge—continues to contaminate conditional instrumental rationality.