Nozick obviously wasn't discussing, and I'm not asking about, the calculus or mechanical meanings of 'differential'. ODO doesn't distinguish them; 'different' is synonymized with 'differential', and vv.
In 1, 2, 4: why didn't Nozick write 'different'?
In 3, 5-7: why didn't Nozick write 'differential'?
Nozick. Anarchy, State, and Utopia, Oxford: Blackwell, 1974: 155-6:(http://fs2.american.edu/dfagel/www/NozickExcerpt.html)
In contrast to end-result principles of justice, historical principles of justice hold that past circumstances or actions of people can create [1.] differential entitlement or [2.] differential deserts to things. An injustice can be worked by moving from one distribution to another structurally identical one, for the second, in profile the same, may violate people’s entitlements or deserts; it may not fit the actual history.
The entitlement principles of justice in holdings that we have sketched are historical principles of justice. To better understand their precise character, we shall distinguish them from another subclass of the historical principles. Consider as an example, the principle of distribution according to moral merit. This principle requires that total distributive shares vary directly with moral merit; no person should have a greater share than anyone whose moral merit is greater. (If more merit could be not merely ordered but measured on an interval or ratio scale stronger principles could be formulated.) Or consider the principle that results by substituting "usefulness to society" for "moral merit" in the previous principle. Or instead of "distribute according to moral merit," or "distribute according to usefulness to society," we might consider "distribute according to the weighted sum of moral merit, usefulness to society, and need," with the weights of the [3.]
differentdimensions equal. Let us call a principle of distribution patterned if it specified that a distribution is to vary along with some natural dimension, weighted sum of natural dimensions, or lexicographic ordering of natural dimensions. And let us say a distribution is patterned if it accords with some patterned principle. (I speak of natural dimensions, admittedly without a general criterion for them, because for any set of holdings some artificial dimensions can be gimmicked up to vary along with the distribution of the set.) The principle of distribution in accordance with moral merit is a patterned historical principle, which specifies a patterned distribution. "Distribute according to 1.0." is a patterned principle that looks to information not contained in distributional matrices. It is not historical, however, in that it does not look to any past actions creating [4.] differential entitlements to evaluate a distribution; it requires only distributional matrices whose columns are labeled by 1.0. scores. The distribution in a society, however, may be composed of such simple patterned distributions, without itself being simply patterned. [5.]
Differentsectors may operate [6.]
differentpatterns, or some combination of patterns may operate in [7.]
differentproportions across a society. A distribution composed in this manner, from a small number of patterned distributions, we also shall term "patterned." And we extend the use of "pattern" to include the overall designs put forth by combinations of end-state principles.
I first happened upon this para. from Introduction to Politics: First Canadian Edition (2012 1 edn, but ∃ 2016 2 edn). p. 87 Top.
From the right, Rawls's major critic has been the American philosopher Robert Nozick (1938—2002). Nozick was writing from a libertarian perspective, which calls for a state focused on protection of property rights. He put forward a procedural theory of justice in which the main concern is not the outcome (e.g., meeting needs) but the way in which property (in the broad sense, meaning anything possessed by an individual) is acquired. It is therefore a historical theory in which "past circumstances or actions of people can create differential entitlements or differential deserts to things" (Nozick, 1974, [Anarchy, State, and Utopia]: p. 155). Provided that the property was acquired fairly, then the owner has a just entitlement to it. Nozick considered any attempt to redistribute property, even through taxation, to be unjust.