In the last chapter of Mind & Cosmos, Nagel deals with what is likely the most difficult issue: how can evolutionary naturalism be expanded in order to accommodate values? A large group of philosophers, at least from Hume on, hold that the question does not really pose any problem. Values, such as good and evil or right and wrong, depend on our reactions and attitudes toward pleasure and pain. Value judgments are nothing but expressions of feelings of approval or disapproval over things. It is worth noting, therefore, that such a subjectivist position on values grounds the truth of evaluative judgments in motivational dispositions amenable to evolutionary rendition. One of the leading advocates of that position in recent times is Sharon Street. In a famous article, titled A Darwinian Dilemma for Realist Theories of Values (Philosophical Studies, 2006), she observed that motivational dispositions arose out of natural selection because of their fitness-enhancing capacity, for example, they aided individual survival by promoting social cooperation, care of children, avoidance of harmful behavior, and so on. In contrast with perceptual judgments, which need to relate to mind-independent reality in order to increase reproductive success of organisms, such motivational judgments do not refer to facts whatever conceived. As a consequence, Street underlined that value realism is superfluous for a Darwinian perspective. Values are expressions of our attitudes and do not refer to any mind-independent reality as though they were, according to the famous Mackie's expression, “part of the furniture of the world”. According to Street, the evolutionary account of evaluative judgments forces us to discard any kind of realism about values.
(Illustration of Charles Darwin and the variety of life that intrigued him by Ned M. Seidler)
As is well known, Nagel's preferred position concerning value judgments is a form of realism. He developed it in many articles and mainly in The View from Nowhere (Oxford University Press, 1986). In Mind & Cosmos, Nagel confronts his tenets with subjectivism more directly. In order to make clear what is at issue here I begin by setting out some points in which Nagel's value realism may be summarized:
- Realism states that truth does not depend on our responses. We can identify the right answer by reflection or deliberation;
- Realism states that evaluative judgments can often be explained by more general or basic evaluative truths together with the facts that bring them into play. Sometimes truths can be explained referring to natural facts; but realism is not a metaphysical position and does not add new kind of properties or facts: “A reason for action is an ordinary fact, such as the fact that aspirin will cure your headache, and its being a reason is just its counting in favor of your taking aspirin or my giving you some.” (113);
- Realism explains moral sense as a faculty that aims to identify those facts that count for and against certain courses of action; therefore, moral sense amount to a sort of cognitive faculty and reasons are depicted by Nagel as basic or fundamental truths;
- Values or evaluative judgments are the most basic level of reality, we cannot explain them by relying on something more basic; therefore, the main difference between subjectivism and objectivism is in the order of normative explanation: “That there is a reason to do what will avoid grievous harm to a sentient creature is, in a realist view, one of the kinds of things that can be true in itself, and not because something of a different kind is true. In this it resembles physical truths, psychological truths, and arithmetical and geometrical truths.” (102)
Despite Nagel admits that the contrast between subjectivism and realism does not apply to basic value judgments as those concerning pleasure and pain, it remains a big distance between the two conceptions of practical reason or deliberation.
In the realist interpretation, pleasure and pain have a double nature. In virtue of the attraction and aversion that is essential to them, they play a vital role in survival and fitness, and their association with specific biological functions and malfunctions can be explained by natural selection. But for beings like ourselves, capable of practical reason, they are also objects of reflective consciousness, beginning with the judgment that pleasure and pain are good and bad in themselves and leading on, along with other values, to more systematic and elaborate recognition of reasons for action and principles governing their combination and interaction, and ultimately to moral principles (111)
Human beings have the capacity to be motivated by value, they live, we might say, in a world endowed with values. Not only they feel pain and pleasure but judge it bad or good, right or wrong. Practical reason is the ability both to recognize what counts as reason and to judge what course of action is in accord with what is required by circumstances. To realize this capacity human mind should be capable of conscious control of actions and a certain degree of free will.
I respond consciously to value when I decide to give you aspirin because I learn that you have a headache and I know that aspirin will make it better. Of course I want your headache to go away, but that too is the result of my recognition that headaches are bad. The explanation of my action refers to these facts about headaches and aspirin in their status as reasons – as counting for and against doing certain things (113)
Given that practical reason, according to the realist theory, must include the conscious control and the free will of a unified subject, what might be difficult to explain is how a faculty which has evolved to detect reasons could lend itself to a Darwinian account of its evolution or, in other words, how can be possible that some living organisms have developed the capacity to control their actions in response to reasons and values? Nagel thinks that realists should embrace a teleological view according to which the capacity to responding to values gradually has evolved from elementary forms of live, such as bacteria, to more complex beings equipped with intentionality and the capacity to recognize their own good. Since life has evolved in an astonishing richness of forms (remember Darwin's famous expression “infinite forms the most beautiful”), also the world of values should be conceived of as pluralistic. This means that good and bad pertain to specific characters of certain beings which must be capable of perceiving them or, in other words, of being conscious.
This is how a realist account can accommodate one of the things that make subjectivism seem most plausible, namely the fact that what we find self-evidently valuable is overwhelming contingent on the biological specifics of our form of life. Human good and bad depend in the first instance on our natural appetites, emotions, capacities, and interpersonal bonds.” (119).
However, the contingent aspect of values does not affect the overall teleological structure of the universe. The contingency related to specific forms of conscious life in part explains how it is possible that subjective perspectives on the world have evolved within an objective natural order. Moreover, it emphasizes a major point in Nagel's theoretical position: knowledge should be conceived as an endless and gradual advance from subjective to objective stance, from the particular ways of judging toward the unattainable general point of view of the universe.