Enlightenment Now: The Case for Reason, Science, Humanism, and Progress

To be sure, the argument from impartiality is incomplete. If there were a callous, egoistic, megalomaniacal sociopath who could exploit everyone else with impunity, no argument could convince him he had committed a logical fallacy. Also, arguments from impartiality have little content. Aside from a generic advisory to respect people’s wishes, the arguments say little about what those wishes are: the wants, needs, and experiences that define human flourishing. These are the desiderata that should not just be impartially allowed but actively sought and expanded for as many people as possible. Recall that Martha Nussbaum filled this gap by laying out a list of “fundamental capabilities” that people have the right to exercise, such as longevity, health, safety, literacy, knowledge, free expression, play, nature, and emotional and social attachments. But this is just a list, and it leaves the list-maker open to the objection that she is just enumerating her favorite things. Can we put humanistic morality on a deeper foundation—one that would rule out rational sociopaths and justify the human needs we are obligated to respect? I think we can.

According to the Declaration of Independence, the rights to life, liberty, and the pursuit of happiness are “self-evident.” That’s a bit unsatisfying, because what’s “self-evident” isn’t always self-evident. But it captures a key intuition. There would indeed be something perverse about having to justify life itself in the course of examining the foundations of morality, as if it were an open question whether one gets to finish the sentence or be shot. The very act of examining anything presupposes that one is around to do the examining. If Nagel’s transcendental argument about the non-negotiability of reason has merit—that the act of considering the validity of reason presupposes the validity of reason—then surely it presupposes the existence of reasoners.

This opens the door to deepening our humanistic justification of morality with two key ideas from science, entropy and evolution. Traditional analyses of the social contract imagined a colloquy among disembodied souls. Let’s enrich this idealization with the minimal premise that the reasoners exist in the physical universe. Much follows.

These incarnate beings must have defied the staggering odds against matter arranging itself into a thinking organ by being products of natural selection, the only physical process capable of producing complex adaptive design.⁷ And they must have defied the ravages of entropy long enough to be able to show up for the discussion and persist through it. That means they have taken in energy from the environment, stayed within a narrow envelope of conditions consistent with their physical integrity, and fended off assaults from living and nonliving dangers. As products of natural and sexual selection they must be the scions of a deeply rooted tree of replicators, each of whom won a mate and bore viable offspring. Since intelligence is not a wonder algorithm but is fed by knowledge, they must be driven to sop up information about the world and to be attentive to its nonrandom patterning. And if they are exchanging ideas with other rational entities, they must be on speaking terms: they must be social beings who risk time and safety in interacting with one another.⁸

The physical requirements that allow rational agents to exist in the material world are not abstract design specifications; they are implemented in the brain as wants, needs, emotions, pains, and pleasures. On average, and in the kind of environment in which our species was shaped, pleasurable experiences allowed our ancestors to survive and have viable children, and painful ones led to a dead end. That means that food, comfort, curiosity, beauty, stimulation, love, sex, and camaraderie are not shallow indulgences or hedonistic distractions. They are links in the causal chain that allowed minds to come into being. Unlike ascetic and puritanical regimes, humanistic ethics does not second-guess the intrinsic worth of people seeking comfort, pleasure, and fulfillment—if people didn’t seek them, there would be no people. At the same time, evolution guarantees that these desires will work at cross-purposes with each other and with those of other people.⁹ Much of what we call wisdom consists in balancing the conflicting desires within ourselves, and much of what we call morality and politics consists in balancing the conflicting desires among people.