I found Justin Clarke-Doane’s recent paper “Morality and Mathematics: The Evolutionary Challenge” in the journal Ethics refreshing in the way it argued that “Evolutionary Challenge” arguments against moral realism follow the same logic as arguments against mathematical realism. (In brief, “Evolutionary Challenge” arguments against moral realism hold that if are our moral beliefs are the products of semi-random evolutionary processes, then different evolutionary histories would produce different moral beliefs and, therefore, moral realism is false.)
To make the analogy between moral and mathematical realism possible, Clarke-Doane defines “moral realism” and “mathematical realism” as “mind-and-language-independent array(s) of truths of the relevant sort”. I was delighted with this definition because it usefully separates two aspects of moral realism that are too often defined as a single aspect: 1) the reality of a mind-and-language-independent array of truths relevant to morality and 2) the reality of imperative oughts that are somehow (magically?) binding regardless of people’s needs and preferences.
Using this sensible definition of moral realism with no implication for the reality of imperative oughts leads directly to an “Evolutionary Confirmation” of moral realism rather than an Evolutionary Challenge.
After this good start, Clarke-Doane’s assumptions about biological and cultural evolutionary processes, while standard for Evolutionary Challenge discussions, are, unfortunately, too simplified to be useful for the purpose. These assumptions do not discriminate between selection forces for biology (reproductive fitness) and selection forces for cultural norms (whatever people find attractive). They also do not consider ultimate selection forces based in physical reality, such as synergistic benefits of cooperation in groups, which is arguably the ultimate selection force for both our moral biology (the biology underlying empathy, conscience, and so forth) and our enforced cultural moral standards.
However, combining Clarke-Doane’s definition of moral realism with a more sophisticated understanding of biological and cultural evolutionary processes wonderfully simplifies the problem of debunking the Evolutionary Challenge to moral realism (as Clarke-Doane defines moral realism without regard for imperative oughts).
The most direct way to illustrate that simplification is by understanding the ultimate selection force for both our moral biology and enforced moral standards, the synergistic benefits of cooperation in groups. The following are mind-and-language-independent truths about physical reality.
1) Independent agents can often, and intelligent agents can almost always, produce more benefits by cooperative efforts than by working only as individuals.
2) Cooperation often exposes cooperators to exploitation and altruistic cooperation (cooperation maintained by altruism) always does.
3) Exploiting other cooperators gets the individual the most benefits in the short term, and therefore can be attractive, but destroys potentially larger long term benefits of cooperation.
4) This problem in how to overcome short term self interest in order to sustainably obtain the benefits of cooperation in groups can be solved by a) agents being biologically inclined to altruistically accept the short term cost of not exploiting other cooperators, and b) punishment of agents who exploit other’s altruism.
5) Biological evolution implements this solution (point 4) by evolving emotions such as empathy, loyalty, guilt and shame (that motivate altruism), evolving the emotional experience of durable well-being that rewards altruistic cooperation in groups, and evolving the emotion indignation that motivates punishment of people who exploit altruism. All this biology is selected for by the reproductive fitness benefits of increased cooperation in groups.
6) As a separate process, cultural evolution exploits this solution (point 4) by selecting enforced cultural norms (enforced moral standards) that advocate altruism and punishment of people who exploit altruism. These enforced moral standards are selected for by whatever benefits of cooperation in groups people find attractive; reproductive fitness benefits may not be present.
7) Game theory provides altruistic strategies (composed of usually reliable, but still fallible heuristics) for choosing altruistic behaviors that have some protection against exploitation and are likely to increase the synergistic benefits of cooperation in groups. These mathematical altruistic strategies are also intrinsic to physical reality and universal.
Thus, the ultimate selection forces for both our moral biology and enforced moral standards is not “reproductive fitness”, but the synergistic benefits of altruistic cooperation based on mind-and-language-independent truths about physical reality. That is, morality defined as “Altruistic acts that also increase the benefits of cooperation in groups” is a mind-and-language-independent evolutionary adaptation that is innate to our physical reality.
By a similar argument, the ultimate selection force for human mathematics is not “reproductive fitness”, but the mind-and-language-independent innate conservation laws and symmetries that define our physical reality. So 2 + 2 = 4 not because our ancestors who believed that had a reproductive fitness advantage, but because it is required by the conservation laws that define our physical reality.
If moral and mathematical realism are defined as Clarke-Doane proposes and a suitably sophisticated understanding of biological and cultural evolution applied, the relevant question concerning evolution is not “The Evolutionary Challenge” to moral and mathematical realism, but “The Evolutionary Confirmation” of moral and mathematical realism.
For readers with a purely philosophical focus, it may be useful to clarify that the seven aspects of physical reality described above (concerning the ultimate selection forces for morality) are not assumed premises. They are claimed facts (in the normal provisional truth sense of science) whose ‘truth’ claims are largely based on explanatory power for known descriptive facts about morality and puzzles about morality. That explanatory power includes identifying the common underlying principle for virtually all past and present enforced cultural moral standards no matter how diverse, contradictory (slavery and homosexuality are or are not immoral), or bizarre (it is ‘immoral’ to eat shrimp and pigs or shave your beard). That explanatory power also answers moral puzzles such as “When is it immoral to follow the Golden Rule?” and “How can moral realism be consistent with both ‘pagan’ and ‘Christian” moral virtues that are almost opposite?”