伦理与演化博弈:道德起源与本质的哲学探究

Ethics and Evolutionary Game Theory:A Philosophical Study of the Origin and Nature of Morality

伦理学研究的道德价值与行为规范似乎无法在客观世界的经验事实中找到踪影,也不可能从其中推演出来。既然科学是研究客观经验事实的学问,那么伦理学与科学似乎无法相容。可是,人类是自然之物,关于人的客观事实似乎不可能跳出科学的范畴,因此,伦理学与科学的不相容是个大问题。然而,科学解释有两种类型:一种为研究事物“动力因”的进路,另一种为研究事物“目的因”的进路。物质科学的自然规范性属于前一种,达尔文进(演)化论则属于后一种。道德规范在前一种进路中得不到解释其实不足为奇,因为解释它需要知道它是如何演化出来的。达尔文早已有关于道德起源的思想和初步理论,之后演化博弈论又提供了更丰富的资源,但仍然与我们的目标存在差距。结合集体或社会实在论的相关思想,可以更有效地解决伦理学与科学相悖的难题。

It appears that the moral values and behavioral norms,which are subjects of ethical research,cannot be found in the objective facts of the world,nor can they be deduced from them.Since science is the study of objective facts,ethics and science seem incompatible,just as religion and science are incompatible.However,human beings are natural objects;according to Bertrand Russell,we are no more than special arrangements of atoms.We have subjective experience and opinions that are not factual,just as we have opinions about the world that are not scientific,but ethics is not the collection of people's subjective moral opinions any more than science is a collection of people's opinions of the world.Ethics studies people's objective judgements about moral matters,namely values and norms,and so its incompatibility with science is a big problem.However,an incompatibility with judgements in material(or physical)sciences does not mean incompatibility with all scientific judgements.When we explain natural phenomena,we use at least two types of explanatory approaches.One is the"efficient cause"approach,and the other is the"final cause"or"end cause"approach.For example,physics is an exemplar of the former approach,while Darwinian evolutionary theory exemplary of the latter.From the apparent fact that one thing comes into existence as being selected for its function"by nature"seems to legitimately provide an explanation for its existence,we see that evolution by natural selection is a model of scientific explanations that uses the purpose or function that an organism serves as explanans.Therefore,it is not surprising that ethics cannot be explained by the efficient causal approach,because the explanation requires knowing how morals have evolved to serve some functions(i.e.having been selected in the struggle for survival).Darwin had developed preliminary theories on the origin of morality,and later evolutionary game theory provided even richer resources,even though there were stll remaining gaps.For one thing,Darwinian explanation of the origin of moral sentiments,such as sympathy and other altruistic emotions,does not yet explain why there are moral principles and values.It seems at most to explain why people occasionally follow what we regard as moral principles,but why should we admonish the violation of the principles that evolution does not seem to care about?We then further discuss the idea that moral principles evolve by natural selection,namely,the evolutionary game advantage of being rational or adhering to principles of action,including moral principles.It turns out that following moral principles is a better survival strategy,all things being equal,than a primitive appeal to altruistic sentiments on a case-by-case basis.However,the leading theory of such a naturalistic account of morality is anti-realist in its insistence that there are no moral facts,and moral judgments are not factual judgments,rather,they are emotive or proscriptive judgments of right or wrong.We further argue in this paper that moral realism is defensible if we acknowledge the contribution of such works on collective or social realism by Thomasello and Searle.The idea is that evolutionary pressure,both biological and cultural,should not be simply understood as giving rise to individual physiological and psychological profiles,since it also gives rise to social structures for groups or societies.The emergence of language and reason allowed human beings to create institutions that codify moral principles in the fabric of their social reality.Such reified behavioral principles or values are the factual basis for judgments of rationality including morality.And here lies the final piece of the argument for moral realism and for the reconciliation of ethics and science.