● Two types of adaptationism are distinguished – ontological and methodological. The ontological thesis asserts that natural selection is the only important cause of the evolution of the vast majority of phenotypic traits; the methodological thesis tells scientists to construct idealized models of the evolution of phenotypic traits that ignore genetics and assume that organisms reproduce asexually. ● The ontological thesis fails to be true of a trait’s evolution if the genetic system prevents the fittest of the available traits from evolving to fixation and if the character states of present organisms are strongly influenced by the character states of their ancestors. ● An optimality model for a trait is important in evolutionary biology, even if the individuals in the population do not have the optimal trait value. ● Since science often progresses when different investigators adopt different approaches to the same problem, evolutionary biology may benefit by having some investigators be methodological adaptationists even if it would be bad for the science if all investigators did so.

The chapter investigates the evolutionary origins of human moral cognition. It discusses the relation of moral and legal theory and evolutionary theory. It reconstructs different perspectives on the evolutionary process. Influential current approaches are evolutionary psychology, theories of ontogenetic development on the basis of joint intentions and what one may call "evolutionary pluralism." The latter approach underlines the importance of many factors beyond natural selection that determine the genesis of a certain species and the stochastic nature of evolution. The methodological and theoretical foundations of these competing approaches are discussed. The problem of finding evidence for the properties of early humans is investigated. That state of research in paleoanthropology is recapitulated and discussed in terms of what it teaches us (and leaves undecided) about the genesis of human cognition, in particular moral condition. Taking into account the evidence and the most plausible evolutionary theory, it is argued that there is no compelling reason to assume that the moral principles underlying human rights are irreconcilable with human psychology.

Discovering why natural selection has left humans vulnerable to mental disorders will make psychiatry more sensible and effective, but defining the appropriate objects and kinds of explanation remains challenging. Asking how a disorder increases fitness is a mistake; disorders are not adaptations and they do not have evolutionary explanations. The correct objects of explanation are the traits that make all members of a species vulnerable to a disorder. Task 1 is to describe the evolutionary origins and functions of the traits involved. Task 2 is to describe the proximate processes that result in the disorder. Task 3 is to discover why natural selection left the traits vulnerable to malfunction. Five main kinds of explanation need to be considered: stochasticity, path dependence, mismatch, trade-offs that benefit the individual and traits that benefit gene transmission at a cost to the individual. Depression, addiction, eating disorders, autism and schizophrenia are used to illustrate the opportunities and challenges of framing and testing hypotheses about vulnerability. Multiple explanations are often needed for a single disorder, frustrating the wish for simplicity. However, recognising the fundamental differences between organic and designed systems offers opportunities for resolving – or at least understanding – some enduring controversies in psychiatry.