Lorenz proposed in his (1935) articulation of a theory of behavioral instincts that the objective of ethology is to distinguish behaviors that are “innate” from behaviors that are “learned” (or “acquired”). Lorenz’s motive was to open the investigation of certain “adaptive” behaviors to evolutionary theorizing. Accordingly, since innate behaviors are “genetic”, they are open to such investigation. By Lorenz’s light an innate/acquired or learned dichotomy rested on a familiar Darwinian distinction between genes and environments. Ever since Lorenz, ascriptions of innateness (...) have become widespread in the cognitive, behavioral, and biological sciences. The trend continues despite decades of strong arguments that show, in particular, the dichotomy that Lorenz invoked in his theory of behavioral instincts is literally false: no biological trait is the product of genes alone. Some critics suggest that the failure of Lorenz’s account shows that innateness is not well-defined in biology and the practice of ascribing innateness to various biological traits should be dropped from respectable science. Elsewhere (Ariew 1996) I argued that despite the arguments of critics, there really is a biological phenomenon underlying the concept of innateness. On my view, innateness is best understood in terms of C.H. Waddington’s concept of “canalization”, i.e. the degree to which a trait is innate is the degree to which its developmental outcome is canalized. The degree to which a developmental outcome is canalized is the degree to which the developmental process is bound to produce a particular endstate despite environmental fluctuations both in the development’s initial state and during the course of development. The canalization account differs in many ways to the traditional ways that ethologists such as Konrad Lorenz originally understood the concept of innateness. Most importantly, on the canalization account the distinction between innate and acquired is not a dichotomy, as Konrad Lorenz had it, but rather a matter of degree difference that lies along a spectrum with highly canalized development outcomes on the one end and highly environmentally sensitive development outcomes on the other end. Nevertheless, I justified the canalization account on the basis of a set of desiderata or criteria that I suggested falls-out of what seemed uncontroversial about Lorenz’s account of innateness (briefly): innateness is a property of a developing individual, innateness denotes environmental stability, and innate-ascriptions are useful in certain natural selection explanations (more below). From that same set of desiderata I argued (in my 1996) that neither the concept of heritability nor of norms of reactions—two concepts from population genetics—suffice to ground innateness. In this essay, I wish to provide further support of the canalization account in two ways. First, I wish to better motivate the desiderata by revisiting a debate between Konrad Lorenz and Daniel Lehrman over the meaning and explanatory usefulness of innate ascriptions in ethology. Second, I wish to compare my canalization account of innateness with accounts proposed by contemporary philosophers, one by Stephen Stich (1975), another by Elliott Sober (forthcoming), and a third by William Wimsatt (1986). (shrink)

I argue that too much attention has been paid to the Baldwin effect. George Gaylord Simpson was probably right when he said that the effect is theoretically possible and may have actually occurred but that this has no major implications for evolutionary theory. The Baldwin effect is not even central to Baldwin’s own account of ‘social heredity’ and biology-culture co-evolution, an account that in important respects resembles the modern ideas of epigenetic inheritance and niche-construction.

Will a synthesis of developmental and evolutionary biology require a focus on the role of nongenetic resources in evolution? Nongenetic variation may exist but be hidden because the phenotypes are stable (developmentally canalized) under certain background conditions. In this case, those differences may come to play important roles in evolution when background conditions change. If this is so, then a focus on the way that developmental resources are made reliable, and the ways in which reliability fails, may prove to be (...) of crucial importance to linking developmental and evolutionary biology. †To contact the author, please write to: 208 Hovland Hall, Philosophy Department, Oregon State University, Corvallis, OR 97331‐3902; e‐mail: jonathan.kaplan@oregonstate.edu. (shrink)

Organisms inherit various kinds of developmental information and cues from their parents. The study of inheritance systems is aimed at identifying and classifying the various mechanisms and processes of heredity, the types of hereditary information that is passed on by each, the functional interaction between the different systems, and the evolutionary consequences of these properties. We present the discussion of inheritance systems in the context of several debates. First, between proponents of monism about heredity (gene-centric views), holism about heredity (Developmental (...) Systems Theory), and those stressing the role of multiple systems of inheritance. Second, between those analyzing inheritance solely in terms of replication and transmission, and views that stress the multi-generation reproduction of phenotypic traits. A third debate is concerned with different criteria that have been proposed for identifying and delimiting inheritance systems. A fourth controversy revolves around the significance of the “Lamarckian” aspects of some of the inheritance systems that have been identified, such as epigenetic inheritance and behavioral inheritance, that allow the transmission of environmentally induced characters (i.e., “soft inheritance”). (shrink)

Recent and not so recent advances in our molecular understanding of the genome make the once prevalent view of the genome as a passive container of genetic information (i.e., genes) untenable, and emphasize the importance of the internal organization and re-organization dynamics of the genome for both development and evolution. While this conclusion is by now well accepted, the construction of a comprehensive conceptual framework for studying the genome as a dynamic system, capable of self-organization and adaptive behavior is still (...) underway. This work deals with the effect of such a conceptual shift on evolutionary thought. Specifically, I try to articulate the conceptual commitments and obligations of views that privilege explanatorily or causally the genome, its dynamics and mechanisms, over genes. I refer to this class of views as belonging to ‘the genome perspective’. (shrink)

Many natural and biological phenomena can be depicted as networks. Theoretical and empirical analyses of networks have become prevalent. I discuss theoretical biases involved in the delineation of biological networks. The network perspective is shown to dissolve the distinction between regulatory architecture and regulatory state, consistent with the theoretical impossibility of distinguishing a priori between “program” and “data”. The evolutionary significance of the dynamics of trans-generational and inter-organism regulatory networks is explored and implications are presented for understanding the evolution of (...) the biological categories development-heredity; plasticity-evolvability; and epigenetic-genetic. (shrink)

The dichotomy between Nature and Nurture, which has been dismantled within the framework of development, remains embodied in the notions of plasticity and evolvability. We argue that plasticity and evolvability, like development and heredity, are neither dichotomous nor distinct: the very same mechanisms may be involved in both, and the research perspective chosen depends to a large extent on the type of problem being explored and the kinds of questions being asked. Epigenetic inheritance leads to transgenerationally extended plasticity, and developmentally-induced (...) heritable epigenetic variations provide additional foci for selection that can lead to evolutionary change. Moreover, hereditary innovations may result from developmentally induced large-scale genomic repatterning events, which are akin to Goldschmidtian “systemic mutations”. The epigenetic mechanisms involved in repatterning can be activated by both environmental and genomic stress, and lead to phylogenetic as well as ontogenetic changes. Hence, the effects and the mechanisms of plasticity directly contribute to evolvability. (shrink)

Back in 1942, C.H. Waddington proposed a new mechanism of evolutionary change, which he termed “genetic assimilation”.1,2 The idea was that certain environmental or genetic factors can disrupt the normally canalized (i.e., stable) course of development of living organisms. This disruption may then generate phenotypic variation that could allow a population to persist in a novel or stressful environment until new mutations would eventually let natural selection fix (“assimilate”) the advantageous phenotypic variants.

Living organisms are caught between a hammer and an anvil, evolutionarily speaking. On the one hand, they need to buffer the influences of genetic mutations and environmental stresses if they are to develop normally and maintain a coherent and functional form. On the other, stabiliz- ing one’s development too much may mean not being able to respond at all to changes in the environment and starting down the primrose path to extinction. On page 618 of this issue, Queitsch et al.1 (...) propose that, in plants, the balance between stability and the potential for change is made possible in part through a protein involved in ‘heat- shock responses’ in a wide variety of species, from plants to insects. (shrink)

In this article I challenge the widely held assumption that human culture is inherited by means of social learning. First, I address the distinction between “social” learning and “individual” learning. I argue that most cultural ideas are not acquired by one form of learning or the other, but from a hybrid of both. Second, I discuss how individual learning can interact with niche construction. I argue that these processes collectively provide a non-social route for learned ideas to be inherited and (...) cumulatively modified. I conclude that human culture is not inherited by social learning alone; the capacities to learn from and modify our environments also play a significant role. (shrink)

August Weismann is famous for having argued against the inheritance of acquired characters. However, an analysis of his work indicates that Weismann always held that changes in external conditions, acting during development, were the necessary causes of variation in the hereditary material. For much of his career he held that acquired germ-plasm variation was inherited. An irony, which is in tension with much of the standard twentieth-century history of biology, thus exists – Weismann was not a Weismannian. I distinguish three (...) claims regarding the germ-plasm: (1) its continuity, (2) its morphological sequestration, and (3) its variational sequestration. With respect to changes in Weismann’s views on the cause of variation, I divide his career into four stages. For each stage I analyze his beliefs on the relative importance of changes in external conditions and sexual reproduction as causes of variation in the hereditary material. Weismann believed, and Weismannism denies, that variation, heredity, and development were deeply intertwined processes. This article is part of a larger project comparing commitments regarding variation during the latter half of the nineteenth century. (shrink)

Darwin’s ideas on variation, heredity, and development differ significantly from twentieth-century views. First, Darwin held that environmental changes, acting either on the reproductive organs or the body, were necessary to generate variation. Second, heredity was a developmental, not a transmissional, process; variation was a change in the developmental process of change. An analysis of Darwin’s elaboration and modification of these two positions from his early notebooks (1836–1844) to the last edition of the /Variation of Animals and Plants Under Domestication/ (1875) (...) complements previous Darwin scholarship on these issues. Included in this analysis is a description of the way Darwin employed the distinction between transmission and development, as well as the conceptual relationship he saw between heredity and variation. This paper is part of a larger project comparing commitments regarding variation during the latter half of the nineteenth century. (shrink)