Who's afraid of epigenetics? Habitual processes, epigenetic mechanisms and their role in heredity (from Charles Darwin to the contemporary debate)

Although, throughout the history of the discipline, philosophers have regularly turned to the concept of "habit" in order to understand a broad range of issues from ethics to psychology to the philosophy of mind, the last decades have witnessed a special growth of interdisciplinary interest in habits, which have become an object of research for neuroscientists, cognitive scientists, developmental psychologists, sociologists, anthropologists. It is known that Charles Darwin, first major proponent of biological evolution by means of natural selection, devoted much attention to habits (and to the strictly related notion of "instinct") in his juvenile Notebooks and, although from a slightly different theoretical perspective, also in his more mature works. Darwin develops an idea of experience as a process of habit formation, both at the individual and at the collective level; in his juvenile Notebooks, he pivots on the notion of "habit" in order to understand how an organism's morphology and behaviour can be changed and moulded through the interaction with its physical and social environment, and how these acquired changes can be transmitted to the offspring. He suggests that learnt behaviour that becomes habitual eventually becomes hereditary. Today's evolutionary theory is obviously a much more sophisticated research paradigm than the theory that first emerged from Darwin's own writings in the second half of the nineteenth century. However, some recent research, particularly in the field of biological inheritance mechanisms, seem to lead us right back to Darwin's key ideas on habits. As the geneticist and molecular biologist Eva Jablonka has written, today's theories of inheritance, and more specifically epigenetic theories (which investigate the way in which the functioning and expression of genes is modified by the environment, and how these modifications are transmitted over generations) can shed new light on Darwin's theory of habits and instincts. What is the relationship between habitual processes and epigenetics processes? What role do habitual or epigenetic processes play in heredity? What role have habits and instincts played in the first formulation and in the further developments of Darwin's theory of evolution? The aim of the present paper is twofold: first, we intend to outline and examine Charles Darwin's views on habits and instincts and his idea of human experience as a process of habit formation, by referring not only to his juvenile writings but also to his more mature works; second, we intend to provide an overview of the most recent results in the field of epigenetics and to briefly describe the state-of-the-art in the discipline with particular reference to the trans-generational transmission of epigenetic modifications. Although empirical studies on human epigenetics are still in their infancy and, at this stage, non-human animal studies are the most effective means of understanding genes regulation, we suggest that epigenetics can provide some intriguing conceptual tools to look at human behaviour from a new perspective, focusing on the notion of habit and overcoming the (largely detrimental) nature/culture dichotomy.