 However, the view that species are individuals leaves other important questions about species unsolved and raises new problems of its own (Kitcher 1984, 1989). For example, suppose you are a population biologist and you need to census the individuals in a population of species. How do you decide what entities to count? Philosophers and biologists have provided a variety of criteria for answering questions like this including reproduction, life-cycles, genetics, sex, developmental bottlenecks, germ-soma separation, policing mechanisms, spatial boundaries or contiguity, immune response, fitness maximization, cooperation and/or conflict, codispersal, adaptations, metabolic autonomy, and functional integration (Clarke 2013). So, the question of what a biological individual is indeed a pressing one (Wilson 2005; Okasha 2006; Clarke 2011; Pradeu 2012; Bouchard and Huneman 2013; Clarke 2013; Godfrey-Smith 2013; Wilson and Barker 2013).