 Even for philosophers who are not philosophers of science, microbiology can be brought to bear on issues such as identity, selfhood, human nature, and mind, to generate broader insights and surprising conclusions. Not all such conclusions are defensible, but examining the ways in which microbes might contribute to humanness could be a valuable exercise. Consider why, for example, trillions of microbes living inside human bodies seem more easily regarded as part of that body, whereas the handful of helminths that do likewise are usually (but not always) distinguished as separate and ideally evicted. Microbes also offer philosophers tractable ways to study big questions about the nature of life, causation, and representation in general. For example, microbial experimental systems may be seen as material equivalents of the mental structures philosophers manipulate in thought experiments. There is also something to learn about the ways microbial and other modelling activities differ.