This chapter considers a serious challenge to conceptual realist readings of Hegel which is based on his Philosophy of Nature. According to such readings, one way in which reason is inherent in the world rather than imposed upon it is that individuals are instantiations of substance universals such as “horse” or “human being” which we come to know, and which belong essentially to those individuals in their own right. However, critics of this conceptual realist reading have then countered that in his philosophy of nature, Hegel speaks about the “feebleness of the concept in nature” and seems to allow for a good deal of indeterminacy in the way individuals are classified into kinds, making it hard to see them as essential to individuals and as inherent to the world in the way the conceptual realist claims. This debate and how it relates to Hegel’s Philosophy of Nature is then the focus of this chapter. It is argued that nothing in what Hegel says about the problems in classifying nature in fact threatens conceptual realism, thereby showing how the conceptual realist reading can be vindicated in a way that is consistent with this text.