 As in Parmenides’ account of thought as a “mixture of much-wandering limbs” (B 16 = D 51), so too in Empedocles thinking appears to result from the blended ratio (Palmer 2019)—in this case, of the mixture of earth, water, air, and fire (A 86 = D 237). It has been suggested that the roughly even distribution of the four elements in blood is what makes it so suited to cognition (Long 1966). Though both cognition and sense perception operate on the basis of affinity, their relationship to one another is less clear. According to the traditional interpretation, cognition does not seem to rely upon the senses. Nor is there a single “command center” in the blood around the heart, where effluences from the sensory organs are relayed to. Instead, cognition operates as a sense in its own right. This materialist account of cognition has lately been called into question (Curd 2016). As Empedocles is committed to the idea that all things have a share of thought (B 110 = D 257), then this must include things that have no blood. For humans, pericardial blood might then serve as a command center for sensory data, for evaluation and judgment.