 Theophrastus applies the diaeretic method in his treatise De Sensibus. The chief division—already found in corresponding passages in Aristotle—is between those who posit that knowledge is to be ascribed to similarity (‘like knows like’) and those who posit that it is to be ascribed to contrast (‘unlike knows unlike’). Another division, not paralleled in Aristotle, also plays an important part in classifying and dialectically discussing the tenets, viz. between those who assume that there is a difference between thinking and sense-perception, and those who do not. Finally, within each class the philosophers are treated in a sequence determined by the number of senses that are posited (category of quantity). The last philosopher to be discussed is Democritus, not Plato. This is because Democritus according to Theophrastus assumes that knowledge comes about through both similarity and contrast.