Philipp Mainländer dedicated an essay to the philosophy of Von Hartmann. He did not consider him to be a genuine philosopher, because he did not start his philosophy with an epistemological research, despite the warnings of Kant and Schopenhauer. The criticism has been described as an attack abounding in clean hits but marred by bitter sarcasm, such as "is the coitus a "sacrifice" the individual makes? You must be – I repeat it – a very strangely organized being", and for denying Schopenhauer's deduction that the will is thing in itself: "you also have the sad honor, to stand at the same level as those who have misunderstood Copernicus and still confidently believe that the sun turns around the earth."