“In terms of your own personality or the personality of all people, you must not use human nature only as a means, but always use it as an end in itself.” Kant believes that the essence of human beings lies in human beings. Reason, rational people are the purpose of existence. Other existences in the world, whether living or non-living things, should serve this "purpose" and can be called "tools" and "means". Only rational people are the masters and users of tools, not the tools themselves.