Humans often seek to improve themselves, whether through self-discipline or through the use of science and technology. At some point in the future, techniques might become available that will change humans to such a degree that they might have to be regarded as something other than human: posthuman. This essay tries to define the point at which such a human-to-posthuman metamorphosis may occur. This is achieved by discerning what is it that makes human substance distinct, i.e. what is the human (...) essence. This is accomplished by examining the features of the human body, looking at the mode of human existence in society and trying to grasp the importance of the body–soul relationship. Throughout the process, humans are compared to animals as well as entities from literature, film, and the gaming world. These are used as case studies to shape and test the ideas developed throughout the essay. This essay's conclusions might become useful when decisions will have to be made as to the legal status of posthumans,... (shrink)