  Along these lines, the early modern concepts of subjectivity and self-consciousness added new elements to the definition and understanding of the central concept in personalism, or even substantially altered it. Immanuel Kant’s epistemic dualism, underscoring the importance of both subject and object in knowledge, opened the door both to the idealistic form of personalism and to the phenomenology and existentialism that became so important for twentieth-century personalism. Kant also contributed significantly to the personalist understanding of human dignity. Unlike Hobbes, for whom “the worth of a man” is “his price,” and dignity is “the publique worth of a man,” Kant regarded dignity as “intrinsic worth”. He posited a dichotomy between price and dignity, whereby “something that has a price can be exchanged for something else of equal value; whereas that which exceeds all price and therefore admits of no equivalent, has a dignity.” His celebrated practical categorical imperative – Act so as to treat humanity, whether in your own person or in that of another, always as an end and never as a means only – was incorporated nearly verbatim into Karol Wojtyła’s “personalist principle.”