A very different response to Hegel (and Kant) is found in the work of Søren Kierkegaard (1813–55), a religious thinker who started, like Hegel and Kant, from Lutheranism. Kierkegaard mocked Hegel constantly for presuming to understand the whole system in which human history is embedded, while still being located in a particular small part of it. On the other hand, he used Hegelian categories of thought himself, especially in his idea of the aesthetic life, the ethical life and the religious life