 Martin Luther (1483–1546) is the central figure of the Protestant Reformation. Whilst he is primarily seen as a theologian, the philosophical interest and impact of his ideas is also significant, so that he arguably deserves to be ranked as highly within philosophy as other theologians in the Christian tradition, such as Augustine or Aquinas. Nonetheless, in Luther’s case this may seem more problematic, as his attitude to philosophy and indeed reason can be hostile and dismissive. On closer inspection, however, it is clear that his position is more nuanced than that, and requires contextualisation: for his objection is only to reason put to certain theological ends, while his own thought is deeply steeped in the philosophical tradition, and contributed to it. At the same time, Luther’s ideas had a fundamental influence on northern European philosophers who came after him, such as Leibniz, Kant, Hegel, Schelling, Kierkegaard, Nietzsche, Feuerbach, and Heidegger, all of whom worked within a broadly Lutheran context, and against the background of central Lutheran assumptions, often inculcated in them through their upbringing and  education.[1]