‘What is to be Done? How to respond to nihilism’ asks: how is freedom to take effect in the world of nature, if the latter is governed by causality and mechanistically determined by the laws of nature? The recognition of the subject's freedom goes hand in hand with the collapse of moral certainty in the world. Nietzschean nihilism is examined and German nihilism distinguished from Russian. The problem of philosophical modernity is how to confront the problem of nihilism after one has seen how the values of Enlightenment not only fail to get a grip on everyday life, but lead instead to its progressive dissolution.