The central goals of enquiry are to discover what the world is like and how we ought to live. A simple and initially attractive picture is that there is a world independent of us that we can learn about via experience, and via reasoning. But both parts of this picture are subject to significant philosophical worries. Is the world truly independent of us, or do we somehow construct it – are truths about beauty and ethics, race and gender, dependent on our beliefs and relative to our perspectives? Does the existence of widespread disagreement in these areas show that there is no independent fact of the matter? Can we really know about a world independent of us given that we are subject to error and illusion, and that we can doubt all of our beliefs? Are there some truths that can’t be known or that can’t be known by certain groups of people?