The overall resemblance between Hume’s and Strawson’s strategy in dealing with issues of freedom and responsibility is striking. The fundamental point that they agree about is that we cannot understand the nature and conditions of moral responsibility without reference to the crucial role that moral sentiment plays in this sphere. This naturalistic approach places Hume and Strawson in similar positions when considered in relation to the views of the pessimist and the optimist. The naturalistic approach shows that, in different ways, both sides of the traditional debate fail to properly acknowledge the facts about moral sentiment. Where Hume most noticeably differs from Strawson, however, is on the question of the “general causes” of moral sentiment. Strawson largely bypasses this problem. For Hume, this is a crucial issue that must be settled to understand why necessity is essential to responsibility and why indifference is entirely incompatible with the effective operation of the mechanism that responsibility depends on.