We've just examined the conditions that must be met for us to be held responsible – in perpetuity – for our actions. But to give a complete account of moral responsibility, we must also consider the nature of the authority to which we're accountable. To be responsible, we must have a rule to which we try to conform, in terms of which our responsibility is measured. In other words, we must be subject to some law, which is a moral rather than a psychological condition.

Let's examine the characteristics of this law. Philosophers generally agree that the moral law has three characteristics – it must be absolute, universal, and obligatory:

1. Absolute. There can be no exceptions to the moral law. Its commands must be relative, not to this or that individual, but to humanity as a whole. Moreover, the moral law can't be relative to this or that end. Its commands apply in every circumstance.

2. Universal. Here we face a difficulty, for some say that the moral law isn't the same everywhere. For example, there's a significant difference between the law of the savage and that of civilized man, suggesting that the moral law isn't universal. But all this objection really shows is that the material of the moral law varies – not the law itself. It's true that, when different peoples try to define the moral law, their mutual understanding breaks down. But they're still searching for a universal law. The savage considers his morality to be that of all peoples, so the facts particular to his circumstances don't contradict the universality of the moral law.

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