Not even natural inclinations are always fully operating. For example, the mind of a sleeping man has the deep dispositional structure that normally enables him to consider the dependence of conclusions on premises, but because he is asleep, he cannot use it. In the same way, the mind of a small child has the deep dispositional structure that will one day enable him to grasp the general principles of the natural law, but because he has not yet reached the age of reason, he cannot correctly put them into action.
Yet isn’t it interesting that something is there even so? Even the smallest child knows that the force of “That’s not fair!” is greater than the force of “But I want!” He cannot reliably discern what is fair and unfair – but he grasps that there is a difference. No animal grasps that. We don’t have a tape measure long enough to measure the chasm between the silliest child and the wisest chimp.