Hume turns his considerations of necessary connection toward the topic "Of Liberty and Necessity," the title of section VIII. He suggests that the debate and controversy regarding free will and determinism is simply a matter of the disputants not having properly defined their terms. In fact, he asserts, all people would find themselves of the same opinion on this subject if only they were more careful in their definitions.
Hume begins by examining what we call necessity in physical processes. We are apt to suppose that there are laws in nature that determine the necessary forces, causes, and effects that determine the movements of all bodies without exception. However, as Hume has discussed, our ideas of necessary connection and causation result only from the observation of constant conjunction between events and a certain determination of our minds. We infer the idea of necessary connection, but nowhere observe it directly in nature.
Next, Hume considers human nature and the laws that govern our behavior. Similarly, he finds that throughout history and across cultures our behavior remains relatively constant. Similar motives produce similar actions and similar causes produce similar events. What we call "human nature" springs from a certain regularity that we observe in human behavior in all sorts of circumstances.
If we observe a physical phenomenon that runs counter to our expectations, we will not suppose that the laws of physics have been suspended, but simply that some unobserved and contrary force must also have been acting that upset our predictions. Hume suggests that we might similarly explain the unexpected behavior of people. Rather than perceive them acting at random, we might suppose that there is some hidden motive or unknown personality trait that makes them act contrary to our expectations.
Thus, people, just as much as physical objects, can be understood to behave in accordance with strict laws and principles that we might claim to understand. Everyone would agree that we predict and infer regarding human behavior based on certain observed regularities just as much as we do with dead matter. Our entire behavior is directed by certain expectations of the behavior of others so that, for instance, the farmer would not work the land and put his crops up for sale if he did not expect other people to pay a fair price for them.
Hume suggests that any opposition to this view has sprung from the false supposition that we can perceive necessary connections in nature. Our inferences regarding human nature are based solely on the observation of constant conjunction, and we would strongly deny that any kind of necessity governs our actions. However, if we grant that we observe no necessary connection governing physical phenomena either, we might see that our predictions of human behavior and physical behavior reduce to a similar set of observations. Necessary connection, be it in matter or in human behavior, is not found in the object itself, but in the imagination of the observer.