Hume makes a distinction between relation of ideas and matter of fact. Relation of ideas is a priori, meaning that it can be justified by reason. It does not depend on something else that exists in the universe. Denying, or trying to falsify the propositions is a contradiction or inconceivable. People gain this knowledge intuitively, or through demonstrative reasoning. Matters of fact are posteriori in that they are only justified through experience. They are possible, but they may not be necessary, and it is consequently necessary to deny them without contradiction.
Denying such propositions is conceivable. People know and understand this knowledge through cause and effect, and this is based on their experiences; accordingly, it is not possible to demonstrate it. This makes it possible to infer an unobserved fact from an observed one. Since there is no contradiction made in denying matters of fact, then one cannot justify a causal inference. People are able to tell what will happen in the future because of what they have observed in the past.
Reasoning by induction is based and justified on a universal principle, which explains with certainty that the future will resemble the past. It is not possible to determine a universal principle, through reason since denying such a reason would be possible and conceivable. Hume, further points out that reasoning by induction is not valid because of the impossibility of proving a universal principle. People’s acceptance of a universal principle is not rational since they have no reason for doing something in their own way, and not in another way.
It is possible to get the intended results, but the results can also fail. People’s acceptance of a universal principle is based on customs rather than reason.
There are two parts of the dilemma. If determinism is true, then there is no free will. If there is indeterminism, then there is no control of will, and consequently, no control of action. Determinism is the idea that all events are caused, and, as a result, there is no free will since all actions are pre determined. Determinists believe that having free will means acknowledging the idea of a supernatural. The existence of a supernatural enables them to make conscious decisions, and this separates them from the other natural world. This limits people in the decisions they make. A person who is worried and conscious about the alternative he chooses does not have free will when making that decision. Compatibilism posits that it is possible to have determinism and free will. Incompatibilism rejects the idea of free will in determinism. Compatibilism rejects the idea of someone or an agent determining a person’s actions because if this were the case, then there would be no free will. Some compatibilists believe that a free willed action is one that a person does out of his own decision, without any force or compulsion from someone. The definition of free will or freedom is the main determinant in understanding compatibilism in such a case. Such compatibilists believe that freedom is lack of constraints by forces, which are beyond someone’s control. In such a case then, the person has both free will and determinism.
Libertarians are incompatibilists, in that they do not believe that free will and determinism are compatible. They recognize that there may be some constraints limiting people’s actions, but these constraints do not determine people’s actions. People are rational and they are capable of choosing one choice from the possible alternatives freely. Compatibilism recognizes the presence of determinism, which in essence hinders free will. Libertarianism advocates the idea of people being free. Actions are free if they originate from the agent, and if there are alternatives. This gives the agent the freedom of the mind, in terms of the actions thought of and the freedom to choose from the alternatives. Agent-causation means that the agent has free will in determining the cause of the action. This differs from event causation, whereby the agent does not have any free will. A chain of caused events begins with the agents, and the agents do not act in response to the event, which would signify them having limited options.