The philosopher David Hume had a very skeptical perspective on causality. Being an empiricist, Hume believed that all knowledge and perceptions were derived from our senses (i.e. sight, hearing, taste, touch, smell). Hume argued that it was impossible to witness causality, or the “idea that when one object causes another object to do something, there is some kind of real connection between them, some kind of “power” or force by which the cause really exerts its causality in its effect” (Velasquez 344). In other words, Hume believed that “events simply succeed each other”, and that there is no real connection (a cause and an effect) between two events (Velasquez 345). We simply perceive a “cause and effect” situation because we are habituated to the idea that “events of the first kind will be followed by events of the second kind” (Velasquez 345). In other words, Hume seemed to believe that events simply unfold and that there is no causality between them.
A person who is determined to defend the cause and effect scenario would probably respond to Hume’s view in a manner similar to Immanuel Kant. Kant’s epistemological beliefs were a mix of empiricism and rationalism; he believed that we experience the world through our senses, but that our mind organizes these senses in a rational way to construct the world that we perceive.
Kant believed that our mind was a “unified awareness”, or that our minds require unity in order to perceive the world. The sensory information that we perceive is rationally constructed by our mind, and since it is constructed in a “unified” way, that would mean that our minds are a “unified awareness”. The mind “connects and unifies its sensations into a unified world of interrelated objects because it must” (Velasquez 357). So, since our perceptions of the world rely on “unity”, that would mean “cause and effect” exists, because causality shows that every event is ultimately connected. In other words, causality states that every event must have a cause, and this would mean that every action in our universe is somehow connected to another action or event. This “connection” implies some sort of “unity”, and since our minds are a “unified awareness”, it would mean that causality exists (at least in the mind) because it unifies the world around us. Hume’s anti-causality view seemed to imply that there is no “unity” in the world – that things simply happen with no “force” connecting one event to another. This is different from Kant, who believed that there must be some kind of cause and effect relationship present because this relationship explains how our mind constructs the world around us.
Kant believed that our mind uses causality to determine change that is independent of ourselves. So, “if the changes of objects in the world were not caused by other objects in the world… I would not be able to tell the difference between changes of objects in the world and changes I produce” (Velasquez 357). Basically, Kant is saying that causality exists because we can determine what changes are caused by us and what changes are not caused by us (i.e. changes that are independent of our actions). If causality did not exist (as Hume believed) then we would be unable to tell the difference between the changes we cause and the changes we do not cause. However, since we can distinguish between the two, that would mean that cause and effect does exist.