David Hume's Critique of Causality: Impact on Philosophy

David Hume

His Impact on Philosophy and the Critique of Causality

David Hume (1711-1776) is one of the most influential philosophers, and exerted a profound impact on Immanuel Kant. Among the most important aspects of his philosophy is his criticism of the principle of causality.

Limitations of Knowledge and Future Events

According to Hume, our knowledge of facts is limited to current and past impressions. We cannot have knowledge of future events because we cannot have impressions of an event that has not yet happened. However, in our daily lives, we constantly assume that certain events will occur in the future. For example, we place a container of water on the fire, expecting it to heat up. But if we initially only feel cold water over the flame, how can we be sure that we will later feel hot water?

Causal Inference and the Idea of Cause

Hume noted that in these cases, our certainty about what will happen in the future is based on a causal inference: we are sure that the water will heat up because we believe that fire produces this effect. The idea of cause is at the core of all our inferences about facts for which we do not have current evidence.

The Necessary Connection Between Cause and Effect

Hume observed that the cause-effect relationship is usually conceived as a necessary connection: fire necessarily heats water; therefore, if we place water on the fire, it will necessarily be heated. Since such a connection is deemed necessary, we believe we can know with certainty that the effect will occur.

Hume's Criterion of Truth and the Absence of Necessary Connection

For Hume, the criterion of truth is whether an idea corresponds to an impression. Since we cannot have impressions of the future, and we have no impression of a necessary connection between the fire that warms and the water that boils, we can only observe a constant succession between one phenomenon and another. We have no direct experience that a second incident was caused by the first. Therefore, our understanding of the future is not knowledge but belief or supposition; the supposed certainty comes from habit.

Hume's Conclusions on Causality

Therefore, according to Hume:

• We cannot affirm the principle of causality because our impressions are of the past, not the future, and we have no impressions of a required causality.
• There is a succession of impressions, but no cause and effect; in this case, it is a mere sequence.
• From an impression, we cannot deduce something for which we have no impression.