A priori and a posteriori

Philosophical concepts related to knowledge and justification

A priori and a posteriori are two fundamental concepts in epistemology, the branch of philosophy concerned with the nature and scope of knowledge. These terms are used to distinguish between types of knowledge, justification, or arguments based on their sources and methods of acquisition.

Definitions

A priori

The term a priori is Latin for "from the earlier." It refers to knowledge that is independent of experience. A priori knowledge is typically associated with reason and logic, and it is considered to be universally true. Examples of a priori knowledge include mathematical truths, such as "2 + 2 = 4," and logical propositions, such as "all bachelors are unmarried."

A priori knowledge is often contrasted with empirical knowledge, which is derived from sensory experience. Philosophers such as Immanuel Kant have argued that a priori knowledge is necessary for making sense of experience, as it provides the framework within which empirical knowledge is organized.

A posteriori

The term a posteriori is Latin for "from the latter." It refers to knowledge that is dependent on experience or empirical evidence. A posteriori knowledge is acquired through observation and experimentation. For example, the knowledge that "the sky is blue" or "water boils at 100°C at sea level" is a posteriori, as it is based on sensory experience and empirical investigation.

A posteriori knowledge is often associated with the scientific method, which relies on observation, experimentation, and evidence to form conclusions about the natural world.

Philosophical Significance

The distinction between a priori and a posteriori knowledge is significant in philosophy because it addresses the sources and justification of knowledge. This distinction is central to debates about the nature of truth, justification, and the limits of human understanding.

Kant's Contribution

Immanuel Kant was a pivotal figure in the discussion of a priori and a posteriori knowledge. In his "Critique of Pure Reason," Kant proposed that while all knowledge begins with experience, not all knowledge arises from experience. He introduced the concept of "synthetic a priori" knowledge, which refers to propositions that are universally true and necessary, yet not derived from experience. An example of synthetic a priori knowledge is the statement "every event has a cause."

Contemporary Views

In contemporary philosophy, the distinction between a priori and a posteriori knowledge continues to be a topic of debate. Some philosophers argue that the line between the two is not as clear-cut as traditionally thought, and that there may be a continuum between purely a priori and purely a posteriori knowledge.

Also see

• Epistemology
• Immanuel Kant
• Rationalism
• Empiricism
• Synthetic a priori
• Analytic-synthetic distinction

References

• Kant, Immanuel. Critique of Pure Reason.
• Audi, Robert. Epistemology: A Contemporary Introduction to the Theory of Knowledge.
• BonJour, Laurence. In Defense of Pure Reason.