Why does Occam’s razor not prove that a simple theory is true?

Occam’s razor does not prove that a simple theory is true because it is a guiding heuristic rather than a principle of absolute truth. While the principle suggests that a simpler explanation is generally preferred when all other factors are equal, simplicity itself does not guarantee accuracy.1

The validity of the principle is often debated for several reasons:

• Subjectivity: Simplicity can be interpreted in multiple ways, such as syntactic simplicity (the elegance or conciseness of a theory) versus ontological parsimony (the number of entities a theory assumes). These different interpretations can lead to competing conclusions, making the principle difficult to apply consistently.1
• Risk of Inaccuracy: Prioritizing simplicity can lead to the sacrifice of accuracy. In complex fields like medicine or theoretical physics, relying solely on the simplest explanation can result in errors, such as misdiagnoses or the oversimplification of natural phenomena.1
• Contextual Limitations: Because the principle can lack firmness when applied to complex ideas, it is viewed by modern academics as a tool for reasoning rather than a definitive proof of reality.1

Ultimately, while William of Ockham employed this principle to sharpen philosophical inquiry, it remains a method for evaluating competing hypotheses rather than a mechanism for establishing objective truth.12