Why did the verifiability principle face criticism from philosophers?

The verifiability principle, a cornerstone of Logical Positivism, faced significant criticism from philosophers primarily due to its own logical status and its inability to account for various types of meaningful statements.12

Key criticisms include:

• Self-Refutation: The most prominent critique is that the principle itself is neither empirically verifiable nor a tautology. Consequently, by its own criteria, the principle is rendered meaningless. Defenders have attempted to frame it as a recommendation for scientific inquiry or an arbitrary definition, but these responses have been widely debated.12
• Formulation Difficulties: Positivists struggled to create a consistent, precise definition of verifiability. Early, strict interpretations were too narrow, potentially dismissing scientific generalizations or historical claims as meaningless. Later, weaker formulations—such as those proposed by A.J. Ayer—often proved too broad, inadvertently allowing metaphysical statements to qualify as meaningful.2
• Underdetermination: Willard Van Orman Quine argued that individual sentences cannot be verified in isolation because any experience can be reconciled with a theory through adjustments elsewhere in the system, suggesting there is no singular "fact of the matter" regarding meaning.3