Final answer:
Phenomenalism in analytic philosophy fell out of favour due to the critique of Logical Positivism's narrow theory of meaning, the anachronistic judgment of past philosophers, and the rise of perspectives that view knowledge as socially contextual rather than based on absolute facts.
Step-by-step explanation:
Phenomenalism, which was once a prominent theory in analytic philosophy, fell out of favor for several reasons. As the mid-20th century saw changing attitudes towards religion among philosophers, Logical Positivism, which underpinned phenomenalist thinking, was critiqued for its narrow theory of meaning. Logical Positivists' dismissal of religious language as meaningless was a direct result of their specific views on language, meaning, and their relation to observation and experience. This was part of a broader shift in analytic philosophy that turned away from linguistic analysis, which had posited that philosophical problems were mostly issues of language that could be clarified as such.
Furthermore, the exclusive focus on arguments within Logical Positivism came under criticism for overlooking the historical and cultural contexts of philosophical ideas. This led to the criticism of past philosophers by contemporary standards—an anachronistic approach that did not do justice to their works and intentions. In addition, the ahistorical understanding of philosophy's development ignored the fact that many philosophers, throughout history, held religious beliefs and were interested in or influenced by religion.
The advance of scientific methodology and rejection of a priori reasoning also contributed to shifts in philosophical thought. Thinkers began to see knowledge not as absolute facts but as shaped by social structures and contexts, as suggested by schools of thought like phenomenology and hermeneutics. These shifts in perspective challenged the basis of phenomenalism and contributed to its decline in popularity within analytic philosophy.