Human beings are affected by certain physical entities in their surroundings. These effects are internally experienced and perceived directly, without the mediation of conceptual frameworks. Some sense-data theorists in analytic philosophy—such as Bertrand Russell—have interpreted these effects as physical phenomena, concluding that humans can attain awareness of at least some physical entities (i.e., sensory experiences) without recourse to reason or universal concepts. On the other hand, logical positivists regard such awareness as the foundational basis for all knowledge of the external world. Consequently, they not only deny the role of reason and universal concepts in understanding physical reality, but also emphasize the meaninglessness of metaphysical propositions. According to this view, demonstrative reasoning in philosophical ontology must be abandoned, and the task of understanding existence should be entrusted solely to empirical sciences. This study, employing a descriptive-analytical method, first examines the nature of sensory experience and its distinction from sensual perception. It then briefly argues that sensory experiences are not physical in nature, and that direct awareness of physical entities is fundamentally unattainable. More importantly, regardless of whether sensory experience is material or immaterial, relying solely on such experiences—without the aid of reason, concepts, or mental inference—renders it impossible to affirm the existence of any physical reality beyond these impressions, let alone to treat them as the foundation for knowledge of any truth in the external world.