But it is implausible that we can gain empirical knowledge of the external world this way, relying only on introspection and armchair reflection on externalism.
Russell in particular tried to show, in such works as The Problems of Philosophy (1912) and Our Knowledge of the External World (1914), that knowledge of the external world could be logically constructed out of sense-data.
A person who accepts this challenge will, in effect, be addressing the larger philosophical problem of our knowledge of the external world.
According to Husserl, the philosophies of Descartes and Kant presupposed a gap between the aspiring knower and what is known, one that made claims to knowledge of the external world dubious and in need of justification.
Thus, he held that it is illegitimate to assume that there is a problem about our knowledge of the external world prior to conducting a completely presuppositionless investigation of the matter.
In 1914, in Our Knowledge of the External World, Russell argued that the world is "constructed" out of sense-data, an idea that he refined in The Philosophy of Logical Atomism (1918 19).
The central themes in Hume's skeptical analysis the basis of induction and causality, knowledge of the external world and the self, proofs of the existence of God became the key issues of later philosophy.
In a work entitled Our Knowledge of the External World (1914), Russell analyzed the concept of physical objects as comprising classes of (perceptual) aspects or perspectives, an idea that later stimulated the work of Rudolf Carnap, an outstanding philosophical semanticist and analyst, entitled Der logische Aufbau der Welt (1928; The Logical Structure of the World).
Now I am not, however, supposing that all knowledge of the external world is inferential.
If all these conditions are satisfied, I have knowledge of the external world.
By itself, (A) has no implications for knowledge of the external world.
