Final answer:
The question explores the nature of human knowledge concerning our inner experiences and the external world, as presented by Kant and Russell, considering the limitations of our cognition and the structure of knowledge. The discussion touches on categories of understanding, knowledge by acquaintance, and propositional knowledge, along with skepticism and the conditions for true knowledge.
Step-by-step explanation:
The argument presented is centered on the nature of human knowledge concerning the external world and our inner experiences, with reference to the works of philosophers like Immanuel Kant and Bertrand Russell. Kant argues that humans can never truly know things as they are in themselves (noumena) because our brains structure our experiences in a particular way, which is influenced by categories of understanding. This means that all knowledge of the external world (phenomena) is shaped by this structure, leading us to only ever perceive the world through the 'colored glasses' of our own conceptual framework.
Russell introduces the distinction between knowledge by acquaintance (direct, non-inferential knowledge of our own sensations) and propositional knowledge (knowledge of the truth of propositions about the world), claiming that even our most basic perceptions involve some level of inference.
The argument seeks to understand whether the awareness of one's will can be considered a form of experiencing appearances or whether it provides knowledge of the noumenon, which would imply direct insight into the nature of reality unaffected by our perceptual and categorical filters. Contemporary discussions of this topic often refer to skeptical arguments, like the 'brain in a vat' scenario or Gettier cases, which challenge our traditional notions of knowledge and justification, pushing philosophical inquiry to explore the conditions under which true knowledge is attainable.