Given that Wikipedia is down today, in protest at the United States' 'Stop Online Piracy' and 'Protect Intellectual Property' Bills, I turn to the Stamford Encyclopedia of Philosophy:
"Defined narrowly, epistemology is the study of knowledge and justified belief. As the study of knowledge, epistemology is concerned with the following questions: What are the necessary and sufficient conditions of knowledge? What are its sources? What is its structure, and what are its limits? As the study of justified belief, epistemology aims to answer questions such as: How we are to understand the concept of justification? What makes justified beliefs justified? Is justification internal or external to one's own mind? Understood more broadly, epistemology is about issues having to do with the creation and dissemination of knowledge in particular areas of inquiry."
Andrew Seth argues in Britannica that there is frequently confusion between psychology and the theory of knowledge. Immanuel Kant (1724-1804) is credited with first clearly making the distinction between the two, repeatedly insisting that his Critique of Pure Reason was not to be taken as a psychological enquiry. He defined his problem as the quid juris or the question of the validity of knowledge, not its quid facti, or the laws of the empirical genesis and evolution of intellection.
Britannica has a wonderful paragraph which brings this all together as follows:
"Appearing thus, first, as the problem of perception (in Locke and his English successors), widening its scope and becoming, in Kant's hands, the question of the possibility of experience in general, epistemology may be said to have passed with Hegel into a completely articulated "logic," that claimed to be at the same time a metaphysic, or an ultimate expression of the nature of the real. This introduces us to the second part of the question we are seeking to determine, namely, the relation of epistemology to metaphysics".
"These are ultimately two sides of the same enquiry. But it is not every thinker that can see his way with Hegel to assert in set terms the identity of thought and being. Hence the theory of knowledge becomes with some a theory of human ignorance."
I think this brings us neatly back to Wittgenstein.
Now I move on to æsthetics, which, according to Britannica may be treated as a department of psychology or physiology, which is the most frequent mode of treatment in England.
To what peculiar excitation of our bodily or mental organism, it is asked, are the emotions due which make us declare an object beautiful or sublime?
- A mere reference of these emotions to the mechanism and interactive play of our faculties cannot be regarded as an account of the nature of the beautiful
- In the case of a beautiful object, the resultant pleasure borrows its specific quality from the presence of determinations essentially intellectual in their nature, though not reducible to the categories of science
- We have a prima facie right, therefore, to treat beauty as an objective determination of things
- The question of æsthetics would then be formulated - What is it in things that make them beautiful, and what is the relation of this aspect of the universe to its ultimate nature, as that is expounded in metaphysics
The remaining sections of the Britannica article which I have not commented on relate to ethics, or moral philosophy as it tends to be referred to in modern times. There is clearly a huge amount of thinking to be done on moral questions such as what is good, the principle of duty, the issue of free will and ultimately the laws of morality. I am very much looking forward to exploring these questions.
You may want to check out the excellent video series 'Justice' recorded at Harvard University with Michael Sandel for an introduction to some of the questions addressed by moral philosophy.