Who to read in philosophy concerning knowledge and what exists?

I would read a dialectical philosopher. By this I mean a philosopher who has examined the claims and arguments of previous philosophers and has come to his own conclusions. If you had lived at any time up to the 16th century, you should and would have read Aristotle and his commentators, such as Aquinas, Maimonides, and Averroes. But after the discoveries of Galileo in the 17th century there occurred a scientific revolution in physics and astronomy culminating in the work of Newton. And the philosopher to read then was Locke in England, and Descartes in France. The former was an empiricist; the latter a rationalist, whose position was developed by Leibniz. And Hume had presented a major challenge to empiricism. Well, these two strands of empiricism and rationalism were critically examined and readjusted by Immanuel Kant. So, contemporary philosophy (i.e., epistemology and ontology) must now take into account Kant and any advances in science.

So, the question is: which author has competently taken into account this stream of philosophy? My first stab would be to read Bertrand Russell, especially his The History of Western Philosophy (1945). But a second, and an improved reading would be to read everything written by C. D. Broad. Why? Because Russell remained an empiricist, while Broad had absorbed Kant, while still critically having surveyed the history of philosophy. [See my: Philosophical Alternatives from C.D. Broad]

There is an outstanding philosopher — Wilfrid Sellars. [See my: Problems from Wilfrid Sellars] But I would not recommend reading Sellars to a novice because he is too technical. He assumes a knowledge of current technical philosophical literature. He can be appreciated only by professional philosophers. However, several books have now been published with the intention of making him more accessible to a wider audience. Wilfrid Sellars was trying to come to grips with Kantian themes, as have many other Kantian scholars.

One such outstanding Kantian scholar is Robert Paul Wolff, who published his findings in the book Kant’s Theory of Mental Activity (1963). His lectures on Kant, given in 2016, are available on youtube, and I recommend them. Here they are:

Lecture 1

Lecture 2

Lecture 3

Lecture 4

Lecture 5

Lecture 6

Lecture 7

Lecture 8

Lecture 9

As a caveat, I just want to point out that neither Sellars nor Wolff had available to them C. D. Broad’s book: Kant. The reason is that Broad had written out his Kant lectures in 1950-52, and this manuscript was only published by C. Lewy in 1978.

Also see: Kant and Building a Robot