It seems to me that you have at least three classes of judgement in your question. 1. Prejudice. 2. Common Sense. 3. Informal definitions. 4. Inductive generalisation. Let's start with the latter: if all the Xs I have come across are Ys, and if I have no reason to believe that the Xs I have come across are exceptional or otherwise not representative, then I have some confidence that Xs are Ys. Americans are foolish. What I am calling an informal definition is a way of describing an identifying feature of something: dogs have four paws. Now, this is different from the above because you very likely learned about dogs in part by having the number of paws pointed out to you, whereas probably you didn't learn what an American is by having their foolishness pointed out. Continuing backwards, I would claim that the first two categories have something social or cultural about them, that the second two do not necessarily have. Common sense is called 'common' to indicate that it belongs to a particular social...

There is certainly something of Hume's reasoning in your question (see the end of section v of the first Enquiry ). And, this way of thinking about knowledge becomes a basic definition of knowledge in pragmatism (Pierce, James et al). However, it is inappropriate in Kant. We must take what you term the categorical difference between things-in-themselves and appearances seriously. Appearances are the only domain of knowledge. This is not because appearances are what we are directly acquainted with, while things-in-themselves are in some way hidden. If that were the case, as you say, there would be good reason to think that the former would have to be correlated with the latter, and that through this correlation, the latter could come to be known. Rather, we should say that the thing-in-itself is such as to not be a possible object of knowledge. In other words, whatever forms of knowledge would be necessary to know a thing-in-itself (even talking about a 'form of knowledge' here is probably already...

'Bias' here might mean 'a distortion of thought caused by the nature of thought being something essentially different from what is thought about'. This notion of bias is discussed in Professor Lipton's answer above. However, a related but not identical definition of 'bias' is 'preconceptions; or thoughts that in some way "colour" my presentations of the world'. Thus, we might accuse a judge in a court case of being ‘biased’ if we believe they have preconceptions (attitudes that are in place prior to hearing the specific evidence in the case) about the guilt or innocence of the defendant. Similarly, a political reporter would be ‘biased’ if their existing political beliefs influenced their reporting. In this case, not being biased would mean being objective. Now, it is difficult to be objective in this way, to be sure; also, we might claim that striving for such impartiality is something like a duty for judges and reporters. However, consider the following admittedly extreme case. I am a...

Consider the following quotation from Kant: There can be no doubt that all our knowledge begins with experience. […] [I]t does not follow that it all arises out of experience . ( Critique of Pure Reason , B1) The point being made is that, of course, your unfortunate child would have nothing to think about without sensory input. But nevertheless, given experience, it may be that the mind makes an a priori contribution to that experience. By the way, I must disagree slightly with my colleagues writing below, at least as far as the interpretation of Kant . From the point of view of Kant, the justification account in Frege oversimplifies matters. This for three reasons. First, because on Kant's analysis there must be at least two distinct a priori grounds, neither of which can ground the other (sensibility and understanding). Thus, for Kant, we must not conflate the distinctions a priori/ a posteriori and analytic/ synthetic. Second, because an analysis of these grounds...

It is worth noting that Descartes' version of this problem is made all the more difficult by the fact that thinking-substance and material-substance were considered to be of radically different types. Accordingly, it is not just the case that access to my thought, and proof of my existence as a mind, are accidentally in the first person, but necessarily so. Thought is not the kind of property that a material object could exhibit. From this is also follows that if a material object does exhibit clear signs of rational thought, then it could not but contain a mind. If Descartes is able to observe in himself actions of the body that necessarily depend upon thought, he could then looks for such actions in other bodies and thus prove other minds. The problem is proving the necessity of the dependence relation. However, this notion of two distinct types of substance is by no means universally accepted! If, in some way, thought were a feature of our bodies (of a physical brain, say), then the...