In this post I will try to explain why a taxonomy would be useful. In brief: there are different kinds of seemings, and we have different, non-equivalent, ways of ascribing seemings to subjects. Thus philosophers need to be careful when and how they use ‘seem’ to make sure that their arguments do not equivocate and that they do not talk past each other. Providing a taxonomy of seemings can help us to avoid these problems.
In everyday speech it is common to talk about some of our mental states by using ‘seem’: the stick half in water, for example, seems bent to me, and it seems that this winter will be colder than last winter. Philosophers also talk about seemings. Indrek Reiland (2014) appeals to seemings to resolve the debate over whether we perceptually experience 'high-level' properties (e.g. tigerness, friendliness) as well as 'low-level' properties (redness, squareness). George Bealer (1998) appeals to seemings to explain what intuitions are: they are intellectual seemings. And the papers in Chris Tucker's collection (2013) consider whether appealing to seemings can give us (defeasible) justification for some of our beliefs. It is tempting, then, to think that there is one kind of mental state—seeming—which is relevant to intuitions, justification, and perception.
Seemings, however, do not form a unified kind. As Roderick Chisholm (1957) pointed out epistemic seemings concern how we take the world to be (whether on the basis of perception or not). Thus, if I read in the paper that Hilary Clinton has been involved in some terrible scandal, it might seem to me that she will not be the Democratic presidential candidate in the next election. When it comes to epistemic seemings, it cannot be that it seems to me that p, but I do not believe that p (at least not if I am rational). With non-epistemic uses of seems, however, it can seem to me that p even though I know that not-p. For example, there are perceptual non-epistemic seemings: when I look at the Müller-Lyer illusion, it seems to me that the lines are of different lengths, even though I know they are not. And there are intellectual non-epistemic seemings: it can seem to me that a certain proof is valid—the truth of each statement seems guaranteed by that of those which precede it—even though I know that last month I was able to show that the proof was not valid (but now I cannot remember how).
The way we ascribe seemings complicates matters. Usually, ‘O seems F to S’ is true just when ‘it seems to S that O is F’. But this is not always so. Imagine that I have never heard of the British actress Keira Knightley. I see her being interviewed on TV and I mistakenly think I am seeing the American-Israeli actress Natalie Portman being interviewed (the actresses look similar). As I watch, it seems to me that Portman has a British accent. But it is not true that Portman seems to me to have a British accent—it is Knightley who seems to me to have a British accent (although I do not realise this).
So it seems (!) that there are different kinds of seemings, and different ways we can ascribe seemings to subjects. Establishing how these kinds are related, and what connects the methods of ascription, should shed light on what seemings are, and how they are relevant to perception, justification, and intuitions.