A reader who says he is drawn to the view that knowledge excludes belief comments:
I am taking a philosophy class now that takes for granted that knowledge entails belief. My sense is that most philosophers now think that that condition is obvious and settled. They tend to dispute what "justification" means, or add more conditions to the Justified True Belief formula.
That knowledge is justified true belief is a piece of epistemological boilerplate that has its origin in Plato's Theaetetus. The JTB analysis is extremely plausible. It is first of all self-evident that there is no false knowledge. So, necessarily, if S knows that p, then 'p' is true. It also seems obvious that one can have a true belief without having knowledge. Suppose I believe that at this very moment Peter (who is 60 miles away) is teaching a class on the philosophy of science, and suppose it is true that at this very moment he is teaching such a class; it doesn't follow that I know that he is teaching such a class. Knowledge requires justification, whatever exactly that is. Finally, if S knows that p, how can it fail to be the case that S believes that p? It may seem obvious that knowledge entails belief. Necessarily, whatever I know I believe, though not conversely.
So I agree with my reader that most philosophers now think that the belief condition is "obvious and settled." But most academic philosophers are fashionistas: they follow the trends, stick to what's 'cool,' and turn up their noses at what they deem politically incorrect. And they read only the 'approved' journals and books. I pronounce my 'anathema' upon them. In any case it is not obvious that knowledge entails belief.
The Case for Saying that Knowledge Excludes Belief
Why not say this: Necessarily, if S knows that p, then it is not the case that S believes that p?
One cannot understand belief except in relation to other mental states. So let's consider how believing and knowing are related, taking both as propositional attitudes. They are obviously different, and yet they share a common element. Suppose we say that what is common to S's knowing that p and S's believing that p is S's acceptance of p. I cannot (occurrently) believe that Oswald acted alone unless I accept the proposition that Oswald acted alone, and I cannot (occurrently) know that he acted alone with accepting the very same proposition. To accept, of course, is to accept-as-true. It is equally obvious that what is accepted-as-true might not be true. Those who accept that the earth is flat accept-as-true what is false. Now one could analyze 'S knows that p' as follows:
a) S unconditionally accepts-as-true p
b) p is true
c) S is justified in accepting-as-true p.
This is modeled on, but diverges from, the standard justified-true-belief (JTB) analysis of 'know' the locus classicus of which is Plato's Theaetetus.
And one could perhaps analyze 'S believes that p' as follows:
a) S unconditionally accepts-as-true p
d) S does not know that p.
These analyses accommodate the fact that there is something common to believing and knowing, but without identifying this common factor as belief. The common factor is acceptance. A reason for not identifying the common element as belief is that, in ordinary language, knowledge excludes belief. Thus if I ask you whether you believe that p, you might respond, 'I don't believe it, I know it!' Do I believe the sun is shining? No, I know the sun is shining. Do I know that I will be alive tomorrow? No, but I believe it. That is, I give my firm intellectual assent to the proposition despite its not being evident to me. Roughly, belief is firm intellectual assent in the absence of compelling evidence.
Surely this is what we mean by belief in those cases that clearly count as belief. Lenny the liberal, for example, believes that anthropogenic global warming is taking place and is a dire environmental threat. Lenny doesn't know these two putative facts; he believes them: he unconditionally accepts, he firmly assents to, the two propositions in the absence of compelling evidence. And it seems clear that an element of will is involved in our boy's belief since the evidence does not compel his intellectual assent. He decides to believe what he believes. His believing is in the control of his will. This does not mean that he can believe anything he wants to believe. It means that a 'voluntative surplus' must be superadded to his evidence to bring about the formation of his belief. Without the voluntative superaddition, he would simply sit staring at his evidence, so to speak. There would be no belief and no impetus to action. Beliefs typically spill over into actions. But there would not be even a potential 'spill over' unless there were a decision on Lenny's part to go beyond his evidence by superadding to it his firm intellectual assent.
"But aren't you just using 'believes' in an idiosyncratic way?"
It is arguably the other way around. Someone who says he believes that the sun is shining when he sees that it is shining is using 'believes' in an idiosyncratic way. He is using 'believes' in a theory-laden way, the theory being the JTB analysis of 'knows.'
"But then isn't this just a terminological quibble? You want to substitute 'accepts' or 'accepts-as-true' for 'believes' in the standard JTB analysis of 'knows' and you want to reserve 'believes' for those cases in which there is unconditional acceptance but not knowledge."
The question is not merely terminological. There is an occurrent mental state in which one accepts unconditionally propositions that are not evident. It doesn't matter whether we call this 'belief' or something else. But calling it 'belief' comports well with ordinary language.
Let me now elaborate upon this account of belief, or, if you insist, of Aquinian-Pieperian belief.
1. Belief is a form of acceptance or intellectual assent. To believe that p is to accept *p*, and to disbelieve that p is to reject *p*. One may also do neither by abstaining from both acceptance and rejection. (Asterisks around a sentence make of the sentence a name of the Fregean proposition expressed by the sentence.)
2. If acceptance is the genus, then knowing, believing, and supposing are species thereof. In knowing and believing the acceptance is unconditional whereas in supposing it is conditional. It follows that believing is not common to believing and knowing as on the JTB analysis. To think otherwise is to confuse the genus (acceptance) with one of its species (belief).
[Species 1: Knowledge Species 2: Belief] [Species 3: Supposal]
Unconditional Acceptance Conditional Acceptance
3. What distinguishes believing and knowing is that the believer qua believer does not know, and the knower qua knower does not believe. Both, however, accept. What I just wrote appears objectionably circular. It may seem to boil down to this: what distinguishes believing and knowing is that they are distinct! We can lay the specter of the circle by specifying the specific difference.
If believing and knowing are species of the genus acceptance, what is the specific difference whereby the one is distinguished from the other? Believing that p and knowing that p are not distinguished by the common propositional content, p. Nor are they distinguished by their both being modes of unconditional acceptance. Can we say that they differ in that the evidence is compelling in the case of knowing but less than compelling in the case of believing? That is true, but then the difference would seem to be one of degree and not of kind. But if knowing and believing are two species of the same genus, then we have a difference in kind. Perhaps we can say that knowledge is evident acceptance while belief is non-evident acceptance. Or perhaps the difference is that belief is based on another's testimony whereas knowledge is not. Let's explore the latter suggestion.
4. It is essential to belief that it involve both a proposition (the content believed) and a person, the one whose testimony one trusts when one gains access to the truth via belief. To believe is to unconditionally accept a proposition on the basis of testimony. If so, then there are two reasons why it makes no sense to speak of perceptual beliefs. First, what I sense-perceive to be the case, I know to be the case, and therefore, by #3 above, I do not believe to be the case. Second, what I sense-perceive to be the case I know directly without need of testimony.
On this approach, the difference between believing and knowing is that believing is based on testimony whereas knowing is not. Suppose that p is true and that my access to *p*'s truth is via the testimony of a credible witness W. Then I have belief but not knowledge. W, we may assume, knows whereof he speaks. For example, he saw Jones stab Smith. W has knowledge but not belief.