Philosophers who do epistemology have traditionally defined knowledge as a justified true belief. Their definition raises an important question, namely, what is the nature of belief?What does it mean to believe anything at all?  This blog post will explore three standard perspectives on what beliefs are, and outline some implications of the view that I prefer.
1. The Humean View
While classical Greek philosophers tended to view belief as inferior to knowledge (it’s a matter of “mere opinion”) thinkers like David Hume brought belief into the foreground of discussions about knowledge. He thought that beliefs were feelings attached to ideas. An idea that I believe is different from one I don’t believe because of the vivacity or force of feeling that goes along with it.
Unfortunately, Hume’s reduction of beliefs to ideas with feelings had two main problems: first, sometimes our beliefs about mundane, trivial things are not attended by feelings at all, and second, vivid feelings may accompany an idea without my believing it to be true. So feelings are neither necessary nor sufficient for belief. But perhaps some feeling is essential to the nature of belief, if only the feeling of surprise or shock experienced when we find out that a belief if false.
2. The Behaviourist View
In response to Hume, other philosophers reduced belief to behaviour. This meant that belief was a matter of acting as if a proposition were true and had nothing to do with feelings or with concepts in the mind. But this behaviouristic view also had its problems. It had difficulty explaining why some people could “fake” their beliefs by behaving in all the appropriate ways and it couldn’t explain the fact that people often have contradictory beliefs. If belief is merely an action (or a disposition to act), then it is impossible for me to perform and not perform that action at the same time. Nor is knowing what I believe simply a matter of drawing conclusions from how I behave. There seems to be an intellectual or cognitive component to belief whereby I assent to the truth of a proposition, not merely behave as if it were true.
3. The Dispositional View
Many philosophers today (myself included) reject the Humean and Behaviourist views in favour of a multifaceted approach that connects beliefs to thoughts, feelings, and actions. My own preference is to define a belief as a disposition to think, feel, and act as if a proposition is true. Allow me to unpack that definition a bit.
By “disposition” I mean the property of being inclined (or likely) to exercise particular powers under certain conditions. As a person, I have the power to think, feel, and act – and if I am likely to use those powers in certain circumstances, then I have “disposition” to exercise them. Beliefs, then, are dispositions to exercise those powers in a certain way, as if a proposition is true. Note: in calling beliefs “dispositions”, I’m not claiming that all dispositions are innate. Some might be innate (e.g. a “hard wired” belief that the external world exists), others will be acquired very early in life apart from our control (e.g. under the influence of parents), while others will be more or less up to us.
The first implication of the dispositional perspective is that I can have beliefs I am not aware of. Dispositions often take the form of habits and practices which run deep in the human psyche and elude my attempts at introspection. Consequently, there will be times when I am surprised, even embarrassed, by the beliefs I actually hold.
A second implication is that the “feeling” component of belief is still rather ambiguous. Why? Because there are many beliefs which I have no feelings about at this present moment (e.g. that there is a paper clip in my drawer). To accommodate this worry, my view requires that feelings be involved in specific circumstances of belief change. For example, it would be a minimal requirement of the dispositional view that that I feel somewhat surprised when I discover that one of my beliefs is false or somewhat confident when I see the evidence supporting my belief.
So that’s my view. But I’m curious, what do you think a belief is?
 I am indebted to Louis P. Pojman’s for some preliminary insights to do with the nature of belief. See he helpful book What Can We Know? An introduction to the Theory of Knowledge (1995), pp.246-61
 One might add to this definition by saying that the dispositions must result from the intentions of the believing agent, but I take this requirement to be too strict. Some beliefs are not acquired or maintained through any intentional contribution on the agent’s part, and so the agent is not responsible for having the belief she has. Moreover, one might object to my definition of belief on the grounds that it is too behaviorist, i.e. if I act as if I believe something, then I believe it. But I doubt this objection has any real force. It is one thing to be able to deceive people about your beliefs by modifying your behavior. But it is rather odd to suggest that I have a disposition to think, feel, and act as if something is true yet not really believe it.
 Now, there are unique circumstances in which my powers are suspended (say if I am temporarily unconscious) but my disposition to exercise them still remains whether I am asleep or awake. I don’t lose my beliefs whenever my powers of thought, feeling, and action lay dormant.