There is often some confusion surrounding the terms: belief, disbelief, agreement and disagreement when used in a philosophical context. We need to keep in mind that normal dictionary definitions are often not precise enough to be used in a philosophical context where precision and clarity are essential. (For analytic philosophy.) In this article I will explain the terms ‘belief’ and ‘disbelief’, and ‘agreement’ and ‘disagreement’. Then I will suggest a new way to define the terms in the name of clarity.
Belief and disbelief
I’m not going into some advanced theory of how humans believe things. I’m merely going to the contrast between believing something and disbelieving something. The confusion lies not with the word ‘belief’ but with the word ‘disbelief’. Some take ‘disbelief’ to be a mere lack of belief in something. Others take ‘disbelief’ to be a belief in the negation of something. It is this latter meaning that is usually meant in philosophical context. Going by the normal meaning of ‘belief’ and the second meaning of ‘disbelief’ we should then be able to see that this is a false dichotomy; One does not either believe something or disbelieve in something. There is a third option, that is, that one has no belief at all on the matter.1 Here’s a table that shows trichotomy along with a symbolic logic representation of the options:
| Options | Formalization |
| I believe something. | B(p) |
| I don’t have any opinion about something. | ¬B(p)∧¬B(¬p) |
| I disbelieve in something. | B(¬p) |
Note: Replace ‘something’ in the table with some particular proposition. Philosophers usually just write p which is what I have done in the formalization to the right.
The confusion is often between row number two and row number three. Especially when the ambiguous phrase “I don’t believe that something” is used. Taken literally this phrase means the first part of the second row2 but people usually mean the third row when they say it.
I suggest that, for the sake of clarity, that one ought to use “I believe something” to mean the first row, “I have no opinion about something” to mean the second row, and “I disbelieve in something” to mean the third row. To mean a lack of belief in something I suggest using the phrase “I have no belief that something”. Avoid using the phrase “I don’t believe that something” because it is ambiguous.
Agreement and disagreement
Having understood the above we can move on to the second part of this article. I suggest that we define agreement and disagreement in an analogous way to the above defined words. This means that to be in agreement about something with someone is to believe the something that the other person believes. To disagree with someone about something is to believe the negation of what the other person believes. Note that the common usage of ‘disagree’ is to merely not believe the something that the other person believes. I suggest that if one wants to say that one does not believe the something it is that the other person believes, then one ought to say “I don’t agree”. If one accepts this redefinition in the context of philosophy, then one should see that the dichotomy between agreeing and disagreeing is false. It is possible to not hold an opinion at all about something.
1I mean ‘the matter’ in a strict sense. Here’s an example. Suppose the matter is ‘one ought to vote for the republican party’. Then the matter is only that. Beliefs about whether one ought to vote or note, or to vote for the democratic party are not relevant.
2That one has no belief in something. [¬B(p)]