Most logical analysis seems to proceed from the assumption that ‘true’ and ‘false’ are the only meaningful categories of truth value. There are some good reasons for trying to reduce truth value to this binary contrast, but in practice, people actually employ a pretty broad range of options when assessing the truth value. Sometimes we just affirm a statement and sometimes we deny it, and there is good reason to aim for this goal whenever it can be achieved, but sometimes real people faced with real claims respond in other ways, at least some of which may be reasonable responses to questions of truth value. Sometimes we ‘problematize’ a statement (this was quite a fashionable word when I hit graduate school), which is to say we raise concerns about it without necessarily rejecting it altogether. Sometimes we give a statement a pass (i.e. we just don’t address it), and sometimes we find ourselves unable to decide whether it is true or false, even after making a serious effort to do so. In principle, we may think of truth values as binary, but in practice, we actually use a broader range of categories for assessing the truth value of statements.
Recognizing this variation in truth evaluation can help us to avoid bluffing or rushing to judgement, or for that matter fudging the issue in ways that simply don’t help. (I once had a logic class, for example, in which we were asked to assign truth values in terms of a percentage of truth.) My goal in opening up a broader range of possibilities than most seem to acknowledge is not to suggest abandoning the question to assign a definite value; it is to increase clarity about the instances in which that goal has, not been achieved.
What labels do we want to use? What follows is not an exact science. It is just a series of categories designed to reflect the different kinds of outlook we can take on a given statement, the different ways we can think about its truth or falsehood. This list reflects my own sense of the possible outcomes whenever I try to assess truth value in my own life. They are the responses, I actually see myself using. Anyway, I would suggest the following labels:
False: When you think a statements is false. This is the label you want to use for it.
Indeterminate: Sometimes you just can’t tell whether a statement is true or false. This may be because you don’t know enough about the subject matter to assess whether any claims made about it are right or wrong, and sometimes the issue in question is just so complicated that the more you know, the harder it is to say one way or the other. In such cases, we want to acknowledge that we cannot determine the truth value of the statement.
We can break the ‘indeterminate’ value down into a few different categories depending on the specific considerations that lead us to it.
Soft: Sometimes you just don’t know enough about a subject to say one way or another whether a claim made about it is true. It’s not that the answer is unknowable; it’s just that you don’t yourself know the answer, and you are not planning to do the research to find out. Fair enough! In such cases, you could say that truth value of the statement in question is ‘indeterminate (soft).’ Note: If you were actually debating someone and this was how you thought about a claim they made, it would probably be appropriate to give the claim a pass or treat it as true by default (see below). Unless you are prepared to argue the point, it would be rude and unhelpful to just withhold judgement and refuse to engage in any explicit discussion of the claim. Under normal circumstances, an ‘indeterminate (soft)’ value should result in giving the claim an effective pass. The only time I would consider using this would be if I knew the claim was critical to an argument despite my own personal inability to make a judgement about it. Even then, I would tend to grant the benefit of the doubt to the author of the argument.
On Hold: Sometimes, you don’t know enough to make a decision at the present time, but it’s worth doing some research on the subject. If you really are planning to take steps to help you understand the issues necessary to assess the truth of a statement, then you might say the value of the statement is (as far as you are concerned) ‘indeterminate (hold).’ If you were talking to someone about the subject when you came to this position, you might want to ask them to give you some time to think about it. Barring any specific time constraints, most reasonable people will grant this.
Hard: Sometimes, the truth of a given question is simply beyond our means to answer it, at least for the foreseeable future. This does not necessarily mean that the question is inherently unanswerable, just that you are unlikely to achieve a satisfactory answer given your present means of addressing the issue. Was Abraham Lincoln enjoying the show when he was shot at Ford’s theater, for example? We can ask the question, but it is unlikely (though not impossible) that we will find an answer for it. When this kind of problem arises, we want to provide some indication of it. In such cases, you might say that the statements has the value of ‘indeterminate (hard).’ We don’t know whether or not it is true, and we are unlikely to learn any time soon.
Variable: Sometimes critical thought about a given statement leaves us with the impression that a given statement may be true in one sense and false in others, or that some specific circumstances will radically change its truth value. In such cases we could say that the value of a statement is ‘indeterminant (variable).‘
Default (True or False): Sometimes we have to make choices in the absence of clear information about the truth of a given claim. In such cases, our judgement may be determined by a default value. In criminal courts within the United States, for example, defendants are considered innocent until proven guilty beyond reasonable doubt. In such cases, the default judgement for a claim that someone is guilty of an offense is to regard the accusation as false until given good reason to believe otherwise. There may be other contexts in which default judgements are critical to resolution of a problem, in which case, we could say that a given statement is considered ‘true by default’ or false by ‘default.’
It’s worth bearing in mind that default truth values may be more trouble than they are worth. Christian apologists and atheists, for example, will often spend an entire conversation debating the question of which party bears the responsibility to meet the burden of proof, which is essentially a question about default truth values. In such cases, the debate over burdens of proof will often be the only debate they ever actually end up having, this derailing the very discussion such questions are supposed to help frame in the first place. Some default truth values may not be this tricky, but do not be surprised if appeal to a default value draws an objection from others when you express your thinking in these terms.
Pass: When you skip evaluation of a statement, you are giving it a ‘pass.’
True: When you are relatively sure that a statement is just true, you would use this label for it.
True With Reservations (or Caveats): Sometimes a person is prepared to vouch for the truth of a claim, but with some reservations. They may be concerned about specific implications of the statement, or they may hold out for the possibility that some unknown fact could change their judgement on the issue. In principle, this is the roughly same as an ‘indeterminate’ value, except in that it begins with a positive affirmation. In such cases, we would say that we regard a statement as ‘true, but with reservations’ or ‘true with caveats’.