There are various more or less familiar acts by which to communicate something with the reasonable expectation of being believed. We can do so by stating, reporting, contending, or claiming that such-and-such is the case; by telling others things, informing an audience of this-or-that, or vouching for something; by affirming or attesting to something’s being the case, or avowing that this-or-that is true.
What do these acts have in common? Each is an instance of the kind of speech act known as an assertion.
Acts of assertion are of great philosophical significance.
For one thing, assertions are apt for transmitting knowledge, and so they are of interest to the theory of knowledge. (What is knowledge, such that it can be transmitted through speech in this way?) For another, it is by asserting things that speakers typically express their beliefs. As a result, acts of this type can shed light on the relation between mind and language, thought and speech.
Third, assertions appear to be part of a very complicated social practice, one in which speakers and hearers expect things of one another, and hold one another responsible in various sorts of ways. For this reason, assertions should be of interest to social philosophy and ethics. (How does it come to pass that speakers and hearers have these expectations of one another, and what entitles us to hold each other responsible in these ways?)
The systematic study of assertion, then, would appear to require a mixture of philosophy of language, philosophy of mind, epistemology (theory of knowledge), ethics, and social philosophy. Is there any way to discern order in this chaos?
Recently, a number of philosophers have proposed that we think of assertion as a particular type of move in a “language game.” On the most basic versions of this proposal, the rule for making the move of assertion is simple: one must do so, only when one is relevantly authoritative on the matter at hand; that is, only when one has the relevant evidence or knowledge. For example, a speaker who asserts that it is sunny, but who fails to have evidence (let alone the knowledge) that it is sunny, has violated the assertion rule.
According to such a proposal, the assertion rule characterizes the nature of assertion, and distinguishes it from other kinds of speech act (requests, commands, speculations, promises, offering congratulations, and so forth). In effect, the assertion rule suggests that “assertions are the only speech act backed by the promise of the speaker’s authoritativeness”. If we assume that this rule is common knowledge to all members of the language community, then the rule of assertion would appear well-positioned to account for assertion’s philosophical significance.
To see this, suppose Sally makes an assertion that it is sunny today, and that Nancy observes and recognizes the assertion that is being made. Then (given that the assertion rule is common knowledge) it is common knowledge that Sally’s act is proper only if she has the relevant evidence or knowledge: this is something that both Nancy and Sally know, and that each knows that the other knows. But then Nancy would hold Sally responsible for having the relevant evidence or knowledge, and Sally would expect as much.
On this account, the rationality of Sally’s hope of being believed lies in this: she can anticipate that Nancy appreciates the promise of relevant authoritativeness in her assertion. Insofar, as Nancy is entitled to think that this promise was kept, Nancy is entitled to think that Sally has the relevant evidence or knowledge, in which case it would be reasonable for Nancy to believe her.
Something along these lines would also appear to explain the role assertion plays in the spread of knowledge.
In a similar way, we might think to develop an account of the ethics of communication by using the assertion rule. On such a view, what we are entitled to expect of one another in our information-exchanging practices is governed (at least in part) by that rule. The rule itself entitles hearers and speakers to expect things of one another, and the failure to satisfy those mutual expectations generates the possibility of moral censure.
The assertion rule also holds out the prospect of shedding light on other features of our linguistic practices. For example, we might hope to be able:
- to explain why conditions of anonymity have characteristic effects on the quality of assertions made under such conditions.
- to understand when it is proper to retract an assertion under conditions of disagreement.
- to model the way in which members of various groups “calibrate” their expectations of one another in contexts of information exchange.
- to highlight the nature of what Miranda Fricker calls the “epistemic injustice”, perpetrated when a hearer dismisses another’s assertion out of prejudice.
- to think about the reformation of our practices of assertion, so as to ensure fair treatment to all in our knowledge communities.
In sum, assertion is a topic that will repay sustained philosophical reflection, and the rule of assertion appears to unify what otherwise might seem to be a host of unrelated facts about our linguistic practices.