Epistemic Necessity and the Good
The connection between metaphysical necessity and the Good is speculative and questionable, though there are signs of affinity.[1] But the connection between epistemic necessity and the Good is immediate and easy to discern: it goes via certainty. If a given proposition is epistemically necessary, it is certain: I am certain that I exist and that I think. To be epistemically necessary is to be certain. By contrast, epistemic contingency is the same as doubtfulness: you might turn out to be wrong. It is the difference between confidence and diffidence, being sure and being unsure. Certainty is good and uncertainty is not so good (sometimes quite bad). We would all like to be (justifiably) certain of everything, if only we could; but we live with uncertainty, however uncomfortably, there being no alternative. Uncertainty is a necessary evil. We therefore seek certainty and try to avoid uncertainty: we prize epistemic necessity. We like the idea that we can’t be wrong—that our reasons necessitate our conclusions. We value the necessity of logical entailment. This is what gives rise to epistemic necessity. If nothing ever entailed anything, there would be no such thing as certainty. Logic is a good thing.
But why is certainty good? Two ideas come to mind: certainty is instrumentally good in relation to desire; and certainty feels good in itself. If we can’t be wrong, we can’t be wrong about what will satisfy our desires; in the ordinary sense, I am certain the supermarket is open on a Sunday, so I go there to pick up food—and I am never disappointed. But if I am rationally doubtful, I might end up hungry. This is the basis of epistemological pragmatism—pragmatism about the value of certainty. Alternatively, it might be maintained that it feels good to be certain and not good to be uncertain—the former is more pleasurable. I think this is true and not a negligible point, but I don’t think it is the end of the story. It isn’t simply a matter of hedonism—the higher pleasures and all that. Something more interesting is going on, which gets to the heart of epistemology. We value certainty because we value knowledge, and knowledge requires certainty. What kind of certainty is a debatable point—philosophical certainty or commonsense certainty. In the ordinary sense, we have a good deal of certainty, as in the supermarket example, so we have a good deal of knowledge. That’s good, because knowledge is good. Epistemic necessity gives us knowledge, and we happily accept the gift. Doubt undermines knowledge, and the more doubtful the more the undermining. But why is knowledge good? That is a very good question. Is knowledge to be defined as something like true justified belief or is it more like direct perception of a fact? The former leads naturally to a pragmatic conception of the value of knowledge—knowledge is what gets you fed (so banal, so boring!). The latter opens up a more interesting proposal: knowledge is good because it connects the self to the world. We value knowledge because it is direct apprehension of reality—and we value this in its own right not because of pragmatic consequences. We value knowledge for the same kind of reason we value friendship or romantic love—because it relieves existential isolation. So, we value epistemic necessity because we value certainty, and we value certainty because we value knowledge, and we value knowledge because we value connection. We like to merge (“Only connect!”). And we do merge: perceptual consciousness presents the objective world to us as separate but also possessed. According to the Cogito, I am connected in this way to myself—not remotely but immediately. It would be terrible to be disconnected from myself, as if I were a mere hypothesis (like black holes or dark matter or fairies). It would also be good to be at one with my environment—and I am by virtue of seeing it and touching it. I am not cut off from it, blind to it, ignorant of it: I know it, as I know myself. That is, I enjoy acquaintance with my environment, as I enjoy acquaintance with other people and animals. I am not stuck inside my own inner world, just a passing show of inchoate sensation—that would be a kind of hell. This kind of perceptual acquaintance is part of what makes life valuable, worth living. Luckily, we have quite a bit of it (pace the philosophical skeptic). We are not blindly guessing from a distance, hoping against hope that there is something out there. It’s good to be in the know, well acquainted, in with the in crowd, part of life’s rich pageant—not a stay-at-home, a shut-in, a reluctant lonesome cowboy. Knowing is part of human existence, perhaps the main part. But not that etiolated sort of knowing beloved of the analytical philosopher (true-justified-belief knowing) but embodied-direct-perception-of-actual-concrete-facts knowing, as in seeing the sun rise in the morning.[2] We have epistemic connection to thank for that. It is something quite profoundly meaningful. I am at one with the world not a self-enclosed particle. Perceptual knowledge has human value.
Does all this have any bearing on metaphysical necessity? None at all, you might reply, these being quite different concepts. You are not wrong there, to be sure, but is there no connection at all between the two concepts? After all, the word “necessary” is used for both (which has caused a lot of confusion about the distinction); and the epistemic use might spill over into the metaphysical use by association. But more forcefully, epistemic necessity is defined by metaphysical necessity (but not vice versa): for it involves the idea of a set of reasons entailing a conclusion, and entailment is a metaphysically modal notion, i.e., the reasons necessitate the conclusion. In all possible worlds in which the reasons obtain the conclusion obtains.[3] There is such a thing as epistemic necessity only because there is such a thing as metaphysical necessity. We therefore can’t value the former without valuing the latter. There is only knowledge because metaphysical necessity exists, i.e., premises entail conclusions. Certainty requires that the grounds necessitate the inference, as in the Cogito. To put it differently, there has to be a type of non-epistemic necessity for there to be epistemic necessity (even if it doesn’t add up to what the logicians regard as necessity). You therefore can’t value the one without valuing the other. The case is similar to nomological necessity: there can’t be epistemic necessity (certainty) without nomological necessity, since we rely on laws of nature in all our reasonings, so we can’t value epistemic necessity without valuing nomological necessity. It’s good to be certain that the supermarket is open on Sunday, but this requires that there are laws of nature concerning shop openings, worker availability, motion, etc. Nomological necessity is good because it enables epistemic necessity (inter alia), which is itself good. We are glad there are laws of nature otherwise we couldn’t be sure of anything, and we like to be sure. We like to be sure because we like to know. And we like to know because otherwise it would be a pretty dismal isolated existence. Plus, it feels nice to know things and it gets you fed. There are reasons why necessity is regarded as good.[4]
[1] See my papers “Is Necessity Good?” and “Necessity and Change”.
[2] See my “Perceptual Knowledge” and “Non-Perceptual Knowledge”.
[3] See Kripke’s discussion of epistemic necessity in Naming and Necessity.
[4] It is also true that I know what I know necessarily in central cases. For example, if I am seeing a certain color and I know that color “by acquaintance”, I necessarily know it—I can’t help knowing it (compare pain). Necessarily, if I am acquainted with X, I know X. Likewise, I necessarily know that I exist, by the Cogito: I can’t not know it. This is another way in which metaphysical necessity is connected to epistemic necessity. In general, if I am certain that p, I must know that p. If I’m certain that I’m thinking, I can’t not know that I’m thinking—the knowledge is forced on me. There are many metaphysical necessities of epistemic truths, i.e., things I can’t help knowing.
