There's Certainty and there's (Gangadeanian) Certainty.

The Gangadeanians assume (without argument) that knowledge (or knowing) requires certainty. In their minds, it would seem that they have a monopoly on concepts or the meanings of the correlate terms. But this is a mistake. Epistemologists for millennia have grappled with just what it means to know something. This is why I have labeled the Gangadeanians as semantic or conceptual chauvinists. To borrow from their language, they have a number of uncritically held assumptions, among them that they've got it right (and the rest of us wrong) as it concerns the nature of knowledge.

We (most contemporary epistemologists) reckon that knowledge is something more than a mere true belief and post-Gettier, we think knowledge is more than justified true belief (also see Bertrand Russell and Dharomottara for earlier cases). On the other hand, if you're a Gangadeanian, then knowledge is simply justified true belief. However, justification is really hard to come by because it requires certainty (it's impossible for you to be wrong about it) and that at least in some cases (when not self-evident), you are able to show or demonstrate that this is so with respect to the thing believed. In other words, for the Gangadeanian you only know that you have a body if the following are met:

(1) it's impossible for you not to have a body (so every skeptical scenario--in the words of David Lewis--"let your fantasies rip"-- is necessarily false) and

(2) you are able to demonstrate that this is so by way of deductive argument (inductive arguments or arguments that are meant to show that we have good reason to doubt we are merely brains in vats are not enough for knowing that you have a real body).

(1) and (2) are merely necessary conditions for knowing (or necessary conditions of an analysis of 'S knows that P'). There's also the truth condition (which may be entailed by (1) and (2)) as well as the belief condition--i.e., you can't know what is false, and you can't know what you don't believe. These additional conditions are common ground between me and the Gangadeanians. There's an issue about how the Gangadeanians, while staying true to their own system of proof, can grant these conditions as well, (can they prove that knowledge is only of that which is true and you can only know what you believe?) but I won't press that, here. What I will say in passing is that if you encounter someone who doesn't agree with you that knowledge is always of something that is true (i.e., you can't know something that is false), you can't prove them wrong (at least not in the Gangadeanian sense of proof). You just appeal to thought experiments (just like Gettier did!) so as to appeal to their intuitions. I've had more than one student over the years challenge me on the truth condition of the standard picture of knowledge and there is nothing like a sure-fire proof to get them to "come around."

This brings us to the point at hand. In a recent tweet, Kelly Fitzsimmons Burton included an excerpt from Strong's Concordance (a lexicon of Hebrew and Greek terms) which suggests that the verb to 'know' in the Hebrew is connected to certainty.

Burton isn't clear about precisely what this is intended to show. But it's likely that Burton thinks this is at least evidence that, as it concerns the Bible, (at least the portions that were originally written in Aramaic) knowing something requires being certain of it or being sure of it.

Two things to note. First, this isn't proof in the Gangadeanians sense of anything at all. More to the point: the fact that a particular dictionary says that P, doesn't show that ~P is impossible (remember condition (1) above). It takes little imagination to come up with a dozen or so skeptical scenarios in which the dictionary has got it wrong about the meaning of this particular word. Dictionaries are compiled by people who make mistakes--even semantic ones! So even if Strong's says this is the definition, according to Burton's own standards of knowledge, she won't count as knowing what the dictionary reports, unless she can prove that the opposite couldn't possibly be the case. What would it take to prove that the dictionary has got it right about the meaning of a word in a given language? As I've noted in the past, I don't think such proof is possible when you're dealing with the meanings of words or expressions in a given language--we have at best, empirical methods which are fallible (e.g., polling people to see how they actually use the word in that language). Now if you're thinking that I'm asking too much of Burton here, then you need to remember that I'm just holding her to her own standards! It doesn't matter that I don't personally endorse such standards of proof since I'm looking to point out that the Gangadeanian system is internally inconsistent.

But there's a bigger worry, here. Even if we grant Burton the assumption that the dictionary has got it right, we are left with asking what the authors of Strong's mean by 'certainty' and it's cognates. We need to know whether 'certainty' as featured in the excerpt means exactly the same thing as 'certainty' as it is being used by the Gangadeanians in their search for that which is "clear to reason." My worry has long been that the Gangadeanians are in the practice of making things come out true by re-definition. They use an ordinary term which their audience might be familiar with (terms like 'eternal,' 'God,' 'reason,' 'knowledge,' 'clear' and the like) and then at some point assert a rather self-serving definitions in hopes that their audience will not catch the fact that such definitions are philosophically loaded (and things to be argued for rather than merely assumed). Remember, whether one conclusion follows from another (i.e., whether an inference is a good one) depends in part on the very meaning of the words we assign to the sentences in question! So, the Gangadeanians are in the practice of offering conceptual/semantic Trojan horses.

Ask yourself now, what things do you take yourself to be certain of or sure of? My guess is that most people (including most philosophers) will cite various beliefs which are derived from their perceptual faculties. I am certain or sure that I am in front of a computer right now. I am sure or certain that I have a body, that it is sunny where I am located, that today's date is August 12th 2019, and that I am surrounded by colleagues who have minds. I am certain that the world wasn't created 15 minutes ago to look like it's been around much longer, and I'm sure that of the identity of my birth parents, my place of birth, and my date of birth, and a host of other very commonly assumed propositions. That's how I understand the ordinary concept or term 'certain' and its cognates. (Think about the humorous situation in which someone says, "so you're saying there's a chance..." attempting to exploit a remote or distant possibility to their advantage.  The reason such a line uttered in this sort of circumstance is funny is because the person making such a statement is pointing to a counterpossibility that is so remote or distant that it's effectively not worthy taking seriously and yet hoping to bank on it to argue a point.) However, importantly, this isn't how the Gangadeanians understand the notion/term.

According to their lexicon, I wouldn't count as being certain of any of the things I just noted, because I'm not in a position to prove that I couldn't possibly be wrong about them. I can't prove that I am not merely a mind that is part of a computer simulation, or the subject of a government conspiracy to lie about today's date (or my date/place of birth, or the identity of my birth parents), or to prove that my colleagues are not machines that merely look and act as if they are minded beings. Since I can't deductively prove these counterpossibilities to be false, on the Gangadeanian account of certainty, I don't count as being certain of any of those things enumerated above--and so I don't count as knowing any of them.

So there's certainty and there's (Gangadeanian) certainty. Gangadeanian certainty of any proposition requires being able to prove that the opposite is not logically possible. Even the tiniest chance that you could be wrong, no matter how wild the scenario, is enough to rob you of Gangadeanian certainty. The question then is whether the Gangadeanians have offered us any reason to believe that their notion of certainty is the "correct" one (or that we should care about it or accept it). They could do this by one of two ways. First, they might recognize that their concept of certainty diverges with that which is common in ordinary discourse and life, but somehow give an argument for why we should follow them and leave our ordinary notion behind. Alternatively, they can disagree with my observations here, and prove to us that there really is only one idea or concept of certainty--the Gangadeanian, one. In either case we need an actual argument(s) or better yet, proof(s). Of course, they might at this point play the "self-evident" card again and claim that denying that certainty is what they say it is is somehow self-refuting and likewise for their theory of knowledge, but that's not going to work. Merely taking these crucial assumptions for granted should not be acceptable practice for those seeking "clarity at the most basic level." So much for the extremely limited payoff of Burton's latest tweet. Even if Strong's suggests that the Aramaic correlate of 'knows' as featured in the Bible entails 'certainty,' that is short of showing that 'certainty' is what the Gangadeanians say it is.

p.s. There is a further ambiguity with 'certain' (and cognates) that is relevant--often, the word in our language seems to refer to something like a feeling or state of psychological confidence. That adds an additional wrinkle in Burton's attempt to use Strong's as a kind of proof text for her philosophical point. That's because the Gangadeanians think that knowledge requires epistemic certainty, not merely psychological certainty. Many epistemologists think that psychological certainty/confidence is a sort of necessary condition for (outright) belief--so on a standard picture of knowledge as requiring belief, the relevance of psychological certainty shouldn't be hard to see. But to insist further on epistemic certainty is the controversial bit. My claim is that the Gangadeanians haven't shown us that knowledge requires epistemic certainty.