Logical consistency is sometimes treated as if it were something only a pedant would concern himself with. Consider Walt Whitman’s celebrated, but quite stupid, remark: “Do I contradict myself? Very well then, I contradict myself. I am large, I contain multitudes.” Similarly, Emerson asserted: “A foolish consistency is the hobgoblin of little minds, adored by little statesmen and philosophers and divines. With consistency a great soul has simply nothing to do.” The implication of such remarks is that there is something more, something deeper, in the thought of a self-contradictory person than in that of a consistent person. In fact, the opposite is the case. There is less in the thinking of a self-contradictory person, not more.
As Aquinas notes, a contradiction “implies being and non-being at the same time” (Summa Theologiae Hence it takes back with one hand what it seemed to be giving with the other. Consider, for instance, the notion of a round square. To posit a square is indeed to posit a kind of thing. But to posit that that thing is round is, as it were, precisely to take away the squareness (since the roundness is incompatible with the squareness), and thus to take away the thing itself. And the roundness goes with it too, since it now lacks anything in which it might inhere. Thus, the notion of a round square does not give you both roundness and squareness. (“Multitudes!”) Rather, it gives you neither roundness nor squareness. ).
The same is true of any system of ideas that incorporates a contradiction. It is self-annihilating, in just the same way that the notion of a round square is. Logic students are familiar with the dictum that anything follows from a contradiction. The Whitmans and Emersons of the world might think: “Anything? Great! Multitudes!” But once again they’d be wrong. What follows instead is that no proposition in a self-contradictory system can stand. The presence of the contradiction makes it possible to refute every one of them. It is not some tonic that makes the system more fruitful, but a cancer that eats its way through the whole. Hence, a self-contradictory system of ideas doesn’t give you everything you want. It gives you precisely nothing.
This brings us to Geach. Criticizing those who characterize inconsistency as merely a kind of relation holding between statements in a discourse, he points out that in fact it inevitably has bad practical consequences:
In fiction, indeed, inconsistency is a merely internal fault, and does not matter so long as it does not offend the reader. This holds precisely because the indicative sentences in a work of fiction do not latch onto reality: the author and the reader merely make believe that they do so. When discourse is meant to latch onto reality, then inconsistency matters: not because falling into inconsistency means perpetrating a specially bad sort of error, logical falsehood; but because inconsistent discourse inevitably has some non-logical fault. Like it or not, an inconsistent history will somewhere be factually false, an inconsistent set of orders or instructions cannot all be carried out, an inconsistent moral code will at some juncture be prescribing morally objectionable conduct, and so on. (p. 38)
Geach does not bring up nominalism in this connection, but he could have. The nominalist takes our concepts to be mere artifacts of language, free creations of the mind bearing no necessary connection to mind-independent reality. The realist, by contrast, takes concepts to reflect the natures of things themselves. Contradiction in a system of ideas is bound to seem less dire in its practical consequences on the former sort of view than on the latter. I’ll come back to this.
It is sometimes suggested that science might give us reason to revise logic by giving up consistency, but as Geach notes, this is simply muddleheaded. It has the same self-defeating character that any other inconsistent positon does. He writes:
As for proposals to bend logic, logic must remain rigid if it is to serve as a lever to overthrow unsatisfactory theories; otherwise refutation of a theory by contrary facts could always be staved off by enfeebling the logic that shows the contrariety.
Logic can never be constrained to withdraw a thesis by reason of a rival thesis established in some other discipline; for in a sense logic has no theses, being merely concerned with what follows from what. Logic is like a constitutional queen of the sciences: a queen who can never initiate legislation, but unlike the British monarch can put in a veto – on the score of inconsistency or fallacious reasoning. (p. 39)
The very practice of science presupposes consistency – most fundamentally, the consistency of theories with their evidential basis and with each other. Therefore, to give up consistency, even in the name of science, is to give up science. But neither can any claim of theology justify us in giving up consistency, as Geach rightly insists, despite his insistence having, he reports, “sometimes offended pious ears” (p. 41).
You might think those ears are always orthodox ones, but in recent years it is those who would revise traditional teaching who are most likely Typically they do so in the name of Christian mercy, but like those who would abandon consistency in the name of science, this is simply muddleheaded and self-defeating. Suppose you argue that mercy requires us to permit unrepentant adulterers to take Holy Communion, despite this being inconsistent with the Church’s perennial and infallible teaching. Strict consistency with traditional teaching is less important than showing mercy, or so you argue..
Yet what you are claiming is precisely that not permitting adulterers to take Holy Communion would be inconsistent with the mercy Christ commands us to show the sinner. (To be sure, this claim is false – there is no inconsistency at all, since Christ makes repentance a condition of forgiveness – but that is your claim.) So, you can hardly dismiss consistency when your critics point out that your view contradicts Church teaching, because your whole case itself rests on an appeal to consistency. By rejecting logic’s demand for consistency when defending your own position, you undermine that position itself.
We must, however, immediately note a distinction drawn by Geach. Inconsistency, he points out, is not the same thing as nonsense, though philosophers are not always careful to note the difference (pp. 41-42). When two statements are known to be inconsistent with one another, that presupposes that each has a clear meaning. By contrast, nonsensical assertions do not have a clear meaning. And precisely because they do not, they cannot clearly contradict one another. Logical methodology itself presupposes this distinction. Geach writes:
Reductio ad absurdum works by deriving a patent inconsistency from a set of premises, which shows that one or other of the set is false; this valuable method of proof would be a ridiculous procedure if patent inconsistency were not to be distinguished from unconstruable nonsense. (p. 42)
Now, the “saving grace” (if that is the right phrase for it) of Pope Francis’s own doctrinally problematic statements on matters concerning Holy Communion for adulterers, capital punishment, and the like, is precisely that they do not have a clear meaning, and that he refuses to clarify them. His statements thereby avoid actual inconsistency with past teaching, even as they seem to give wiggle room to those who would like to abandon it.
But they only seem to do so. For suppose a Catholic really does abandon past teaching. Then he either has to give up consistency itself, which entails a self-defeating position for the reasons I have been setting out in this post; or he can preserve consistency and reject just the past teaching, but in that case we will end up with a self-defeating position of another kind, the kind described in on Geach’s critique of modernism (since by holding that the Church erred in the past, he will have undermined any reason for believing what she teaches now). Hence there is no possible way to accept the pope’s problematic utterances except as imperfect formulations of claims that are consistent with past teaching. Any alternative way of construing them entails a self-defeating position.
One reason people don’t think clearly about these problems is that they don’t strictly think about them at all. Geach makes the important point that grasping the consistency or inconsistency between claims is an exercise of the intellect rather than of the imagination. He notes that “we can imagine things that on reflection are self-contradictory,” and gives the following example:
shows a stairway running round the four sides of a tower, on which by continual ascent one gets back to the starting point. (p. 43)
One might suppose that, because he can form a mental image like the one in Escher’s drawing, he has thereby grasped that the scenario it represents is really possible. But that is an illusion.
Similarly, those deluded into supposing that allowing unrepentant adulterers to Holy Communion can be made consistent with Christ’s teaching no doubt call to mind all kinds of happy mental images and feelings. For example, they might bring before their mind’s eye a picture of some man who has abandoned his first wife and formed a “new union” with another woman, happily leaving the communion line, being greeted with handshakes and good cheer after Mass, etc. And they might imagine also the unpleasant feelings of guilt this man might suffer if he were told that he is committing mortal sin by doing these things. This mélange of pictures and emotions triggers the word “mercy,” and they are thereby sold on the idea. (Of course, it helps if they do not call to their mind’s eye any images of the wife who was abandoned, what she and her children might be feeling, etc.)
Psychologically, this sort of process can be effective in winning over people of a certain mindset. But logically speaking, it is completely worthless, the sheerest sentimentality. It does exactly nothing to justify departure from the Church’s traditional teaching and practice.
Perhaps it is clear already what all of this has to do with questions about believing something on the basis of some authority. Geach argues that “it would wholly discredit revelation if it were supposed to proceed from a deity who may lie when he sees fit” (p. 58). To be sure, it doesn’t follow that God might not sometimes allow us to be misled, for as Geach also notes, misleading someone does not entail lying to him. (For example, if you leave the light on when you’re away, a burglar might judge that you’re home and therefore avoid your house. But though he’s been misled, he hasn’t been lied to.) But to posit outright lies in some purported divine revelation would be to undermine confidence in any of it. If what God purportedly has said in this one place is false, why suppose anything else he has said is true?
We saw Geach make a similar point when we recently considered A purported source of divine revelation is either reliable as a whole, or it is not reliable at all. To be sure, and as Geach acknowledges, we do sometimes trust human beings even when we know they have lied. But the case of a purported divine revelation is different, for (unlike the case of human testimony) we have no independent means of verifying doctrines that are supposed to be knowable only via such revelation. , and it is related to .
It is crucial, then, that a purported source of revealed doctrine be consistent. If there is any inconsistency in it, then the inconsistent statements it contains cannot all be true. If they are not all true, then some of what it teaches is false, which (again) undermines the credibility of the whole. This is the case not only with scripture, but also with all statements claimed to have been taught by the Church in a definitive way, such as decrees of ecclesiastical councils, infallible papal pronouncements, and . To allow that there is error in any of this would undermine the credibility of all of it. In response to the suggestion that ecclesial authority may, by fiat, put forward some new teaching that contradicts the old, Geach says:
Bishops come and bishops go; and one Pope passeth, another cometh; ay, Heaven and Earth shall pass; but from the Law of Contradiction not one tittle shall ever pass; for it is the eternal Law of God. (p. 69)
Amen! And before you accuse Geach of subordinating theology to philosophy, note well that he is in fact simply affirming Catholic teaching. For example, in that grand encyclical , Pope St. Pius X condemned the modernist thesis that theology can contain contradictions. (As the pope wrote: “But when they justify even contradiction, what is it that they will refuse to justify?”)
But there still might seem to be a flavor of paradox here. I may decide to reject some purported source of authoritative revelation, on the grounds that it contradicts itself; or I may judge that it does not contradict itself, and (if I also have some positive reason to think it really did come from God) accept it. But either way, am not I the one making the call? And in that case, do I not make myself the ultimate authority? Geach’s response begins as follows:
The question which authority to trust is difficult and inescapable. But we must steeply, most steeply, rebut the sophists who would argue ‘In accepting an authority you are relying on your Private Judgment that the authority is reliable: so Private Judgment trumps authority.’ Inevitably my judgment is my judgment, my very own judgment, thus my Private Judgment; but this is a mere tautology, from which nothing interesting can follow. (pp. 50-51)
What Geach refers to here is, of course, a standard Protestant objection to Catholicism. The nature of the fallacy identified by Geach might be clearer when we consider that a parallel accusation could be flung back at the Protestant, who claims to follow only scripture: “In accepting scripture you are relying on your Private Judgment that scripture is reliable: so your Private Judgment trumps scripture.” The Protestant might respond, quite correctly, that the fact that he has judged scripture to be authoritative simply doesn’t entail that he puts his own authority above that of scripture. For in justifying this judgement, he is not appealing to any purported authority of his own in the first place. But exactly the same response is open to the Catholic. The fact that he has judged the Church to be authoritative simply doesn’t entail that he puts his own authority above that of the Church. For in justifying this judgement, he too is not appealing to any purported authority of his own in the first place. Geach expands on the point as follows:
[W]hen I decide to follow one authority rather than another, I am not in effect setting up myself up as a superior authority. It would be quite difficult for me to give good reasons for trusting one lawyer or doctor rather than another; but such trust on my part need not be merely blind, nor on the other hand am I claiming to know more law than my lawyer and more medicine than my doctor. (p. 51)
I may judge one doctor to be trustworthy and another to be a quack. But it doesn’t follow that I claim to have greater medical expertise than the former. By the same token, when I judge one purported source of divine revelation (a book, a prophet, a Church, or whatever) to be genuine, and another to be bogus, it doesn’t follow that I claim greater expertise about divine revelation than the former.
As noted already, Geach acknowledges that in the case of fallible human beings, we do sometimes trust them even though we know them to have lied. Similarly, we do not always reject the authority of an expert simply because he has been inconsistent on this or that occasion. But there are limits. It cannot fail to undermine public trust when government officials, media sources, etc. repeatedly and shamelessly say inconsistent things. (Some recent examples: Right-wing mass demonstrations during the Covid-19 pandemic were dangerous super-spreader events, but left-wing mass demonstrations were not. Questioning the integrity of the 2016 election upholds democracy, but questioning the integrity of the 2020 election undermines democracy. The left-wing riots that occurred throughout the summer of 2020 were “mostly peaceful protests,” but the right-wing riot that occurred on January 6 of 2021 was an “insurrection” and “worse than 9/11.” Skepticism about Covid-19 vaccines is reasonable when Trump is president, but irrational when Biden is president. To fail to wear a mask in public is to put grandma’s life at risk, except when Democratic politicians or journalists fail to do so. Preventing a woman from killing her unborn child violates her right over her own body, but forcing her to take a vaccine injection does not violate her right over her own body. Etc.)
Churchmen too, when they exercise their fallible governing authority (as opposed to infallible ex cathedra papal definitions), risk losing the trust of the faithful if that exercise shows inconsistency. In my essay I discussed the double standard the pope has shown toward progressives and traditionalists – bending over backwards to accommodate the former even though they widely dissent from the infallible teaching of millennia, while harshly punishing the latter because some among them question more recent and fallible teaching. (That essay was recently reprinted in Peter Kwasniewski’s excellent anthology .) The Vatican on this harshness in a Responsa ad dubia prompted by Traditionis Custodes. Into the bargain, this response has added to the double standard evident in Traditionis directives that are .
notes how, if the principles of Amoris Laetitia and some other earlier pronouncements of Pope Francis were applied to the interpretation of Traditionis Custodes and the Responsa ad dubia, they would essentially gut the latter documents of any binding force. This is exactly what we should expect, given the points made above when discussing Geach. Since anything follows from a contradiction, an internally inconsistent set of principles inevitably subverts itself.
Earlier I mentioned nominalism, and historically (for example, Voluntarism holds that the will is prior to the intellect, in contrast to the “intellectualist” position defended by Aquinas, which holds that the intellect is prior to the will. For the intellectualist, the will is and ought to be the servant of the intellect. Hence the will cannot be rightly ordered if the intellect is not. And legislation, which reflects the will of the legislator, cannot be good if it does not conform to reason. For the thoroughgoing voluntarist, by contrast, the will is the intellect’s master rather than its servant, and it does not answer to the intellect’s rational scruples. (It is because metaphysical realism would put strict rational constraints on what we might intelligibly be said to will that nominalism is attractive to the voluntarist.)), nominalism has had a close connection with voluntarism.
Now, But the ecclesial and the political orders seem today to be dominated by what, in that same post, I labeled “the voluntarist personality” – a personality type which approximates what human beings would be like if voluntarism were true. The voluntarist personality type tends to be stubbornly willful and excessively emotional, but to have a relatively weak or poorly developed intellect. Hence it is highly impatient with calm deliberation, clear and explicit lines of reasoning, carefully drawn distinctions, and so on. It tends to evaluate ideas and policies, not in terms of the arguments or evidence that might be adduced for or against them, but rather in terms of the motives that it sees, or thinks it sees, in those who advocate them and those who oppose them. It thus tends toward self-righteous moralizing in defense of its favored positions, and toward ad hominem attacks against those who disagree. Naturally, it is not inclined to try rationally to persuade dissenters, but prefers instead to get its way by dictatorial command where it can, and by rhetorical manipulation, threats, and intimidation where it cannot., and as I noted in , traditional Catholic teaching clearly affirms it.
The voluntarist personality tends to conflate authority with raw power, and thus inconsistency in its demands does not bother it. “I’m in charge, and this is my will. Just do it, and don’t bother me with quibbles about logic and evidence!” The trouble is that voluntarism is false, and human beings are rational animals. Thus, in the long run, when those who govern them do so in an arbitrary and inconsistent manner, they will rightly see in this not the proper exercise of authority, but rather the abuse of authority. They will be tempted to schism and rebellion – which the ruler with a voluntarist personality will rightly decry, while being utterly oblivious to the fact that he is the one provoking it. The voluntarist personality tends to see in dictatorial fiat the apotheosis of authority, when in fact it is the corruption of authority, and threatens its dissolution. But here, I should note, I go beyond anything discussed by Geach.