“Now, what’s the difference between an invisible, incorporeal, floating dragon who spits heatless fire and no dragon at all? If there’s no way to disprove my contention, no conceivable experiment that would count against it, what does it mean to say that my dragon exists? Your inability to invalidate my hypothesis is not at all the same thing as proving it true. Claims that cannot be tested, assertions immune to disproof are veridically worthless, whatever value they may have in inspiring us or in exciting our sense of wonder.” (Carl Sagan, The Dragon In My Garage)
This is both a reasonable objection and an unreasonable one (ignoring the question of whether the ratio of ‘dragon’ prevents it from being incorporeal: it is reasonable because our natural mode of knowing is from sense to intellect. (Cf. Aristotle Physics I.1) Naturally speaking, the dictum “nihil in intellectus quod non quodammodo in sensu” is necessarily true; but it is unreasonable since (a) it is an utterly worthless argument against someone who proposes a supernatural mode of knowing since it begs the question by presuming that only natural modes of knowing are possible and (b) it makes the paradigmatically modern mistake of confusing intelligibility quoad nos with possibility and intelligibility in se (again, neglecting the fact that dragons are essentially corporeal).
Edit: Since I wrote this, I became aware of the following passage by Charles De Koninck, the erstwhile dean of the University of Laval’s School of Philosophy; since the inspiration for this post is this other post about an atheist’s objection to the doctrine of transubstantiation, the following passage is remarkably apropos to this topic:
The second part of his Enquiry (Section x) is directed against the Catholic faith. He attacks miracles as motives of credibility. This attack is, at ﬁrst glance, conducted most curiously. It opens with a disdainful charge against the
doctrine of the Real Presence: ‘‘a doctrine so little worthy of serious refutation.’’ Should this manner of procedure be attributed to stupidity or cunning? He cites the Eucharist as an example of the miracles to which the Apostles testiﬁed: “who were eye-witnesses to those miracles of our Savior”—and through which Christ proved his divine mission—“by which he proved his divine mission.” But, pursuing the point, he says that the doctrine of the real presence contradicts sense. ‘‘It contradicts sense, though both the scripture and tradition, on which it is supposed to be built, carry not such evidence with them as sense; when they are considered merely as external evidences, and are not brought home to every one’s breast, by the immediate operation of the Holy Spirit.’’
Manifestly, he here makes a twofold confusion. He supposes that we assimilate the certitude of the miracle as an extrinsic motive of credibility to the certitude of faith. But, more insidiously, he destroys the certitude of the extrinsic motive, he renders it even absurd, in citing, either through ignorance or intention, the miracle of transubstantiation as the exemplar of miracles through which the truth of the Christian religion is proved. He wishes to ignore the fact that transubstantiation is precisely an absolutely invisible miracle, that this miracle is in no way a sign of the truth of revelation and a motive of credibility. We adhere to it, in fact, by divine faith alone. This miracle is, in effect the one the Apostles neither saw, nor touched, nor tasted. They simply heard the words of Christ as we would have heard them. They reported them to us. And we believe in this miracle as did they—because Christ said it.
Notice the cunning—conscious or unconscious—of Hume’s method. Not only does he destroy the species of miracles which are extrinsic motives of credibility in citing the example of a miracle which does not belong to that species, but he destroys, at the same time, the sacrament which is the most hidden, the most profound, and the greatest in the whole of the Christian life. He attacks the faith under its purest form, that by which we adhere not only to that which is wholly invisible as is the most Holy Trinity, but also, and ﬁrmly, to that which contradicts the principle and origin of all our knowledge: the senses. He chooses the case where the divine truth is most manifestly beyond the intellectual knowledge which is based upon the senses. In the holy Eucharist, in effect, while the senses do not deceive themselves about their proper objects—they really are the accidents of bread and wine—it is nevertheless because of the senses that the intelligence, without faith, would fool itself as to the substance which is hidden under these accidents.
Visus, tactus, gustus in te fallitur,
Sed auditu solo tuto creditur.
Et si sensus deﬁcit,
Ad ﬁrmandum cor sincerum
Sola ﬁdes sufﬁcit.
Sight, Touch, Taste fail in you,
But hearing alone is wholly believed.
And, even if sense falls short,
For strengthening the sincere heart
Faith alone suffices.
It is in the faith in this sacrament that God demands of us the most complete abnegation of that which is the most profoundly human—I mean the loss of our proper judgment upon the substance of the object most proportioned to our intelligence.
But there is more. God chooses to hide the body and blood of the divine Savior, not under the appearance of a nutritive substance produced by the operations of nature alone: He chose the appearances of substances produced by the application of human art: bread and wine.
The perfect hiddeness of this sacrum secretum suits the perfection of the faith, says St.Thomas. Since God wishes us to participate in this divinity that no creature can know through its proper powers—no one has ever seen God—is it not beﬁtting that he demands of us a total faith in this Sacrament of the Way, the Truth, and the Life; a universal faith where reason removes itself from its dependance upon the senses, the source of its knowledge? (Charles De Koninck, “This is a Hard Saying”)