Reading Dark Night of the Soul one encounters a passage in which St. John of the Cross gives the fairly traditional view of St. Paul's "thorn in the flesh." During a recent community meeting, one of the community members asked me, "How did he (St. John of the Cross) know that St. Paul's thorn in the flesh was lust? I'd never heard that before."
I responded, perhaps vaguely, but appropriately, "Because he was male." The ambiguity here is which he I was referring to, but it works for both. St. John of the Cross understood because he was male, and the thorn in St. Paul's flesh being lust was perfectly understandable to any other male.
The human male is a very, very simple animal. If two simple needs/desires are satisfied (one of them is food), we tend to be a pretty contented lot. Upset the schedule of one or the other, we tend to get out of sorts.
Yes, it's a vast simplification, but when I think of the capital vices/capital sins and I look at much of human history and human legend, one crops up more often than any other, and it isn't pride. In fact, if one considers the idiotic things done in the name of "love," one can readily conclude that for most men pride takes a far distant second place to lust as the most common besetting sins. For example, Helen of Troy (admittedly legend), the rape of the Sabine women, the reign of Henry VIII, the reign of W J Clinton and role model JFK--the roll call goes on and on.
Judging by the state of society today, it is fairly evident that everything is set to keep that particular vice at a fever pitch. Now, this is not to say that the impulses in this direction cannot be subdued or with the aid of grace resisted. But one glance at the present state of society which, whether feminists like it or not, is a male-construct to which "liberated women" have foolishly consented in their desire to become more and more like men, shows the basis on which almost everything is done, sold, or considered. Again, I'll grant that it is a simplification, but there is an element of truth to it. That element is sometimes expressed in the outrage against celibacy and its native chastity. Some are outraged over the celibacy requirement, calling it unnatural, unrealistic, and gravely disordered. When I look at the same state, I do see something that is not natural--rather it is supernatural--a state exalted above that of most of us and preserved purely by grace. When a priest from time to time fails at maintaining this state of life, that too is likely in God's grace--a lesson in humility, because his fall is a matter of public notice. He cannot do what many in society do casually without causing scandal. But society at large is threatened by it because it is a sign that the thorn in the flesh can be removed or at least made subservient to the person who experiences it. Presently, one would think that the thorn was, in fact, the entire flesh and that such was a normative existence.
St.Anthony of the Desert heroically fought off the demons of lust throughout his time in the desert. St. Augustine, Blessed (?) Charles Foucault, and a great many others, perhaps many we do not know, spent a great deal of energy fighting those impulses that comprised for them "the thorn in the flesh."
In our conversation, I did go on to confide that I honestly didn't know what might form the most common or besetting sin among female kind. (Some women, exhibiting the need and desire to be more like men, have foolishly accepted the male vision of the world and see promiscuous and untethered sexual conduct as normative, rather than as the degrading objectification of persons that it actually is. Sexual congress outside of the sacrament of matrimony is sinful precisely because of its tendency to turn an person into a object. And, in fact, this can be a problem even within the sacramental union.)
Oh, and by the way, I still refuse to speculate. I'll tend my house, thank you, it's far more than I'm capable of on a day-to-day basis anyway.
Now, there is a theory that pride is more an ur-sin rather than a capital sin. That is pride is considered the source of all the other sins.