Formal cooperation occurs when the act of another person is intrinsically evil, and your cooperating act is ordered toward assisting the act of the other person (the perpetrator) in attaining its evil moral object (the end of the intrinsically evil act). For example, if the act of perpetration is abortion, and the cooperating act is to legalize or broaden the legalization of abortion, then the cooperators — legislators who vote for the law — are guilty of formal cooperation.
The sin of formal cooperation is always intrinsically evil, as it is nothing other than an act ordered toward the accomplishment of another intrinsically evil act. And intrinsically evil acts are always objectively immoral. When the act of perpetration is gravely immoral, the act of formal cooperation is also gravely immoral.
If a woman obtains an abortion, that is one gravely immoral act. If a Catholic author publicly approves of, justifies, or rationalizes, certain direct abortions or the use of abortifacient contraception while sexually active, then that author commits formal cooperation with the type of murder called abortion. Sometimes the act of cooperation is more gravely immoral than the act of perpetration. An author might influence thousands of persons to commit abortion or to use abortifacient contraception, thereby cooperating in the deaths of thousands. But the individual who commits one sin of abortion, is guilty of one sin, not thousands.
Catholic authors who justify the use of abortifacient contraception, while sexually active — whether these authors are well-known and writing under their real name, or are unknown persons writing under a pseudonym — are guilty by formal cooperation with the deaths of innocent prenatals, however many deaths are caused by their words. In some cases, as their words continue to be read by more and more persons, they become guilty of many thousands or tens of thousands of deaths.
Now consider what happens with the perverse version of the theology of the body, the version used to approve of all manner of intrinsically evil and gravely immoral sexual acts in marriage (unnatural sexual acts). If an author promotes these acts in talks, or books, or articles, or online posts and discussions, he or she is guilty of formal cooperation with perverse and degrading sexual acts, and these acts also offends against the Sacrament of holy Matrimony, as a type of sacrilege. Then, however many marriages and souls are harmed by their words, that is the measure of their offense of formal cooperation.
Gregory Popcak is guilty of formal cooperation with fornication, since he says that he works with unmarried couples, helping them obtain more enjoyment from the sexual acts outside marriage. And he is guilty of formal cooperation with the unnatural sexual acts he promotes and approves within marriage. It may be that his words will, when all is said and done, have harmed millions of souls. And when finally he is judged by God, all these sins will be charged against his soul: formal cooperation with millions of exceedingly wicked sexual acts.
Other authors are also guilty, perhaps to a lesser extent if their words reach fewer persons. But they are guilty nonetheless. And the number of gravely immoral acts, with which they are guilty of cooperating, is still an immense burden for any soul. Publicly approving, promoting, and encouraging unnatural sexual acts in marriage is a wicked act, which should prohibit these persons from reception of Communion. For they are obstinately persevering in manifest grave sin by the public approval of unnatural sexual acts in marriage. But in the Church today, so many Catholics commit so many gravely immoral sexual acts, no one seems to notice these wicked type of formal cooperation.
The worst of these authors, who are guilty of harming millions of souls by promoting gravely immoral sexual acts, have a greater guilty than some pornographers. For they not only harm just as many souls, but they do so under the pretext of teaching the Gospel of Jesus Christ, the pretext of explaining holy acts, and as a sacrilege against Sacrament of holy Matrimony. It is worse to commit a grave sin under the guise of teaching Christianity, than it would be to simply commit the sin openly.
In the Old Testament law, a thief was punished more than a robber. A robber fears neither God nor man, since he commits his crime openly. But the thief has a greater disorder in that he fears man, but does not fear God.
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