Lonergan and the Surd of Contraception

David Fleischacker, PhD, December 2008 (written 10 years ago)

In 1943, Lonergan had written an essay on marriage, love, and finality.[1] In this essay he makes use of metaphysics to develop the intelligibility of marriage and family in such a manner as to provide a systematic understanding of the Church’s teaching as it had been developed in Casti Connubii. He intended on the essay to become a springboard for a larger exploration of the meaning of marriage and family. The key metaphysical analogy used in the essay is that of finality.


Lonergan distinguished a variety of types of finality, two of which were central for the issue at hand, namely horizontal and vertical. They are key in understanding the hierarchy of being and the good. They are also important for developing an understanding of the distinction and relationship of all fields of knowledge from physics to theology. They are important for understanding human reality as well, especially as an embodied interiority in which the body has its own horizontal ends, but is vertically related and integrated into motor-sensory experience, understanding, knowledge (level of judgment), the will (level of decision), and supernatural life.

Thus, it has a place in marriage as well. Horizontal and vertical finality are key for understanding the essential (procreative) and excellent (unitive) ends of marriage. Lonergan writes in 1943 that

If then, reason incorporates sex as sex is in itself, it will incorporate it as subordinate to its horizontal finality of sex much more than of sex itself; nor is this to forget vertical finality, for vertical and horizontal finalities are not alternatives, but the vertical emerges all the more strongly as the horizontal is realized the more fully (Collection, 46).

This presents an important fact about horizontal and vertical finality. One cannot have vertical finality without the realization of horizontal finality. The above quote is part of a paragraph that was explaining the relationship of sex and marriage. Lonergan started the paragraph by claiming “marriage is a rational form, the incorporation on the level of reason, not of the child nor of the fecundity of the parents, but of sex and of the finality of sex to the child.” Then, a few sentences later, he wrote “marriage is more an incorporation of the finality of sex than of sex itself” (45). That finality was the horizontal finality of sex (male and female fecundity in conjugal union) to the generation of a child. It is intrinsically oriented toward the creation of a child. To remove this horizontal finality of sex and the conjugal act is to eliminate the vertical meaning as well.

This point explains why in Catholic doctrine consummation is so important for the sacramental bond and its indissoluble state. It explains the unique relationship that men and women have to each other in such a context. It also explains why contraception would be an act against the finality of sex, first against the horizontal, and subsequently against the vertical as well.
In later writings, Lonergan only strengthens and refines his understanding of horizontal and vertical finality, especially in INSIGHT, where he integrates conjugate forms and their statistical realization in schemes of recurrence into a metaphysical account of development in terms of finality. Working through Lonergan’s position on higher and lower levels and their development in terms of horizontal and vertical finality allows for one to comprehend the true unity of the horizontal to the vertical in all fields of science. Eliminate, for example, Kreb’s cycle, and one will destroy the higher organic conjugates of the cell, and any developmental finality of the cell. Eliminate neural processes, and one destroys the vertical existence of the sensate forms and their psychic development.[2]

Lonergan and Marriage

In the case of marriage, eliminate the horizontal finality of the pro-creative schemes of recurrence, and one destroys the unique rational and volitional relationship that emerges and develops between a man and woman. Thus, one does not have the “rational” relationship of a civic marriage without this conjugal relationship. And one does not have the sacred relationship of a sacramental marriage without this conjugal relationship. In initiating and then hindering these procreative schemes of recurrence and their developmental finality, one metaphysically destroys all of the vertical meanings that build upon these schemes.

Thus, Lonergan’s position is not against the teaching of the Church on marriage and family. Quite the contrary. Some of Lonergan’s most significant contributions to philosophy, especially to metaphysics, results in affirming the natural intelligibility of the procreative and unitive aspects of marriage, and the unity of these aspects with each other. The analogy of horizontal and vertical finality provides substantial grounds for making this claim.

This of course, is not a position that some Lonergan scholars have taken regarding the Church’s teaching on contraception. Some had made use of a 1968 letter that Lonergan allegedly [4] had written which questions the Aristotelian basis of the Catholic teaching on marriage, conception, and contraception. However, even if written by Lonergan, careful analysis of the letter does not lead to any definitive position on the issue. If one thinks that a statistical relationship between the conjugal act and conception negates Catholic teaching against contraception one has failed to understand Lonergan on statistics and finality. For Lonergan, statistical probabilities are integral to finality. This may change the Aristotelian view of a natural causality of conception, but in turn, it grounds a deeper understanding of nature that supports both Casti connubii‘s and Human vitae‘s condemnation of contraception even better than Lonergan’s 1943 essay had accomplished. In the end, contraception is just as much a surd as it would be if the Aristotelian understanding of conception were correct. Why? Because initiating the procreative schemes in the conjugal act, and deliberately introducing something that blocks the schemes from completing is against the entire horizontal finality of these schemes and the conjugal act. One is actuating the finality for a child and yet privating that same finality, and thus in the decision to introduce contraception, one is acting against the intelligibility, being, and goodness of the conjugal act and its meaning. This surd privates the emergence of the higher orders that build upon it, thus it not only an essential surd, but an excellent surd (to use those 1943 terms). That is a surd that makes the decision to contracept absurd. Thus, objectively it is an evil, a privation of intelligibility, being, and goodness that should not take place. Thus, to avoid this evil, every conjugal act needs to be open to the finality that it intrinsically possesses.[3]

[1] Bernard Lonergan, “Finality, Love, and Marriage” in The Collected Works of Bernard Lonergan, vol. 4 (University of Toronto Press, 1988), 17 – 25.

[2] Perhaps a better analogy is one derived from adult stem cells. The oocyte and spermatozoa are more akin to stem cells, which then form the embryonic stem cell, which is the beginning then of an embryonic child. Destroying stem cells in the body will destroy the realization of their horizontal finality into mature cell types and thus the organic conjugates that are supported by these developmental sequences. So, if one destroys all of one’s bone marrow, one can no longer generate new blood cells which in turn support all the systems in the body. This in turn will stop the life and development of the motor-sensory levels, which in turn will stop intellectual and moral development.

[3] This also provides a way for understanding Natural family planning as well, and its right uses, though that goes beyond the current point on contraception.

[4] I say “allegedly” because When Dom Sebastian Moore asked Lonergan to whom the letter was written, Lonergan responded that he did not even remember writing the letter. There is no name of the person to whom the letter was address. Also, the letter is not signed by Lonergan. Furthermore, the statement about Aristotelian biology is followed by an overstated conclusion that would be unusual for Lonergan. Finally, there is no mention of the transposition that Lonergan himself made in INSIGHT of Aristotelian heuristics to those of modern biology and the relations between the two.