"Toilet God" is not a term I've heard for Tlazolteotl before. The more typical translation being "Filth Goddess," which is a fairly direct translation of " tlazolli" (filth) and "teotl" (deity). Both of those terms, naturally, have additional complexity to them. Tlazolli can also mean something old, worn out, or deteriorated, in addition to its association work excrement. The "filth" implied by the word can also be licentiousness, adultery, and other sexual deviance and debauched living.

Nahua thought is not as manichean as Western theology. Among the Aztecs, few things were strictly "good" or "evil." Instead, the emphasis is on a cycle of transformation, which necessarily entails destruction, decay, or sacrifice in order to ensure regeneration and renewal. Filth could be fertile ground for new life, whether it be the actual night soil used for fertilizer, the rich humus (tlazolalli) in which crops grew, or just a heap of trash attracting all manner of scavengers. The Aztecs recognized that an antiseptic life was not sustainable, that it was incapable of renewal.

With filth being so tied to generating new life it should be no surprise that Tlazolteotl was part of a complex of mother/fertility goddesses, with the fecundity of a woman seen as analogous to the fruitfulness of a field. Her aspect as Ixcuine, in fact, is a direct adoption of the Huastec goddess of cotton, with spinning and weaving being used as yet another metaphor for childbirth and the generation of new life (Sullivan 1982). From this perspective, the sexual energy embodied by Tlazolteotl is not, by itself, a sinful thing, only the over-indulgence in it.

Early Christian friars in Mesoamerica seem to have struggled to impart their notion of “sin” onto the Nahuas. Sigal (2011) notes the dichotomy of good versus evil that in fundamental to Abrahamic theology maps poorly onto Nahua thought, with its emphasis on moderation between austerity and indulgence. The first Christian texts produced in Nahuatl tended to use direct translations for concepts like sin, but not always with the intended effect. The term commonly used, tlatacolli, more literally means something like “the damage done to something or someone.” The confusion of translating abstract notions like sin may have had something to do with friars complaining their Nahua flock often had to be taught what to confess, as their thoughts on what was sinful and worthy of confession did not always line up with the precepts of the clergy.

Nahua morality places much more importance on actions and their intent, as opposed to a Christian framework where someone might “sin in one’s heart.” Because there was not so clear a line between vice and virtue , a Nahua would expect to feel lust, rage, jealousy, etc., but would still be expected to channel their energies into a moderate and prudent lifestyle. A person could lose their way along the narrow path of the good life, but unless they did so intentionally, rather than by accident or by nature of events outside their control, there was not the same onus of guilt.

The Aztec ritual of confessing to Tlaelquani, the “filth eater” aspect of Tlazolteotl, demonstrates the notion of life as a wandering path. The actual term for the act was “neyolmelahualiztli” (straightening of one’s heart), and the penitent was expected to not just confess their misdeeds in life, but to do so in a chronological narrative. Confession was a way of illuminating how a person strayed off and on the moral high road, but was now ready to commit to moral actions for the rest of their life (neyolmahualiztli was only allowed once).

By the mid-17th Century, Christian preachers had started to adapt ideas of Nahua morality into their sermons and teaching texts. Sinning is described in terms of tlazolli imagery, as dirt and dust to be washed off. Confession is translated as “yolcuitia” (to name the heart), a notion not so far removed from straightening it. One area the Christian friars felt they really had a common bond with the Nahua’s, however, was on the topic of sexual sin.

The Fransciscan, in particular, saw the Nahuas as an otherwise upright people who had been led astray by the Devil, with the chasteness of the Nahuas, combined with their harsh punishments for adultery and “sodomy” viewed as evidence of their underlying virtue. This may be a reason why so much post-Contact writing (much of it written by priests) seems to focus almost exclusively on sexual immorality.

There is room to discuss the differences between what Nahuas and Spanish would consider “sodomy,” (which was a rather expansive term at the time), but opprobrium of sexual deviance was not a notion imported by Spanish friars. The Nahuas really did have strict laws against such things as adultery, imposing the death sentence on adulterers. As Nahua thought directly correlated moral health with physical well-being, there was a even a class of diseases whose etiology was sexual misbehavior. The “chahuacocoliztli” (diseases caused by adultery) or “tlazolmiquiztli” (damage/death caused by love/lust) could obviously be caused by someone committing adultery, but also having sex near children, being overly horny in behavior, or even by the strange sexual behaviors of foreigners. Such deviant acts caused the liver to produce an excess of “ihiyotl,” a sort of invisible gaseous energy and part of the tripartite Nahua “soul.” The ihiyotl infected people and caused all sorts of problems ranging from babies being fussy and inconsolable to not being able to cook tamales well. Rituals baths and fumigation of homes (and the guilty party) with incense and herbs were the typical prescriptions to correct the disruption (Baena Ramirez 2012).

Outside of adultery, the other clear cut misbehavior described in the texts is theft. Among the laws set down by Motecuhzoma Ilhuicamina, the majority deal with sumptuary proscriptions, with adultery and theft being the only two criminal acts named. Adulterers were to be stoned to death, while thieves were to be sold into slavery (or killed if the act was severe or repeated).

Advice on good behavior given from parents to children provide another way to determine appropriate moral behavior. The Florentine Codex has a chapter detailing the expectation of a father to his son. For the most part these fall along the idea that a young Nahua man should be diligent and attentive to his duties. There are a total of eight points, the gist of which, given in the King Jamesian language of the translators are:

• Thou art to be one who riseth from sleep

• Thou art to be prudent in thy travels

• Thou art to speak very slowly, very deliberately

• Thou art to pretend not to dwell upon that which is done, that which is performed (i.e., do not pry into the business of others)

• Guard, take care of thy ears, of that with which thou hearest. (i.e., do not gossip)

• When thou art summoned, be not summoned twice, be not called twice

• Thou are not to dress vainly, thou art not to array thyself fantastically

• Above all thou art to be prudent in drink, in food, for many things pertain to it

None of these are particularly shocking, and all are within the overarching ideology of Nahua philosophy, which is chock full of moderation and prudence. The final point is the most interesting, particularly the addendum that “many things” pertain to food and drink. Sexual acts were often placed in the context of “eating” and thus immoderation in consumption applied as equally to sex as it did to tamales and pulque.

This final passage also lays out a Nahua belief underlying the emphasis on male chastity, which was a finite amount of semen. Once a man’s semen was exhausted he was rendered impotent, and thus it was important for a man to delay his sexual life, so that his virility would continue into old age.

Also in this passage is advice about walking the narrow and slippery path of morality:

[Our forefathers] went saying that on earth we travel, we live along a mountain peak. Over here there is an abyss, over there is an abyss. Wherever thou art to deviate, wherever thou art to go astray, there wilt thou fall, there wilt thou plunge into the deep. That is to say, it is necessary that thou always act with discretion in that which is done, which is said, which is seen, which is heard, which is thought, etc.

Overall, the Nahua system of morality is not so hard to grasp, even if it does have fundamental differences from Christian theology. Sacramental and unintentional “sins” were not embraced by the Nahuas, although the sacraments being to a newly imported god might have something to do with that. Mesoamerica generally embraced polygyny to an extent that the Catholics were not comfortable with, but they shared of sex being only acceptable within a relgio-legal framework, even if the Nahuas incorporated polygamy and concuibinage into that frame.

There was even a sort of “original sin” concept (Carrasco 1999). When a child was weaned and took their first bite of solid food, they were ingesting something which was the product of the death and decay it took to produce that food. Simply existing on Earth incurred a cosmic debt because the existence of the world, and everything on it, was the result of not just the sacrifice the gods made to create the planet, but the continuing death and dissolution of every living creature upon the Earth. A Nahua child was born into a world which demanded they be a bulwark against chaos by abstaining from indulgent and extreme behavior in a world that was in constant turmoil and teetering unbalance. That concept, more than a Christian notion of sin, drove Nahua morality.