Thanks you for sharing your views on the subject.
I'm not convinced that Western Buddhists avoid repentence practice as such. I think the therapeutic or "mindfulness" set does its own thing, in which you won't find much beyond seated meditation and psychotherapy. But people who practice Buddhism as a traditional spiritual path will do repentance practices as par for the course. This is just from my own observation, so I don't have anything empirical behind this claim.
I'd like to know if there are any mainstream Buddhist organizations or prominent teachers that do not advocate some kind of repentance practice, bracketing out the meditation-only set.
You're right, it is too strong to say that Westerners avoid repentance rituals. I have to take that back. Clearly, there are many who do undertake them. I agree with JKhedrup's observation that if the practice is explained properly, it has a better chance of resonating and being undertaken.
Still, and my observations lack any empirical foundation either, it does not seem that repentance gets much emphasis in Western contexts as when I compare practice I have observed in some contexts in Japan (dedication of Jizo statues at some temples, for instance, in connection with abortion is really interesting - so much going on there to unpack touching on so many notions related to repentance in East Asian Buddhism). When it is there in the West, it is treated in a cursory manner. It seems to me, however, to really get into practice, one must go there in depth. Whether you believe your karma is because of causes in past lives or because you were born into circumstances that have left deep and detrimental mental habits that prevent you from perceiving reality as-it-is, examination of one's actions is critical.
I don't think its fair to demand that a literal belief in Mahayana mythology is a prerequisite to enjoying Mahayana practice. I strongly disagree with Rory and his views on faith in Buddhism. Correspondingly, I believe there are ways to present the teaching in a graded manner that does not demand absolute submission to certain views before undertaking beneficial practices.
For me, it still comes back to a question of whether repentance practices can be adapted to those who do not accept Mahayana mythology as literally real?
I don't want to bring up Zhiyi too much as this is a general East Asian forum and Zhiyi is not universally accepted as an authority (although, he is arguably such a giant in East Asian Buddhism that one will almost certainly be defined in some way as either agreeing or disagreeing with him). Nonetheless, I thought his comments about repentance in "Elucidation of the Sequential Approach of the Perfection of Dhyana" might be interesting. In that work he identifies three methods of repentance - 1. repentance involving a fixed regimen of action; 2. Repentance involving the discernment of signs; and 3. Repentance involving the contemplation of [the ultimate truth of] non-arising. The third method would seem to be most useful for a person who does not accept Mahayana mythology. A brief description:
The first involves countering the effects of bad karma with good deeds. In this, Zhiyi includes the Vinaya repentance rituals. "When on confesses [violations] of the second [of the seven] categories [of infraction], an assembly of twenty monks prescribes the particular karma [or "regimen of action"] for removing the sin, such as dwelling apart and submitting to the will [of the monastic community]/ When [the particular] regimen of action has been completed, [the infraction] is declared "eliminated." This [approach] gives no consideration to the perception of different signs or [changes in] demeanor. Nor does it take into account [the presence of] wisdom and the contemplation of emptiness." Sources of Chinese Tradition
, Compiled by de Bary and Bloom, Columbia U. Press, p. 468. You can see the Mahayana bias against Hinayana shining through here, but the point he is trying to make is about a mechanical approach to the purification of karma - the old karma bank where you hope to make more good deposits than bad.
The second involves perceiving signs. While engaged in some sort of Mahayana purification ritual, one will receive some auspicious sign that the efforts have been successful. "Signs [indicating that sins have been eliminated] do not go beyond four basic types: (1) seeing signs in a dream; (2) hearing voices in the air or seeing unusual signs and auspicious spiritual omens while performing ritual circumambulation; (3) seeing signs of [past] good and evil [deeds] or observance and violation of the precepts while one is sitting [in meditation]; and (4) signs indicating such things as the internal realization of various Buddhist teachings (lit., Dharma-gates) or the manifestation of the mind of the Way..." p. 469. Zhiyi warns that true and false signs are difficult to distinguish, and that getting attached to a particular sign will invite "demonic influence."
With regard to the third method, Zhiyi cites to the Sutra on the Contemplation of Samantabhadra: "The ocean of all the karmic obstructions is born entirely from deluded thinking. Should you wish to repent, seat yourself in proper [meditative] posture and fix your mind on ultimate reality. The multitude of sins are like frost and dew: the sun of wisdom can dissipate them [instantly]. Thus, with a heart of utmost sincerity, confess [and repent] the sins of the six sense faculties." He goes on to comment, "All things are originally empty and quiescent. Blessedness itself does not exist; home less does sin? Yet because of their lack of skill in contemplation of this [truth], sentient beings deludedly cling to existence, thereby giving rise to ignorance, craving, and anger. Because of these three poisons, they commit boundless and limitless sins of every description. All of this arises from a single instant of incomprehension [deep] within the mind. If one wishes to eliminate [these evils], one should simply turn back and discern whence this mind itself arises... In this respect, one should realize that "great repentance" refers to profound contemplation of [the ultimate truth of] non-arising. Among the repentances, this form is the most honored and sublime..."
Again, is the point of repentance rituals to reinforce notions of Buddhist mythology in our mind or is it to enable us to remove the obstacles to perceiving the true nature of reality? Zhiyi seems to be saying that awakening to the true nature of reality is the most effective purification practice... One would have to look at what Zhiyi means by true nature of reality... but this is an interesting principal. There seems to be a way to sidestep the whole Mahayana mythology.
Does Mahayana repentance practice necessarily require as a prerequisite that one accept Mahayana mythology as literally true? Based on what a master like Zhiyi wrote, it does not seem to be the case. Realization of non-arising (and non-perishing) would not seem to be affected by views on the "reality", "non-reality" or perhaps more accurately, the Thusness of Samantabhadra.
I'll put this out there just in case - if you are a really pious Mahayanist, you will probably look disapprovingly on me. I believe Mahayana mythology offers an alternate (and superior) vision of enlightenment to the one offered in Pali mythology, or any other model of human awakening, for that matter. I practice according to a mythology I believe expresses the ultimate truth better than others. When I sit down and meditate, I will conjure tutelary deities and interact with them as though they are absolutely real. This does not prevent me from also realizing that I am working within conventions to adjust my habitual mind. No matter how much I have examined it, I can never find the source of Buddhist mythology spontaneously arising in my mind; someone taught it to me. My understanding is that our minds can only think in metaphors; experience of MIND on the other hand... I learned Buddhist mythology, like I learned language. It helps me think and talk about really big ideas that, frankly, I have no other language adequate for the purpose. Maybe I haven't meditated long enough. If visions of Mahayana cosmic heroes have appeared to you spontaneously, I have no doubt about your experience and wish you happy travels on your path. If those experiences are True Reality, I am confident that I will come to them myself eventually. Am I arrogant for seeing things this way? I don't think so. I'm doing the best that I can - I am being honest with myself, and communicating what I see to you, as accurately and as honestly as I am capable.
Regardless, I am confident that we will all converge at the ultimate goal and nod in agreement.