Moral dualism is a view in which there is a strong delineation between good and evil, which in most applicable Eurasian religions is generally symbolized as light versus darkness. The natural result of such a view is often a strong tendency to firmly divide actions and even people into absolute positive and negative categories. One example of this is Christianity, in which humanity constantly struggles between a life in line with God’s commandments and sin. The dichotomy is also drawn between people: there are the virtuous devotees who will enjoy salvation, and the rest of humanity who intentionally or unintentionally side with the enemy of God – Satan – while being condemned to hell.
Moral dualism also often – though not always – goes together with a belief that there is something wrong with the world, in particular the human condition, from which we ought to escape, either through transcending the mundane life while alive, or seeking postmortem salvation in another place away from here.
This is by no means limited to monotheism. Buddhist traditions understand the ordinary human condition as essentially comprised of suffering. The world in which we find ourselves is a result of the collective karma or action of all beings (human or otherwise). This experience of conditioned existence, life after life, is called saṃsāra.
The Buddhist project from the beginning was to escape saṃsāra through wisdom, meditation and renunciation. Later in Mahāyāna traditions, starting especially in the early centuries CE, new beliefs emerged that suggested one could escape saṃsāra through the assistance of benevolent buddhas and bodhisattvas. Although in Mahāyāna one ideal is to become a bodhisattva and actively remain engaged in the world for the benefit of others, the underlying assumption is still that there is something wrong with ordinary existence and all the ups and downs, pleasures and pains, that come with it.
I have observed that polytheist traditions, especially those that are non-prophetic, avoid moral dualism. I have in mind ancient Greek polytheism, but also the various minor cults throughout history that I have studied, from Egypt and the Near East across Asia to Japan. If I may speak in broad and general terms, we see in "classical polytheism" a worldview in which gods and humanity do whatever is in their interests, and in the end the world sorts itself out. There is no absolute right or wrong.
Consider how Zeus overthrew his father Kronos and established his own order; an order that was in the interests of Zeus and his divine regime. Zeus is furthermore not a paragon of virtue. A human society may stand to benefit from entering into a relationship with him, but this requires blood sacrifice and honors to be performed by the people, and just as well Zeus can abandon and harm the people who worship him.
Polytheist traditions might suggest that the gods punish immoral people. At the same time, however, the practice of sacrifice is designed to please and placate the gods, but woe be upon he who angers the gods. In other words, mere mortals can bend the will of powerful gods, if the terms are right. I’ve actually observed this way of thinking in modern Taiwan, where people frequently make offerings and utter sincere requests before gods at shrines. If their prayers are answered, then often the devotee responds by fulfilling their initial pledge, such as making additional offerings. In one case of which I know, a whole new shrine was financed.
These points just illustrate that such a polytheist worldview believes that gods have their preferences and selfish interests, and these might even change over time. This stands in contrast to, for instance, Mahāyāna Buddhism, which considers eminent bodhisattvas – Avalokiteśvara being the most obvious figure – to be basically morally perfected and incapable of malicious acts, deception or selfishness. Avalokiteśvara’s devotees might be flawed people, but the bodhisattva is absolutely good. Ordinary people are encouraged to emulate him, and achieve such moral perfection for themselves as an optimal means of benefiting others.
Bodhisattvas also do not compete with one another, let alone attack each other (in contrast to Zeus and Kronos). An idealized Buddhist world is governed by a benevolent and fully awakened buddha, such as Sukhāvatī in the western direction, supervised by the Buddha Amitābha. Avalokiteśvara, who is part of the retinue of Amitābha, is not expected to ever depose Amitābha, since ideal Buddhist figures are free from mundane ambitions and desires for power.
The polytheist conventions that I mentioned above are also observable in many traditions of ancient magic, in which the mage typically summons spirits and then forces them to do his bidding, which may be entirely selfish and even harmful to other parties. There is no sense in the texts that divine punishment or some impersonal force such as karma will punish those who work magic for worldly gain or the destruction of others (of course, in a culture where magic is widely practiced, an opposing party could just as well direct their magic against you). The comfort of the spirit is also irrelevant, much the same way as the well-being of a sacrificed lamb or bull is irrelevant when a sacrifice is performed to gain the blessings of a god.
I might also point to astrology, which was born out of the Greco-Egyptian environment of Alexandria starting around the second century BCE. Astrology is morally neutral. Someone with rich martian elements in their natal horoscope might be predicted to be violent, competitive and even thuggish, but there is no judgment that condemns this as inherently bad and evil. It is just a result of fate, and fate is the order of things. Similarly, it might be predicted that someone with strong saturnine tendencies in their chart will become a deceptive and gloomy liar, but there is no moral judgement, or even the suggestion that this person might try to reform themselves for the better. Everything has its place in the tapestry of fate. Although there might be measures to negotiate some outcomes of fate, there is no underlying idea that fate is wrong, impure or broken, let alone any notion that one ought to escape from it via some sort of salvation or transcendence.
One sort of duality that one can see in urban societies of the polytheist type is that of order versus chaos. For example, one of the potent myths underpinning Roman imperial dominance was the aforementioned narrative of Zeus (or Jupiter) establishing his order after succeeding Kronos. Dominance and conquest of peoples the Romans considered either barbarian or civilized could be justified by the end result, which was demonstrable peace and order. Operating a lethal war machine and enslaving subjugated peoples to subsidize further expansion and an increase in citizens’ standard of living could be justified without having to refer to a narrative of good versus evil. The end justified the means.
So, returning to Buddhism, does it really subscribe to moral dualism? I’m usually hesitant to speak of Buddhism as a single entity, since it is not and never was, but one continual thread running through all Buddhist traditions is the concept of karma, i.e., action: benevolent actions lead to agreeable results, either in this life or the next, and malicious actions lead to disagreeable results. The moral quality of an action is therefore determined by the state of mind in which the act was executed. Karma is mechanistic and impersonal, so there is no divine law that determines the outcome (however, in practice, Buddhists have often regarded the precepts laid down by the Buddha as sacred laws that should be upheld under penalty of karmic retribution). There is a clear distinction between positive and negative karmas. Moreover, as mentioned earlier, saṃsāra is regarded as painful and wrong, in contrast to the liberated state of nirvāṇa. It stands to state that, very clearly, the idea of karma is dualistic.
Of course, we can point to the concept of upāya or “skillful means”, in which one may carry out otherwise karmically negative acts provided one’s intentions are benevolent. The Yogācārabhūmi, an Indian Mahāyāna treatise, states that even homicide is permissible if it is to save an arhat from being murdered, thereby sparing the perpetrator from falling into the most terrible of hells. There is also in Buddhist thought the idea that intentions may be mixed, and so the resultant effects will consequently be limited for better or worse. However, the ideal is to always have right intentions and to avoid negative karma altogether.
I would also point out that Buddhist soteriology is dualistic in the sense that one prerequisite for liberation is prajñā or wisdom, which is correct awareness and realization of reality and existence. Each Buddhist school has its own ideas about reality and existence, but it is dogmatically assumed that there is one route to permanent, irreversible and complete liberation from saṃsāra, and everyone else is wrong, or at least not 100% correct. It is a battle of wisdom versus ignorance. All the non-Buddhists will eventually, sooner or later, fall back into the lower realms and suffer horribly until they maybe get another chance at true liberation through contact with the teachings of a buddha. Other schools might allow for a yogi to achieve highly advanced states, but that is not true liberation. There is one route to liberation and that is through the Buddhadharma.
The classical polytheist, if I may imagine such a figure, first of all, probably would not see the point in trying to escape the world. Second, he would not have issues with other people’s worshipping different gods. In fact, as has often been the case, he might try to imagine equivalent gods in the other culture similar to his own (in the ancient world, Greek Ares was seen as equivalent to Roman Mars, Iranian Wahrām and Mesopotamian Nergal). The mythologies might differ considerably, but then in the absence of dogmatism and competition between organized religions, there is less need to strictly adhere to one version of mythology.
Interestingly, there are a lot of residual elements of pre-Buddhist polytheism in Buddhist mythology. Just as Zeus overthrew the Titans, so did Indra cast the Asuras off of Mount Meru (both stories stem from the same earlier Indo-European myth). The Asuras climbed up the mountain “like ants going up a pillar”, but were repelled by Indra, who himself was originally a warrior deity.
In the Buddhist view, Indra is arguably not a figure to be emulated, despite his later positive qualities and devotion to the Buddha. This old stratum of mythology is embedded within Buddhist lore as a sort of cultural fossil. While Buddhists were aware of it, their values and sacred narratives were instead based upon the Dharma of the Buddha and successive thinkers and developments.