From the teachings of Khenpo Sherab Depa
Ignorance can be categorized into two types: afflictive obscuration (associated with mental afflictions) and cognitive obscurations which are not associated with afflictions… Desire, anger, stinginess, breaking the precepts are examples related to the afflictive obscurations. On the Sravaka path, one must eliminate the afflictive obscuration entirely to attain liberation (Arhatship).
Even though an Arhat has eradicated all ignorance associated with the three realms, they are still not omniscient. Their knowledge of the nature of all phenomena to be known remains incomplete. This is why the remaining obscuration is called cognitive obscuration (obscuration to knowing).
Only a Buddha who has been through the ten stages (Bhumis) of Bodhisattva path can completely eradicate all ignorance and remove all cognitive obscurations, thus attaining omniscience of the nature of all phenomena to be known.
This discussion leads to the concept of the "Four Causes of Unknowing." In the Wisdom chapter of the Bodhicaryāvatāra (The Way of the Bodhisattva), while refuting Hinayana views over the question of whether the Mahāyāna teachings were taught by the Buddha, these four causes of unknowing are mentioned.
Arhats possess these four causes of unknowing, marking the difference between their wisdom and that of a Buddha. Although the Hinayana tradition holds that through the practice of the Four Noble Truths, one can attain the stage of "beyond learning" (Arahatship), there remains a significant gap between the state of an Arhat and that of a Buddha. The greatest difference can be demonstrated through these four causes of unknowing, meaning that Buddhas have knowledge that Arhats do not. This is also accepted in the Hinayana tradition.
Some aspects of the Buddha’s teachings are too subtle to be grasped even by the Arhats. In the commentary, the example is given of Śāriputra, one of the Buddha’s wisest disciples, who could not comprehend the Buddha’s precept aggregate.
What is this precept aggregate? It refers to the pure precept substance existing in Buddha’s mind. How this precept substance exists in the Buddha’s mind is incomprehensible even to Śāriputra whose wisdom was so profound. This is just one example. The Arhats are unable to comprehend the Buddha’s qualities. This is because an Arhat’s merits are not complete and his obscurations are not entirely extinguished. Hence, he is unable to understand the state of the Buddha and its corresponding qualities and wisdom.
Another example is Mahāmaudgalyāyana (known for his foremost spiritual penetrations or powers) who was unable to discern the rebirth of his mother in the world “Possessing Light”.
Another example is the story of not understanding the qualities of the Buddha’s voice. To give an example, we are listening to the teachings in a classroom. If someone wishes to gauge how far my voice can travel, he will no longer hear my voice just by exiting the classroom. It is like this for an ordinary person. The door obstructs the sound of my voice.
When Mahāmaudgalyāyana attempted to measure how far the Buddha’s voice could be heard, he first travelled to the peak of Mount Meru where he could still hear the Buddha’s voice. Then, using his divine powers and with the help of Buddha's blessings, he teleported himself to many universes away, but he could still heard the Buddha’s voice clearly.
Eventually, he went to the Buddha whose universe he had reached to report his mission. That Buddha asked him, “Why have you come?” He replied, “To check just how far my teacher’s voice could travel.” The Buddha of that universe replied, “The Buddha’s realisation is beyond conception, it is not possible to comprehend it with the Arhat’s wisdom.”
When Mahāmaudgalyāyana finally decided to return, he found himself in a fix. He had travelled so far only with the help of the Buddha’s blessings. The Buddha helped Mahāmaudgalyāyana to demonstrate the inconceivability of the Buddha’s realisation. But now that his own divine powers were exhausted, Mahāmaudgalyāyana could not return on his own. The Buddha of that universe then instructed him, “Think of your own teacher. Face in the direction of your teacher. Prostrate and supplicate.”
Mahāmaudgalyāyana did as he was told and returned back to his own world by the blessings of Buddha Shakyamuni. Therefore, although the Arhat’s wisdom is very high, it has no way of comprehending the Buddha’s wisdom. We find many such cases in the scriptures. This is a clear distinction between the Arhat and the Buddha, even though both fruitions are considered “beyond learning”.
Due to the cognitive obscurations, the Arhat is also unable to perceive events too distant in the past or in the future. When a layman named Palgye wished to renounce the world and become a monk, Śāriputra observed that he had no karma to ordain as he had not accumulated any cause to do so in the past. His request was thus denied. This story is in the Sutra of the Wise and Foolish.
This old man was very sad and started crying. At that moment, Buddha came and said, “I will accept you even if they do not accept.” The Buddha agreed to his request because he saw further into the past than Śāriputra. More than 80,000 eons ago, in one version of the story, this man had once recited "Namo Buddha" planting a seed of merit. Because of this act, the Buddha allowed him to ordain.
The Buddha said that since he had gone through three eons of practice and has now attained the complete mastery of Dharma, it is not Mahāmaudgalyāyana or Śāriputra who knows all the karmic conditions of sentient beings; it is only him, the Buddha, who knows whether sentient beings have the karma to do practice. Śrāvakas can only observe up to 80,000 eons into the past or future, whereas Buddhas can see beyond these limits.
Another case-study shows the four causes of unknowing. Once, when the Buddha and Śāriputra were travelling together, they came across an eagle chasing a pigeon. The pigeon was extremely fearful. However, when the Buddha’s shadow covered the pigeon, it suddenly became calm. But when the Buddha moved on and the shadow of Śāriputra fell over the pigeon, it started trembling again.
Śāriputra found this very strange and asked the Buddha, "Both you and I have eradicated the three poisons (attachment, aversion, and ignorance). Why is it that when your shadow covered the pigeon, it remained calm, but when my shadow covered it, it started trembling again?"
The Buddha replied, "Although both of us are free from the three poisons, the wisdom and merit accumulated through long-term practice are different."
Then the Buddha said, "Try to see how long this pigeon has been reborn as a pigeon." Śāriputra used his wisdom to observe and discovered that for 80,000 eons, this being had always been reborn as a pigeon. However, he could not see beyond 80,000 eons into the past.
Then the Buddha said, "If you cannot see beyond 80,000 eons into its past, try looking into its future."
Śāriputra entered meditative absorption and observed that within the next 80,000 eons, it would still be a pigeon, but beyond that, he could no longer see its future rebirths. At this point, the Buddha revealed to Śāriputra, “I can see clearly into the entire past of this being. Moreover, in the future, after 80,000 eons, it is perfectly clear to me when this sentient being will begin to plant seeds of virtue, when he will first enter the Bodhisattva path and when he will attain Buddhahood.” When the time span is too vast, even an Arhat cannot see, only the Buddha’s wisdom is truly omniscient.
The Arhat is also limited when the causes and conditions are too complicated due to the countless variations or quantities. Take the feathers of a peacock for example. There are many different colors. Each color has its own cause. The Arhat is unable to tell the cause for each color, but the Buddha knows and can discern everything instantly.
The Buddha has eliminated all obscurations to be eliminated. The mind that has eliminated a certain portion of obscurations will give rise to that corresponding portion of qualities or wisdom. Since the Buddha has perfectly eliminated all obscurations, there is nothing left that prevents the complete ripening of all his qualities and omniscient wisdom.
(Note: The Four Causes of Unknowing are:
- Not knowing the Buddha's many qualities
- Not knowing due to distant locations
- Not knowing due to distant times
- Not knowing due to an infinite variety of causes resulting in an infinite variety of results )
