Thrangu Rinpoche, Pointing Out the Dharmakaya- Chapter 4, pg. 51
The Approaches of Sutra and Secret Mantra (Vajrayana/Tantras)
After we establish the practice of shamatha, we can begin the practice of vipashyana meditation. The reason why vipashyana is necessary to practice is that we undergo a variety of experiences, including the experience of what are perceived as external appearances and the experiences of mental events or inner states, such as mental pleasure, mental suffering, and the various emotions. All inner and outer experiences, without exception, are the confused projections of our mind. These phenomena only appear, they do not exist as we believe they do. To attain enlightenment, it is necessary to have a direct realization of their non-existence. To enable practitioners to accomplish this the Buddha gave various teachings by turning the various wheels of dharma. Essentially his teachings consist of two styles, which we call the sutra and the secret mantra teachings.
Both the sutra and mantra (or tantra) traditions were taught by the Buddha. The sutra teachings consist of a vast body of teachings traditionally classified as 84,000 different collections of dharma; but if we look at them as whole, the main idea presented in the sutra teachings is selflessness, or the emptiness of self. The Buddha presented these teachings gradually and in different stages. His initial presentation, or the first turning of the wheel of dharma, is the presentation of the Four Noble Truths. The essence of this first phase of his teaching is the non-existence of the imputed “self” of persons.
The approach in the sutras then is to develop a conceptual understanding of emptiness and gradually refine that understanding through meditation, which eventually produces a direct experience of emptiness. This approach is very clear, in so far as conceptual understanding is concerned; there is a very clear presentation of the meaning of emptiness. It’s very easy to understand this. At the same time, however, it is very hard to actually meditate upon this, because we are proceeding from a conceptual understanding produced by analysis and logical inference into a direct experience to generate certainty about emptiness. Because we have from the beginning taken inferential reasoning as the basis of our ascertainment, this takes a great deal of time. It is because of this that in the sutras, the Buddha said that to attain Buddhahood takes three periods of incalculable numbers of eons of gathering the accumulations. The reason it takes so long is that we are essentially taking inferential reasoning as our method or as the path. Now, is it necessary for us to undertake such a long and arduous path? It’s acceptable to do so, but there is an alternative, which is the other approach, that which the Buddha taught in the tantras and which was utilized and propagated by the great siddhas.
The Buddha declared that through the practice of the tantric approach, full Buddhahood could be attained in one lifetime and one body. This was the approach taken by the great mahasiddhas who meditated and realized the meaning and attained siddhi in their lifetimes. The instructions for doing this are the instructions of Vajrayana meditation. The primary difference between the sutra approach and the approach of Vajrayana (secret mantra or tantra) is that in the sutra approach, we take inferential reasoning as our path and in the Vajrayana approach, we take direct experience as our path. In the Vajrayana we are cultivating simple, direct experiencing or “looking.” We do this primarily by simply looking directly at our own mind. Both external appearances and our mind are empty in fundamentally the same way. The difference, however, is that external appearances are not obviously empty, so attempting to ascertain the emptiness of external appearances requires us to
fall back on analysis and inference, the sutra approach. But when we’re working directly with our own mind, which is obviously, utterly empty, we have no need for any kind of analysis whatsoever because it is very easy to directly experience our mind’s inherent emptiness.