The paths I have mentioned are doctrinal paths, and they must be followed to provide a sound foundation before Tantrayana (the way of Yogic Method) is practiced. In Tibet the greatest care was taken before any Tantric doctrine was introduced. Spiritual teachers always investigated whether the doctrine was among those preached by Lord Buddha, and submitted it to logical analysis by competent Pandits, and also tested its effects in the light of experience, before they confirmed its authenticity and adopted it. This was necessary as there were many non-Buddhist Tantric doctrines which are apt to be confused with those of Buddhism because of superficial resemblances.
The Tantrayana falls into four classes, and it has a vast number of treatises which cannot be enumerated here. In the simplest terms, this is its system: as already explained, bad Karma are held responsible for the various kinds of miseries we suffer. The bad Karma are created through delusion. Delusion is essentially due to an undisciplined mind. The mind should therefore be disciplined and controlled by exercises that stop the flow of evil thoughts. This flow may be stopped, and the wandering of projecting mind brought to rest, by concentration on the physical make-up of one's body and the psychological make-up of one's mind.
The mind may also be focused on external objects of contemplation. For this, strong contemplative powers are needed, and the figures of deities—it has been found—the most suitable objects. For this reason, there are many images of deities in Tantrayana. These are not arbitrary creations. Images, as objects of contemplation to purify the body, mind and senses have to be created in wrathful as well as peaceful aspects, and sometimes with multiple heads and hands, so that they suit the physical, mental and sensuous aptitudes of different individuals striving for the final goal.
Progress towards this goal is achieved in some cases mainly through strong faith an devotion, but in general it is achieved by the power of reason. And if the transcendental path is systematically followed, reason itself will provide during the pursuit many causes for heartfelt belief.
By H. H. the Dalai Lama of Tibet