Here, by evolution, we do not mean scientific or Darwinian evolution, which can be regarded as horizontal evolution in a historical sense. We mean evolution in a vertical, transcendental sense, where life, objects, etc. arise from the underlying substratum. Scientific evolution is in the realm of time; the evolution we are referring to is in the realm of the timeless.
There is an individuating principle that generates the myriads of objects in the universe. In Sanskrit it is called kala. This causes the potential inherent in the underlying consciousness to accumulate at a point called the bindu. It is from this point or seed that an object, animal, human being or whatever, can evolve, manifest or grow. Each and every object, big or small, has a bindu as its base. This bindu is hiranyagarbha – the golden egg or womb of creation. It is through the bindu that the immanent and the transcendental merge together.
Bindu contains a blueprint of all the characteristics of the object to be evolved. That which previously had no shape assumes shape through the bindu. The nature of the evolved object is fixed by the blueprint of the bindu.
The bindu is both the means of expression of consciousness and also the means of limitations. Some of the objects will be conscious centres, as in the case of man; most centres will be unconscious, such as elements, stones, etc. The faculty to be conscious or unconscious depends only on the nature of the apparatus of the individual object; this is determined by bindu. Man has the apparatus that allows him to be a conscious centre.
Every object, conscious or unconscious, is intimately linked to the very essence of consciousness through the intermediary of the bindu. Every object evolves into material existence through the medium of the bindu; conversely, every object is withdrawn to the source via the bindu. Bindu is a trapdoor that acts in both directions. It is also the means through which certain conscious centres, such as man, can realize the totality of sahasrara the whole (poorna). There are basically two types of humans: those who are on the Pravritti path and those who are on the nivritti path’ The pravritti path means that man is looking away from bindu towards the outside world. He is almost entirely motivated by external events. This is the path that most people in the world are now treading. It is the path that leads to bondage and away from self-knowledge. The other path, the nivritti path, is the spiritual path, the path to wisdom. It implies that the individual is starting to face the bindu, that he is starting to tune in with the source of his being. It is this path that leads to freedom.
The path of evolution is the pravritti path of manifestation and extroversion. The path of involution leads back along the path that produced one’s individual being; it leads back through bindu to sahasrara. The whole purpose of yoga practice is to direct one’s awareness along the path of involution.