On a few occasions when asked about meditation, Guruji quipped: "What? Mad attention!"
Westerners can be justified in their confusion about the very specific use of the word dhyana (translated as meditation) in the context of Patanjali's yoga. In the West, meditation can be taken to mean absorption or reflection with a non-specific level of attention. In Patanjali yoga, dhyana forms a central role in a triad of internal functions leading to the ultimate state. According to Patanjai, dharana (concentration), dhyana and samadhi are linked - one leads to the next. He calls this process Samyama. Samyama is used in all the stages of samadhi.
Guruji's response was probably to the question of a naive new student, someone who had perhaps explored some new age guided meditation. "You have no idea what you are asking about!" is what he meant. Ashtanga Yoga is a step by step method - first you have to purify your body and mind and then it will make sense to sit, otherwise your attempts at meditation will produce "mad attention" - total distraction. Guruji did teach meditation and mantras on an individual basis to his students, so he was not of the opinion that meditation was a waste of time for Westerners.
At the end of practice there is a natural opportunity to sit in padmasana for a longer period of time and many students naturally start to include some meditative elements in their practice at this point. Some students are attracted to chanting, others to pranayama, others integrate meditations they bring from their own traditions. Vipassana is very common amongst ashtanga practitioners and seems to make a very good partner in the connection through breath.
For most students it takes many years to feel ready to properly explore the internal limbs but some very few do not even need asana practice. For many ashtanga practitioners, pranayama is the gateway to the internal and leads naturally to the succeeding limbs.
Dharana - Dhyana - Samadhi - Samyama
Concentration, dharana, is a function of our day to day life. We are always trying to concentrate, so even though dharana is called the first internal limb, it may be found as part of everyday life. I am not suggesting that dharana is easily mastered, just that it is something of common experience.
The practice of dharana involves keeping the attention fixed on one object for a period of time. The mind has distractions, but it is repeatedly brought back to its object. These distractions are accepted within the definition of dharana. Patanjali suggests concentrating on different points of the body, a practice which is elaborated in the Yogayajnavalkya Samhita.
According to Guruji, dhyana which follows from dharana is a natural outgrowth of purifying the mind through yoga.
There are sixty-four yogic arts through which meditation and samadhi can be experienced. Any one who has gained some mastery over a musical instrument can attest to the way in which the mind shifts from a state of concentration to a state in which the mind merges with the music. Dharana is likened to the individual droplets which form when when water is poured from a vessel, in contrast dhyana is likened to the pouring of oil - no droplets (discrete thoughts) form, there is a merging of thoughts into a single flow in the direction of the object.
Patanjali says, if you are having trouble fixing the mind in Samadhi, then you should meditate - he says any suitable (appropriate) object may be used.
The practice of samadhi is to merge the mind completely with an object. The ideal object (subject) is the Self. The Self cannot be witnessed or described, it has no attributes, so its manifestation arises when the mind becomes attribute-less, when the mind dissolves, finds total quiescence. There are numerous meditations which may lead to the mind's dissolution and the resulting Samadhi. Some are gradual, some are direct, but success, of course, depends on the readiness of the subject.
Apart from following the limbs of yoga, success will only come to one who lets go of worldly desire. So long as desire persists, it will act as a distraction in meditation. Guruji spoke a great deal about practice, but much less often about vairagya. Patanjali says, these two, not just practice, but practice and moving the desire for the external towards an internal goal, will lead to chittavritti nirodhah.