What is Meditation
While there are many methods of meditation, each each having their own peculiar objectives, approaches, techniques, philosophical assumptions and outcomes,- some common aspects can be outright recognized. Primarily there is a manipulation of faculty of attention. Attention may be directed towards an ideas, sensations, feeling, perceptions, memories, thoughts or even itself. Also the attention may be sustained, dynamic, receptive or exclusive but in every case a modification is exercised. This brings in two more aspects involved intention and exertion.
An unintentional advertence to an object or a group of phenomenon cannot be regarded as meditation till the attention is directed to it intentionally. (Hence quiet often to do something intentionally is even called doing consciousness and something done unintentionally is also called unconsciously. Infact post Buddha the term he used for intention, cetana got confused with consciousness). Intention is essentially action( karma/kamma) and has special role in well being or suffering of individuals and hence pragmatically a very significant phenomenon
As countless events occur in every instance of sensory stimulation and the organism is already deeply conditioned physically and phytologically to react mechanically, the phenomena of exertion becomes relevant and necessary to sustain or direct attention towards a chosen theme and avoid getting dragged by habitual impulses. So while it sounds quiet appealing to have effortless meditation, the phrase only suggests to minimize usage of unnecessary energy( we have finite resources afterall!), any romanticizing beyond that could be easily misleading. Exertion is withholding habitual response and executing intended action.
This naturally brings us to the next key element retention( smriti/sati). Technically every conscious event( not that there are any other kind!), already has intention, attention and exertion yet it cannot be described as meditation (Jhayan/Dhyana). When the three operate with retention, the capacity to bring to mind or hold in mind, then the process of meditation begins. Essentially one has to constantly bear in mind where ones attention ought to be! Retention is poorly understood and hence often translated as awareness, mindfulness or even memory. And while all the terms bear relation to it, they fail to adequately describe its essential nature. The cultivation of this retentive capacity(smaran sakthi/ sati indriya) is key central to the task of meditation ( tough many additional benefits are accrues due to the method chosen as a side effect). Sati in it's essence is opposite to absent mindedness (moha, similar to sammohan or being hyptonised), which is at root of all sorrow and problems of humanity.
There are many other aspects to meditation but the aforementioned are necessary elements to understand the process. Some important aspect are used in only some types of practice. For example if one is trying to develop Insight, they will have to employ faculty of apprehension( sampajanna), this is have an understanding of what is being paid attention to. When many aspects of observed phenomenon are apprehended, in flash of a moment comprehension(Nana/ insight) arises. Some other types of meditations which often but not necessarily aim to calm the mind or seek mystical states often employ thinking(vikkaka/vitark), contemplation (vichara) and manisakar(imagination). The three are powerful tools which can aid in rapid development of retentive capacity.
Lastly some words on awareness( apramaad/hosh) seem due. This is the phenomenon of consciousness which has heightened retention and comprehension starts recognizing itself as knowing. This brings about an ineffable element to experienced as a sense of being here now. This should not be regarded as any mystical quality or unconditioned phenomenon. It is important in that Buddha has called apramaad as door to deathless, bit it must be seen for what it is, consciousness of consciousness.