Men vary in capacity, temperament, knowledge and general advancement, and therefore the means (for Sadhana also means instrument) by which they are to be led to enlightenment must vary. Methods which are suitable for highly advanced men will fail as regards the ignorant and undeveloped for they cannot understand them. What suits the latter has been long out-passed by the former. At least that is the Hindu view. It is called Adhikara or competency. Thus some few men are competent (Adhikari) to study Vedanta and to follow high mental rituals and Yoga processes. Others are not. Some are grown-up children and must be dealt with as such. As all men, and indeed all beings, are, as to their psychical and physical bodies, made of the primordial substance (Prakriti-Shakti), as Prakriti is Herself the three Modes of Nature (Gunas) – light (Sattva), dynamism (Rajas) and sluggishness (Tamas) – and as all things and beings are composed of these three Modes of Nature in varying proportions, it follows that men are divisible into three general classes, namely, those in which the Sattva, Rajas, and Tamas Gunas, predominate respectively. There are, of course, degrees in each of these three classes. These three classes of temperament (Bhava) are known in the Shakta Tantras as the Divine (Divyabhava), Heroic (Virabhava) and Animal (Pashubhava) temperaments respectively.
– Arthur Avalon (Shakti and Shakta)