➥ bojjhaṅga: 'the 7 Factors of Enlightenment', are: Mindfulness (sati-sambojjhaṅga; see sati), investigation of the law (dhamma-vicaya-sambojjhaṅga), energy (viriya-sambojjhaṅga; see viriya, padhāna), rapture (see pīti-sambojjhaṅga) tranquillity (see passaddhi-sambojjhaṅga), concentration (see samādhi-sambojjhaṅga), equanimity (see upekkhā).

“Because they lead to enlightenment, therefore they are called factors of enlightenment” SN 46.5

Though in the 2nd factor, dhamma-vicaya, the word Dhamma is taken by most translators to stand for the Buddhist doctrine, it probably refers to the bodily and mental phenomena (nāma-rūpa-dhammā) as presented to the investigating mind by mindfulness, the 1st factor. With that interpretation, the term may be rendered by 'investigation of phenomena'.

In AN 10.102, the 7 factors are said to be the means of attaining the threefold wisdom (see tevijjā).

They may be attained by means of the 4 foundations of mindfulness (see Satipaṭṭhāna), as it is said in SN 46.1 and explained in MN 118:

(1) “Whenever, o monks, the monk dwells contemplating the body (kāya), feeling (vedanā), mind (citta) and mind-objects (dhammā), strenuous, clearly-conscious, mindful, after subduing worldly greed and grief, at such a time his mindfulness is present and undisturbed; and whenever his mindfulness is present and undisturbed, at such a time he has gained and is developing the factor of enlightenment 'mindfulness' (sati-sambojjhaṅga), and thus this factor of enlightenment reaches fullest perfection.

(2) “Whenever, while dwelling with mindfulness, he wisely investigates, examines and thinks over the law … at such a time he has gained and is developing the factor of enlightenment 'investigation of the law' (dhamma-vicaya-bojjhaṅga) ….

(3) “Whenever, while wisely investigating his energy is firm and unshaken … at such a time he has gained and is developing the factor of enlightenment 'energy' (viriya-bojjhaṅga) ….

(4) “Whenever in him, while firm in energy, arises supersensuous rapture … at such a time he has gained and is developing the factor of enlightenment 'rapture' (pīti-bojjhaṅga) ….

(5) “Whenever, while enraptured in mind, his body and his mind become composed … at such a time he has gained and is developing the factor of enlightenment 'tranquillity' (passaddhi-bojjhaṅga).

(6) “Whenever, while being composed in his body and happy, his mind becomes concentrated … at such a time he has gained and is developing the factor of enlightenment 'concentration' (samādhi-bojjhaṅga).

(7) “Whenever he looks with complete indifference on his mind thus concentrated … at such a time he has gained and is developing the factor of enlightenment 'equanimity' (upekkhā-bojjhaṅga).

Literature: Bojjhaṅga Saṁyuttā (SN 4); Bojjhaṅga Vibhaṅga - For the conditions leading to the arising of each of the factors, see the Commentary to Satipaṭṭhāna Sutta (Way of Mindfulness, by Soma Thera; 3rd ed., 1967, BPS). Further, The 'Seven Factors of Enlightenment', by Piyadassi Thera (Wheel 1.)