Definition of Sanātana-dharma
Sanātana-dharma is a conglomerate of all laukika-dharmas like the mātṛ-dharma, pitṛ-dharma, rāja-dharma, strī-dharma, prajā-dharma + all vaidika dharmas like the varṇāśrama dharma + puruṣārthas like dharma, artha, kama, moksha & prema + paths like karma-kāṇḍa, jñāna-kāṇḍa, upāsanā-kāṇḍa, aṣtāṅga-yoga + darśanas like the Vedānta, Nyāya, Mīmāṁsā etc. + upāsanāgata sampradāyas like śaiva, śākta, gāṇapatya, saura, vaiṣṇava, nirguṇa-brahmavādī + dārśanika sampradāyas like viśiṣṭādvaitī, dvaitādvaitī, kevalādvaitī, śuddhādvaitī, dvaitī, acintya-bheda-abheda-vādī etc. + śrutis, smṛtis & āgamas. When all such is combined, the aggregate is known as Sanātana-dharma. The basis of such Sanātana-dharma are – go-mātā (Mother Cow), brāhmaṇas and vedādi-śāsstras (this includes prasthāna-catuṣṭayī viz., Upaniṣads, Brahma-sūtra, Śrīmad-bhagavad-gītā and Śrīmad-bhāgavatam along with Itihāsa/Mahābhārata, Kāvya/Mūla-rāmāyaṇam, Pañcarātrāgama etc. & smṛtis like Manu-smṛti, Yājñavalkya-smṛti etc.).
Concurrent philosophical discord (the diverse views of all sects need to remain diverged in order for them to retain their peculiar status and the Sanātana-dharma is never monotonous+ continuous analysis of all diverse philosophical stands is, absolutely, necessary for the healthy growth and continuity of any religion and the resultant affiliated spirituality, for if theological notions go unchallenged — no harm is more detrimental than such in the highest metaphysical context) among the Sanātanī sects + social concord (social and political unity against the non-Vedic and esp. non-Indigenous Abrahamic faiths) among the various Sanātana-dharmī sects is the only solution.
Socio-political concord while facing a common enemy can co-exist along with a metaphysical and philosophical discord internally and this diversity does not lead to any sort of criminal vandalism — such is the peculiarity of Sanātana-dharma and its internal sub-sects — not at all to be seen anywhere else (in other denominations – Abrahamic). So far as the epistemological methodology adopted by various sects of Sanātana Vaidika Dharma is concerned, Vedas, as a common ground are accepted as mūla-pramāṇa and svataḥ-pramāṇa by all Sanātanī sects. All sects of Sanātana-dharma need to be made prosperous so long as they are committed to follow the common ground of Vedic validity. Such is our opinion. Diversity within Sanātanī sects does constitute its opulent gorgeousness. They are required to not let monotone peep in. Hence, variety is a must. Such variety can, only, further grow, if philosophical criticisms and discords prevail. Otherwise, in absence of criticisms and philosophical discords, again, such pre-existent diversity will turn monotonous.
— Gurupādācārya Svāmī