The great positive impact of public health programs is widely acknowledged. Due in part to the policies and actions developed through public health, the 20th century registered a decrease in the mortality rates for infants and children and a continual increase in life expectancy in most parts of the world. For example, it is estimated that life expectancy has increased for Americans by thirty years since 1900,[55] and worldwide by six years since 1990.[56]
These meditations were seen as being supported by the other elements of the eightfold path, such as the practice of ethics, right exertion, sense restraint and right view.[244] Two mental qualities are said to be indispensable for yogic practice in Buddhism, samatha (calm, stability) and vipassanā (insight, clear seeing).[245] Samatha is the quality of a stable, relaxed and calm mind. It is also associated with samadhi (mental unification, focus) and dhyana (a state of meditative absorption). Vipassanā meanwhile, is a kind of insight or penetrative understanding into the true nature of phenomena. It is also defined as "seeing things as they truly are" (yathābhūtaṃ darśanam). The true nature of things is defined and explained in different ways, but an important and unique feature of classical Buddhism is its understanding of all phenomena (dhammas) as being empty of a self (atman) or inherent essence, a doctrine termed Anatta ("not-self") and Śūnyatā (emptiness).[246][247] This is in sharp contrast with most other Indian traditions, whose goals are founded either on the idea of an individual soul (atman, jiva, purusha) or a universal monistic consciousness ( Brahman). Vipassanā also requires an understanding of suffering or dukkha (and thus the four noble truths), impermanence (anicca) and interdependent origination.
One of the best known early expressions of Brahmanical Yoga thought is the Yoga Sutras of Patanjali , the original name of which may have been the Pātañjalayogaśāstra-sāṃkhya-pravacana (c. sometime between 325 - 425) which some scholars now believe included both the sutras and a commentary.[129] As the name suggests, the metaphysical basis for this text is the Indian philosophy termed Sāṃkhya. This atheistic school is mentioned in Kauṭilya's Arthashastra as one of the three categories of anviksikis (philosophies) along with Yoga and Cārvāka.[130][131] The two schools have some differences as well. Yoga accepted the conception of "personal god", while Samkhya developed as a rationalist, non-theistic/atheistic system of Hindu philosophy.[132][133][134] Sometimes Patanjali's system is referred to as Seshvara Samkhya in contradistinction to Kapila's Nirivara Samkhya.[135] The parallels between Yoga and Samkhya were so close that Max Müller says that "the two philosophies were in popular parlance distinguished from each other as Samkhya with and Samkhya without a Lord."[136]