UdayanaUdayana, (Devanagari: उदयन) also known as Udayanācārya (Udyanacharya, or Master Udayana), (circa 975 - 1050 CE) was an Indian philosopher and logician of the tenth century of the Nyaya school who attempted to devise a rational theology to prove the existence of God using logic and counter the attack on the existence of God at the hands of Buddhist philosophers such as Dharmakīrti, Jñānaśrī and against the Indian school of materialism (Chārvaka). He is considered to be the most important philosopher of the Nyāya tradition.
SamkhyaSamkhya or Sankya (ˈsɑːŋkjə; sāṃkhya) is a dualistic orthodox school of Hindu philosophy. It views reality as composed of two independent principles, Puruṣa ('consciousness' or spirit) and Prakṛti (nature or matter, including the human mind and emotions). Puruṣa is the witness-consciousness. It is absolute, independent, free, beyond perception, above any experience by mind or senses, and impossible to describe in words. Unmanifest Prakriti is matter or nature.
PhilosophyPhilosophy (love of wisdom in ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, values, mind, and language. It is a rational and critical inquiry that reflects on its own methods and assumptions. Historically, many of the individual sciences, like physics and psychology, formed part of philosophy. But they are considered separate academic disciplines in the modern sense of the term.
Āstika and nāstikaĀstika and nāstika are concepts that have been used to classify Indian philosophies by modern scholars, as well as some Hindu, Buddhist and Jain texts. The various definitions for āstika and nāstika philosophies have been disputed since ancient times, and there is no consensus. In current Indian languages like Telugu, Hindi and Bengali, āstika and its derivatives usually mean 'theist', and nāstika and its derivatives denote an 'atheist'; however, the two terms in ancient- and medieval-era Sanskrit literature do not refer to 'theism' or 'atheism'.