Philosophically speaking, every society can be categorized based on three aspects: (a) way of thinking, (b) way of living and (c) way of worship. A few examples of each of these are:
  • Way of Thinking: which actions are respectable; who is a good person; which causes should we support, interaction with known and unknown people etc.
  • Way of Living: rituals related to birth, death, marriage; celebrations; dresses to put-on etc.
  • Way of Worship: Nature worship, Idol worship, celebrating natural events etc.
Sanaatan and other Indic darshans [Buddh, Jain, Sikh, and many others] have some commonality in way of thinking and way of living aspects, though there are some variations in way of worship as well as minor variations in way of living. Mostly "way of thinking" is same or very close to each-other.
Sanaatan Dharma has no beginning and no founder. It has adopted universal & eternal spiritual laws as the main philosophy. Its openness and truthfulness enabled its thinkers [called Rishi, Munis] to do research in many disciplines and enshrine the outcome in many books [scriptures], sometimes even appearing contradictory. The Rishis/ Munis, along with their disciples, spent centuries after centuries educating the masses and adopting their customs on the way. 
Many terms used in Hinduism don't have proper English words. Many such terms are defined at: Category:Concise Encyclopedia of Hinduism - Hindupedia, the Hindu Encyclopedia
This section will describe both scripture as well as common knowledge of all Indic Darshans.
         Symbolic Set of Sanaatan Scriptures
Many links, related to Sanaatan Society, including philosophy, are give here.