The fundamental difference between Western philosophy and Indian philosophy, especially the scriptures, is that while Western philosophy tries to uncover the real with the use of the intellect, Indian philosophy is basically an attempt to logically reconcile the world of experience with the spiritual experience of the sages. The sages – Yajnavalkya, the Buddha, Mahaveera – had experienced reality – unlike Western philosophers they’re not speculating, analyzing with the help of reason what reality may be – they know what it is. They have experienced it and using analogies they try to describe it. Indian scholarship is more interested in seeking the ‘fruit’ of Vedic studies, whereas the Western scholarship concerned primarily with the ‘roots’ of the Vedic texts and words.
The scriptures are not to be interpreted as progress in philosophical thought. What’s claimed as polytheism and monotheism is but the identification of the various manifestations of the One Supreme Being. Unity in the Divine is what the Vedic Sages have proclaimed as the highest teaching and numerous verses supporting this are spread across each Veda, from the first mantra portion to the last Upanishad portion: “the One real which the wise declare as many”; “Purusha is all this, all that was and all that will be”; “the real essence of the Gods is one”; “The same real is worshipped as Uktha in the Rg, Agni in the Yajus and Mahavrta in the Saman”; “the indescribable is the ground of all names and forms, the support of all the creation”; “He is immanent in all this creation and yet he transcends it”.
Likewise the different parts of the Veda – Mantras, Brahmanas, Aranyakas and the Upanishads – too don’t signify the progress of philosophical thought. The Veda is a whole package towards spiritual liberation. One cannot directly start with the Upanishads, which teach the highest truth. One must first develop the physical, mental and moral maturity to be eligible to learn such truth. The Mantras, Brahmanas and parts of the Aranyakas serve such a purpose. The four parts of each Veda can also be mapped to the four stages of life (ashrama) of the twice born (dvija). As a student (brahmachArin) one is to chant the hymns and live a life of control and virtue. As a householder (grhasta) one is to observe the injunctions laid forth in the brAhmanas. In the forest dweller stage (vAnaprastha) one is to meditate upon the spiritual truths behind the rituals as explained in the Aranyakas and practice austerity. With the mental and moral maturity developed during the three previous stages one can finally take up the life of a wandering mendicant (samnyAsin) and study the highest truth taught in the Upanishads. Such is the orthodox Indian view.