Like I promised, This post is about the origins of Hindu religious culture and Hindu philosophy and the percieved differences between them.
The origins of Hinduism are said to lie in the way of life of the Aryans. There is no central holy book of the Hindus nor are there any founders of the religion.
The earliest written texts which describe this way of life are the Vedas. The Vedas are 4 holy books written sometime between 1000BC and 150BC. The primary contents of the Vedas are a hymns praising the Gods and the Aryan way of life. They also throw light on the social structure of the times. However, the more metaphysical aspects of Hinduism are not made explicit in these texts.
Next we have the Upnishads and the Manu Smriti. These texts came after the Vedas and were more like elaborations and clarifications of the Vedas. Its like people were expanding the basic philosophies and rituals found in the Vedas.
In the Upnishads, we have a much more elaborate description of rituals and expected behaviour of good men. And a lot of philosophical explanation is given for the same.
The Manu-Smriti is another such interpretations of Vedic scriptures. Its more of the same stuff. It lays down the rules, describes do’s and don’t and so forth.
The ritualistc aspects of Hinduism today find origins in the Vedas, the Upnishads and the Manu Smriti.
The last great text is the Bhagvad Gita. This is unique among all the texts as it almost exclusively elaborates on Hindu philosophy. The whole meta-physical concept is at its most developed state in this text. However, It does not discount any of the Vedic rituals or practises. The Bhagvad Gita is like the sophiticated philosophical complement to the ritualistc Vedas and Upnishads.
Now the various Hindu practises like the caste system, The secondary role of women, the aversion to meat except during sacrifices, aversion to onion,garlic etc( coz they spring for impure substances), the various hymns and rites , all spring from the Vedas and the Upnishads. These have evolved into the Hindu culture of today.
The ideas of Hindu philosophy stem mainly from the later Bhagvad Gita and some of the Upnishads. This IMO, is the root of the differences between practised Hindu culture and Hindu philosophy.
In addition to these texts, there are scores of various sects and sub-sects which have been following their own customs and rituals and social structure, presumably ever since Aryan times. And all of these are clubbed under the umbrella of Hinduism since some of the core concepts of karma(fate), dharma(religion), and kartavya(duty) tend to be the same.
I hope this helps in clearing things up.
U can also look at
http://www.sacred-texts.com/hin/index.htm
for some of the sacred texts.