Old Asian Philosophies
Besides the modern authors, listed above, similar philosophical concepts can also be found in some ancient Asian philosophies, e.g. in the Indian Vedanta.
Vedanta is a philosophy taught by the Vedas, the most ancient scriptures of India. Its basic teaching is that our real nature is divine. God, the underlying reality, exists in every being. Religion is therefore a search for self-knowledge, a search for the God within.
Pavlick, Robert K. (December 2010)
The true Vedantic spirit does not start out with a system of preconceived ideas. It possesses absolute liberty and unrivalled courage among religions with regard to the facts to be observed and the diverse hypotheses it has laid down for their coordination. Never having been hampered by a priestly order, each man has been entirely free to search wherever he pleased for the spiritual explanation of the spectacle of the universe.
Romain Rolland, in Life of Vivekananda (1944)
To get an idea about the vedantic philosophy, you can listen to some talks by Alan Watts, e.g. the first 24 min and 15 sec of the following talk, or by Swami Sarvapriyananda. Both are educated and eloquent personalities, able to explain such advanced philosophical concepts in an understandable and humorous way.