Philosophical: The word “philosophy,” like so many terms it itself employs, has a wide and undisciplined set of meanings.  PB's philosophy is truly a love (philo) of wisdom (sophia); more, it is the melding of love and wisdom—the ‘jewel in the heart,’ which requires an absolute balance of inner and outer development, if it is to be realized.  Spiritual Philosophy is the loving experience of reverence for (and from) our higher Self; it is the capacity to extract lessons from our own lives; it is the challenge of acting wisely in a world continually obscured by ignorance; and it is the opportunity to know the deepest principles of oneself, the Divine, and Absolute Mind.

In these writings PB lifts our awareness beyond the small scope of our own spirituality into the infinity of the World-Mind and Mind Alone.  He makes it clear that we can and must become sensible of these impersonal mysteries if we are to fully appreciate the reality into which we are born.  PB avoids the labyrinth of religious beliefs and the high-flying theories that so often pass for philosophy these days; instead, he gives us the fundamental realities, stripped of dogma, vital to our lives, and essential to the welfare of the world.   Philosophy is the search for the living Truth, and a steadfast awareness of the Mystery beyond Truth. It requires the full engagement of every faculty and resource we have, and must permeate every waking—and sleeping—hour of our day.  After all, the Truth itself is all-pervasive and unaffected by any limiting condition, and anything which is capable of receiving the Truth must be the same.  Thus it comes to pass that our pursuit of the truth is not finished until our own consciousness—our own higher Self—is bound over to that Truth, once and for all.  When this has happened, the individual has completed the phase of Philosophy and has entered the highest stage known to humankind—Enlightenment.
Here is PB’s own statement regarding philosophy: “Viewed from the standpoint of the house in which we all have to live—that is, the body—Advaita Vedanta seems to deal only in ultimate abstractions—however admirable and lofty its outlook.  The body is there and its actuality and factuality must be noted and, more, accepted.  This is why I do not give any other label to the ideas put into my later books than the generic name philosophy.  I do not call it Indian philosophy since there are ideas in the books which do not belong to India at all.  I do not identify it with any particular land, race, religion, or teacher from the ancient past or the modern present.  Philosophy cannot be limited only to abstract ideas.  It includes those ideas but it also includes other things.  Its original Greek meaning, "love of wisdom," concerns the whole of man, and not only his abstract thoughts, intellect, feelings, body, or relation to the world around him.  It concerns his entire life: his contacts with other people, the morality which guides him in dealing with them, and finally his attitude towards himself.  Philosophy must be universal in its scope; therefore, it may embrace ideas which originate not only in India or in America or in Europe, but in every other period of civilization.  Not all ideas are philosophical, but only those which are true, useful, in harmony with the World-Idea, and able to survive the test of practice and applicability.”
(The Notebooks of Paul Brunton, Category 20: What Is Philosophy? > Chapter 1: Toward Defining Philosophy > # 128)

Books to read:

The Quest of the Overself - This book is an expanded and rational development of Ramana Maharshi’s “Who Am I?” practice, and the book as a whole can be used as an instrument for deepening one’s inner quest.  Mastering this meditation—by way of ‘finding’ the answer—is essential to the philosopher’s work.  After all, if we don’t know our own truth, how can we hope to comprehend universal truth?  The final chapters of this book contain extraordinary descriptions of the presence, power, and Grace of the Overself—words that will bring peace in times of doubt, and clarity in times of peace. 

The Wisdom of the Overself - Where The Hidden Teaching Beyond Yoga teaches us to examine and recognize the full potential of our own mind, The Wisdom of the Overself teaches us to look at the cosmos around us in the same light—as World-Mind, Itself the active phase of Mind Absolute.  While it is possible to read and understand this book in its own right, a careful study of this text will require familiarity with Advaita Vedanta and Buddhism—and at least a passing acquaintance with western scientific thought.  The questions and affirmations presented to us in this text, when illumined in meditation by the light of the Overself, will literally transform our mind and heart into organs of spiritual philosophy.  The Wisdom concludes with a collection of remarkable meditation exercises specifically designed to explore the four states of consciousness—meditations at once immediately useful and yet requiring a lifetime to complete.

The Notebooks of Paul Brunton:
8. The Ego (Volume 6) - Even as we dealt with a study of the ego in the Mystical and Epistemological phases, we must continue dealing with it!  To seek the Truth, to seek the philosophic life is also to seek to put the ego in its final state—as the well-disciplined servant of the Overself.  So long as we’re unenlightened, so long must we be aware of the role of the ego in each successive phase of the practice.  With each advancement, the power of the ego grows, not diminishes—albeit that growth is more subtle and more refined.  It is only when the final battle between the ego’s potent drive towards ignorance and the World-Mind’s Grace has been completed that the ego will bother us no more—and of course, this state is none other than that of Enlightenment.
12. Reflections on My Life and Writings (Volume 8) – This category is largely autobiographical, and includes PB’s reflections on his own writings.  It begins with his reflections on the place of philosophy in modern times, and explores the challenges of finding, sharing, and living with the Truths that philosophy unveils as we progress.  PB uses himself as an example throughout this category—an example that gives us a tiny glimpse into his life, and that can function as a very practical guide for our own.
20. What is Philosophy? (Volume 13) - This category contains PB’s thoughts on Philosophy proper, the experiential philosophy of the world-wise mystic, not the world-weary thinker.  Naturally, there are many overlaps between PB’s view of philosophy and that of the other great sages and traditions of the world.  PB’s emphasis on being balanced is original to himself, and very appropriate for the current era. He even recommends that we are relaxed about how balanced we are—that any practice or technique is, after all, not the “goal” of philosophy.  Indeed, there is no goal for PB…the road goes ever on; it is merely better illumined by the insight of the sage, who continues to journey, learn, and progress throughout eternity—for the Overself is not finite, nor need it relinquish its presence in manifestation to be fulfilled.  Thus for PB the engagement with philosophy is the origin of the royal road upon which the sage forever travels, a road that starts at our front door, a journey that has already begun within our mind and heart, whether we are aware of it or not.
23. Advanced Contemplation (Volume 15) – Although the pursuit of philosophy often begins as an intellectual effort, and is the natural development of studying epistemology, for PB it includes the deepening of mystical practice, as well as learning to be well-grounded in the world.  The first half of this category—the engagement with the Short Path will have already been undertaken in the Mystical phase of one’s quest; now it is time to immerse oneself in the challenges of advanced meditation, including those to be undertaken at the borderland between waking and sleep.  Indeed, there are even some practices mentioned here, and in The Wisdom of the Overself which must be done while one is asleep!  There is also a section on meditation on the void, which culminates in Nirvikalpa Samadhi.  What is remarkable is PB’s advice not only on how to enter that unique state, but how to re-enter the world after such an experience—an experience that is truly an earthquake in the psyche, and therefore quite dangerous for the unprepared.  PB concludes this category with a beautiful section titled: “Why Buddha Smiled” which describes the joy as well as the compassion which is awakened by these deep meditative states.
24. The Peace Within You (Volume 15) – This category naturally follows upon the previous one, and more or less picks up where that one leaves off—with the ‘smile of the Buddha.’  This category is about making the organic transition from glimpses and profound meditations to the quotidian state of illumination enjoyed by the sage.  While many of these paras can—and should—be read at any stage of the Quest, they are primarily meant for those who have passed through the terrors of the Dark Night of the Soul, the momentary annihilation of the ego in Nirvikalpa samadhi, and for whom the Short Path is no longer an option but a necessity called for from within.  To such advanced mystical philosophers, the time of enlightenment is near (albeit it may yet be a lifetime away); this is a time of waiting and subtle growth, requiring patience and providing a phase of respite before the final assault—the complete bonding to the Overself in Being, and not in becoming.  As one reads these paras, they should be allowed to send down their roots into the depths of the psyche, and slowly transform the totality of the individual into a proper agent of the Overself, nothing more, and certainly nothing less.