Neither Isis Unveiled or The Secret Doctrine, nor both taken together unveil all the secrets of nature. Nature contains all.
While she is sensitive to man's prying. She retains her secrets so long as man approaches with a selfish motive, which, being used, might eventually harm both himself and Nature. Most of us are quite unaware of this moral/ethical block.
HPB spoke quite carefully in her introductions to those two books, advising us, her readers that they unveiled sections of what was invisible to most of us. Since she knew that we would be skeptical of all this information, she made it available in gentle steps -- but to grasp it all without gaps, we need to become familiar with all she wrote on behalf of the Great Brotherhood of the Wise, of which she and the Masters of Wisdom are a part.
(She gives evidence concerning this ancient Lodge in Isis Unveiled, Volume 2, beginning on page 98 and running to page 103. If one then turns to page 305 in that book she continues giving information on the subject. See also p. 315, 385, 30-31, 402-404, 470, and Vol. 1, 590-1 -- in fact if these were strung together one would have a grand picture of the breadth of this fact.)
It is not the Names of the claims that are important, but the knowledge that we can use and consider that is valuable. To make this absolutely clear, the concept of Universal Brotherhood (starting on the level of ONE SPIRIT) -- shows our minds that we are already "one in that essence," but also "separate" because of the personal and individual development of understanding (a "mind" encased in a physical form) so essential to the progress of each living "ray" of that ONE, as one of its active "agents" in manifestation.
Once we become aware of the possibility of explaining the very mysterious occurrences that link us to the psychic world of the Astral, we become aware of a continuing interplay. Both religions and sciences are at present still skeptical of the existence of the psychic or astral plane. Religions, because they lose a vital hold over the minds of their parishioners, and sciences, because they cannot explain in detail the phenomena that relate to mind and desire -- which are not easily reproducible.
But science is getting to that understanding by positing the "morpho-genetic field," the "bio-energic fields," "randomness, indeterminacy and chaos Theory," etc... that tend to prove the selectivity and intelligence of the smallest particles of life/matter which they can contact and begin to analyze. Recent experiments in plant sensitivity continue to show their response to the thoughts and feelings of persons who approach them.
Using the Hubble telescope and other analytical tools from Space and outside the distortions of our atmosphere, science has come to see that in the vast Universe "out there" there are similar inexplicable mysteries of existence: such as "Black Holes," "Dark Matter" (or should we call it "transparent matter" as light and other electro-magnetic waves are transmitted through it?), the "Birth of Stars," "Planets belonging to other Suns," etc...
HPB made an introductory statement in 1877 (in Isis) and draw together into once compass the most important statements that opened and unified the many distributed (in many old books scattered in the archives of Universities and National Libraries) accounts of that "invisible world." She used in that presentation classical accounts and current day information and study. She caused a great leap forward in Scientific investigation. (Dr. Thadeus P. Hyatt, a student of HPB's spent a good deal of his spare time in life seeking for the original sources of the references that HPB quoted in Isis Unveiled. This has been published)
Simultaneously a "death-blow" was given to the reserved areas of religious authority all over the world. HPB did not write for the Western world alone, but for all the world and for all the religions and sciences developed everywhere. She dealt not just with our development of science, but with the moral/ethical effects of inventions and discoveries that placed vast and terrible powers (such as the "atomic bomb," and "cloning" and "gene manipulation" -- which is almost on the astral plane -- into the hands of Science.
Her real challenge to us is: how are these powers and knowledge going to be used humanely? Is the mind of mankind to be continually imposed on by those who claim "authority?" Are the pathways to individual inspection, experiment, and learning to be generally opened to those who seek?
She made it clear (but most do not believe her) that the only way to the peaceful, total, and harmonious development of mankind was by cooperation with Nature and not in torturing, distorting and destroying her in whole or in part. What I mean to say is: that only if we give to others weaker than ourselves their rights to habitat and to continued existence, will we succeed in our own personal and collective human existence. "Green Peace," and other ecologically active individuals and bodies, have moved the rather exclusive nature of purely economic considerations to a position of moderation. These along with many others who worry over earth and environment pollution by Big Business and Big Government, are symptoms of this being understood. (At least the politicians seem to realize that their constituents demand that they pay some attention to humane directives in addition to wielding the legislative power they claim that they received as a mandate from their electorates.)
But generally, such considerations are opposed and conquered by the power of the economic market, viewed as a natural war-zone for contending giants in "Big Business," -- to whom the gaining of wealth far outweighs the consideration of the health, welfare and well being of millions of people. Witness the current plight of the "Tobacco Industry," (they deliberately placed addicting drugs in tobacco so that they would gain repeat business and induce dependency on their products.)
Following Isis Unveiled and its success: the sequence of questions, inquiries, additional contributions began -- and those were handled in Theosophist, Lucifer and Path magazines up to HPB's death in 1891. The progress of diffusing Theosophy is important to us, if we follow it, our comprehension widens and deepens rapidly.
The Secret Doctrine was first advertised in Theosophist as a projected amendation of Isis. HPB wrote later that it changed into an entirely separate book. If one reads the exchange of letters between the Mahatmas and Sinnett, Hume and HPB, one can follow the course of that evolution, and in addition, gain insight into the reason for the writing of the S.D.
The S.D. makes it plain that there is an organization to the evolution of the Kosmos, the Solar System, our World and finally ourselves. The unifying link is the MONAD (Atma-Buddhi - a "ray" of the ABSOLUTE -- see S.D. I 570-575) which is the prime cause for "forms" and "beings." It is spiritual, but serves also as a focal point around which the 6 "lower principles" accrete so that by their interaction a bodily form may eventuate.
In the great gamut of beings between Primal SPIRIT (Paramatma) and Primeval "root-Matter" (Mula-Prakriti) there is the link of vital intelligence -- desire and mind (S.D. II 167, 1210, 295fn, 105, 130, 574) That "form" then manifests the level of "intelligence" and progress up the ladder of evolution, of that entity.
Mankind (as beings endowed with the thinking faculty) represents those "Monads" (as a group) which have reached the point (stage) of "self-consciousness." As a group this includes those whose "Manas (mental faculty)" has just been awakened at the "Lighting up of Manas -- some 18 million years ago for us. (S.D. I 150fn, 159, 233, 247-8; II 69, 254, 272) And at the extreme end of the full development of the Mind in that group, lies the INTELLIGENCE and power of the full ADEPT: the MAHATMA, the NIRMANAKAYA, the BUDDHA, etc. (i.e., Those who become responsible for the organizing and the supervision of a new manifestation, and who are the Great Teachers of every World Humanity when it emerges from the equivalent of the "Animal stage" on to the "Human stage" of the "freedom" to chose one's own rate of evolution.).
HPB in The Key to Theosophy and in The Secret Doctrine, and in several of her articles, shows us the rationale for this progression. She indicates, most importantly, that potentially all the powers of the SPIRIT (which unites all) reside in germ in each one of us. (S.D. I 572, 638-9)
The development and the perfection of the human mind leads to that Knowledge -- which eventually turns into Wisdom (as the mind expands in an understanding of all the lines that unite every part of nature to ourselves and to others). The path for us to develop to this level demands that we learn all we can about our own powers and their development and how we can best work in Nature around us. This leads to a perception of active and fundamental BROTHERHOOD.
It leads the independent and free-willed Mind/man to perceive that he needs to so regulate himself and his "Karmic" desire-nature impulses), that he makes himself into a voluntary collaborator with Nature. This voluntary surrender of personal power implies that the "Wise Man" is a collaborator with Nature in all her departments. He sees "Karma" at work and assists. His innate and proven "harmlessness: enables Nature to open the doors of her secret Chambers to him." He will not abuse the privilege.
The thesis is:
This short review of the main teachings and objectives of Theosophy ought to encourage us to delve ever more deeply into the marvelous treasure trove represented by HPB's Isis Unveiled and The Secret Doctrine.
W. Dallas TenBroeck