The word theosophy is one with a long history. It has been used in different traditions and contexts, and consequently acquired a multiplicity of meanings. The term derives from the Greek theosophia (θεοσοφία), which is composed of two words: theos (‘God’, ‘gods’ or ‘divine’) and sophia (‘wisdom’). According to the context and tradition in which this term has been used, theosophia can be translated as the ‘wisdom of God (or the gods)’, ‘wisdom in things divine’, or ‘divine wisdom’.
The person in touch with this theosophia (variously called theosophos (Greek), theosopher, or Theosophist) acquires a knowledge that is not the product of his or her rational faculty. The source of this divine knowledge has been variously considered to be God, a divine being, or a state of inner illumination attained through purification and spiritual efforts.
In its deeper meaning, the concept of theosophia implies that there is in human beings a faculty higher than reason—an “interior principle” or spiritual intuition through which we can reach the Divine Wisdom. In HPB’s words:
But all [sacred] books it [Theosophy] regards, on account of the human element contained in them, as inferior to the Book of Nature; to read which and comprehend it correctly, the innate powers of the soul must be highly developed. Ideal laws can be perceived by the intuitive faculty alone; they are beyond the domain of argument and dialectics, and no one can understand or rightly appreciate them through the explanations of another mind, though even this mind be claiming a direct revelation. 
History and development of the term
The word theosophy has been used in connection with a number of religions and philosophical schools. Although the Neo-Platonic, Christian, and modern Theosophical traditions have used this term more prominently, we can also find references to a Hermetic theosophy, a Jewish theosophy (found in the Kabbalah), a Muslim theosophy (mainly among the Sufis), a Persian theosophy, etc. In this article we will limit ourselves to examine briefly the use of this term among the Neo-Platonists, Christians, and members of the Theosophical Society.
a) The Neo-Platonist theosophos
The origin of the term theosophia is unknown, but it is likely to have been coined by the Neo-Platonists (a philosophical school founded by Ammonius Saccas, who was born ca. 175). Based on the writings of the famous Platonist Prof. Alexander Wilder, Mme Blavatsky suggests that the term was commonly used by all Neo-Platonists.  However, researches made in the late 1980s by scholars James Santucci  and Dr. Jean-Louis Siémons  showed that it is only with the third-generation Neo-Platonist Porphyry (234–305) that we find the term in writing for the first time. In Porphyry’s view, the divine wisdom is a state of illumination that can be attained by self-exertion. The theosophos (Gr. θεόσοφος) tries “by himself, to elevate himself, alone to alone, to a communion with the divine.” With Iamblichus (250–325), the pure mystical meaning given to the term by Porphyry acquires a more occult or magical significance. He proposed that the theosophia can be attained through theurgy (Gr. θεουργία), a series of religious rituals and magic operations aimed at elevating consciousness. Proclus (412–485) uses the term in yet another way to denominate specific spiritual doctrines, making reference to a local ‘Hellenic theosophy’, but also to a foreign or barbarian (that is, non-Greek) theosophy, referring to Chaldean doctrines. [*]
b) The Christian theosopher
Many early Christians, including a number of Church Fathers, were students of Neo-Platonic teachers. They also adopted the term theosophia, but used it in a more Christian sense to mean “the Wisdom of God”. Clement of Alexandria (150–215) talks about a theosophos as one who writes “driven by divine inspiration,” and thus in time this term came to be used to refer to the prophets of old. An important difference between the Neo-Platonic and Christian concepts of theosophia, is that in the former view no one is a born theosophos—he becomes such by long exertion, application to philosophy, self-purification and contemplation of the divine.  In the Christian view the divine wisdom is bestowed by God—as He chooses—upon the prophet, in the form of a revelation. After the Neo-Platonists disappeared in the 6th century, the term theosophia continued to be used in Christianity during the Middle Ages, but frequently in a lower sense as a synonym of theologia. [**] In the 9th century, after the re-discovery of the works of Pseudo-Dionysius (a Christian Neo-Platonist that lived ca. 500) the term regained a lofty meaning among great mystics such as Meister Eckhart, J. Tauler, John of Ruysbroeck, and others. It was through their writings that 17th to 19th century European mystics such as Boehme, Saint-Martin, Swedenborg, and others, inherited the term theosophy and adopted it as their own. With these “theosophers” (as they came to be known) the term became popular, being on the title of a number of books during the 1700s.  There continued to be publications on Christian theosophy until the middle of the 19th century.
c) The modern Theosophist
At the opening of the last quarter of the 19th century a committee formed by Mme. Blavatsky, H. S. Olcott, W. Q. Judge, and others, founded what they called the Theosophical Society. According to Col. Olcott, the choice of the name of the newly formed Society was subject of discussion in the committee, and several options were suggested, such as the Egyptological, the Hermetic, the Rosicrucian, etc. However, none of them seemed the right one. ‘At last,’ he recalls ‘in turning over the leaves of the Dictionary, one of us came across the word “Theosophy,” whereupon, after discussion, we unanimously agreed that that was the best of all.’ Olcott explained this name was appropriate because it expressed ‘the esoteric truth we wished to reach’ and covered the ground of ‘methods of occult scientific research.’ 
It does not seem likely that the name for the Society was chosen merely out of a dictionary search, since Madame Blavatsky had already connected her knowledge with the term theosophy a few months before, in a letter to Hiram Corson:
My belief is based on something older than the Rochester knockings [that began the Spiritualistic movement in 1848], and springs out from the same source of information that was used by Raymond Lully, Picus della Mirandola, Cornelius Agrippa, Robert Fludd, Henry More, et cetera, etc., all of whom have ever been searching for a system that should disclose to them the “deepest depths” of the Divine nature, and show them the real tie which binds all things together. I found at last, and many years ago, the cravings of my mind satisfied by this theosophy taught by the Angels and communicated by them that the protoplast might know it for the aid of the human destiny. 
As shown in a previous article (“What is Theosophy?” The Theosophist, Dec. 2007) Mme. Blavatsky used the term Theosophy with the following meanings:
a) As a state of illumination where the theosophist is in touch with the Divine Wisdom. This, as we have seen, is the meaning used by Porphyry.
b) As a universal Ancient Wisdom, similar to the perennial philosophy of the Renaissance. This idea has been present under different names through a number of philosophers since the beginning of recorded history. Marcelo Ficino and Pico della Mirandola, whose writings influenced Christian theosophers, called this Ancient Wisdom prisca theologia. Essential elements of this perennial philosophy are shared by the different theosophies, the term being applied here as a name for different doctrines, much as Proclus did.
Regarding the word “Theosophist,” although today it is commonly used to refer to a member of the Theosophical Society, since the beginning of the organization its leaders established a difference between a real Theosophist and a member of the TS. While a Theosophist is in touch with the Divine Wisdom, members of the Society are students of the teachings of Theosophists, with the aspiration to develop their “inner senses” so to eventually become a real Theosophist.
On the modern and the Christian theosophies
The modern and the Christian theosophies differ in their language, style, and reference books they use. Modern Theosophy is outside any religious framework. It does not teach the existence of a personal God and does not accept the idea of vicarious salvation. Blavatsky never claimed the Theosophical Society to be a direct continuation of the Christian current. As seen in an earlier quote, the first time that HPB associates herself to the word theosophy she does not mention Christian theosophers but refers to Alchemists, Kabbalists, and Platonists. [***] It is with them that she claims to share the same “source of knowledge.” This does not mean, however, that she identified the modern Theosophy with the mediaeval European esotericism either:
But real Theosophy—i.e., the Theosophy that comes to us from the East—is assuredly Pantheism and by no means Theism. Theosophy is a word of the widest possible meaning which differs greatly in Eastern and Western literature. Moreover, the Theosophical Society being of Eastern origin, therefore goes beyond the narrow limits of the mediaeval Theosophy of the West . . . 
Some scholars feel that H.P. Blavatsky et al. unduly appropriated of the term when they used it for a worldview that was not based on the Judeo-Christian religions. This feeling cannot be justified unless we refuse to recognize its earlier use within a non-Christian philosophy by the Neo-Platonists. As a matter of fact, HPB did claim the Society was a successor of what Prof. Wilder called the “Theosophical Eclectic School” of Neo-Platonism:
The chief aim of the Founders of the Eclectic Theosophical School was one of the three objects of its modern successor, the Theosophical Society, namely, to reconcile all religions, sects and nations under a common system of ethics, based on eternal verities. 
The most important of [the Society’s objects] is to revive the work of [the Neo-Platonist] Ammonius Saccas, and make various nations remember that they are the children “of one mother.” 
Since we can argue that modern Theosophy is closer to the original Neo-Platonic system than Christian theosophy is, Mme. Blavatsky seems justified in having used the term for her teachings.
This being said, we have to keep in mind that HPB was not so much concerned with the “academic” aspect of a word that has been used with a multiplicity of meanings. Just as the term “gnosis” can be used in a universal way, with no reference to a particular school of philosophy or religion, she employed the term “Theosophy” more based on its meaning than on the traditions that had previously used it:
The Theosophical Society, then, does not derive its name from the Greek word Theosophia, composed of the two words “God” and “wisdom” taken in the dead letter, but rather in the spiritual sense of the term. It is the Society for searching into Divine Wisdom, occult or spiritual wisdom. 
Common elements in the various theosophies
One feature that strikes us when reading the teachings of those “possessed of divine wisdom” is that there is no doctrinal unity among them. Jacob Brucker (1696-1770), one of the first historians of Western philosophy, wrote about Christian theosophy: “There are as many theosophical systems as there are theosophers.”  This statement is applicable to other theosophies as well. There is a marked difference between the approaches of Plotinus and Iamblichus, while some people call “Neo-Theosophy” the teachings of Annie Besant and C. W. Leadbeater because they differ in some aspects from those of H. P. Blavatsky.
If this is the case within the particular traditions, what happens when we compare different theosophies, with differences in language and in their religious or philosophical background? Do they share any common elements?
Jacob Brucker identified some doctrines present in all of the Christian theosophical teachings. These principles, when expressed in a more religious-neutral language, are also to be found in Neo-Platonism and in modern Theosophy. They include the idea that everything emanates from a common source and must return to it; that one can get an immediate revelation of the soul by divine means or faculties, and not by philosophical reason; that the universal spirit resides in all things and we can find “signatures” of the divine everywhere; that the forces of nature can be manipulated by magical means; and that human beings are three-fold, being composed of a divine spark, an intermediary spirit or soul, and a physical body.
But perhaps what theosophoi, theosophers, and Theosophists have in common cannot be found so much at the doctrinal level, but rather at the level of attitudes of mind and general notions. For example, modern scholar Antoine Faivre (again in relation to the Christian theosophy, but applicable to the Neoplatonic and the modern ones) describes three common notions found in most theosophical systems: The interest in the relationship between Man, God and the Universe; the use of myths to explain reality; and the possibility of direct access to higher worlds.  Working on this line of thought, we can add some other common features:
i) The lack of doctrinal uniformity. This fact discussed earlier is not merely a negative quality but an important common feature of all theosophical teachers. Given the fact that their knowledge is not the result of reading and reasoning, but of a supra-conceptual wisdom, those in touch with it have to find their own words in an attempt to describe their original spiritual perceptions. Since the spiritual realities cannot be appropriately expressed through words created to describe the material world, their teachings will be different, and even seem to be opposing in many points, without necessarily being really so. This is also a reason why many of them chose the fluid language of symbols and allegories to transmit their wisdom.
ii) Knowing by personal experience about the limitations of language to describe spiritual realities, they are not literalists, and usually advocate for an esoteric understanding of sacred scriptures and myths.
iii) Theosophical authors tend to be eclectic, being inclined to integrate different elements (even from other traditions) within a general, harmonious whole. Theosophy is essentially holistic, frequently aiming at offering “a synthesis of Religion, Philosophy and Science,” as described in the subtitle of Blavatsky’s Secret Doctrine.
iv) Those in touch with theosophia seek union with the divine, becoming at the same time spectators of the “mysteries of creation”. These new perceptions and images are not created by the activity of the intellect, but by divine revelations. Therefore, theosophical teachings are not only mystical, but also metaphysical, including a cosmology, a theogony, and an anthropogenesis.[****] Due to the rich intellectual aspect of the theosophical teachings there is the danger of forgetting the real purpose of its metaphysics. It is not meant to satisfy the intellectual curiosity of the student. In the theosophical view, human beings (microcosm) are an expression and reflection of the universe (macrocosm), containing in them every element present in the cosmos. By knowing the universe we get to know our true nature and potentiality, as well as our relation to the whole. This knowledge becomes thus an important element of the theosophical spiritual practice.
v) All theosophies encourage an inner path, which is to be treaded individually. The “battle” between the spiritual and the material takes place inwardly, and produces the soul’s transmutation and a spiritual awakening. Man does not find God or the Divine in a temple but in his heart. However, although this intimate experience is independent of any external framework, many of those “wise in things divine” have created spiritual societies, orders, or communities to encourage and assist people in this individual change. These organizations were neither lay nor clerical. They were composed of people who maintained their outward place in society, but who were inwardly devoted to the spiritual practice. They existed in the boundaries between institutional religions and the lay populace. 
vi) The direction of this inner path is from the bodily consciousness towards an illumined, spiritual one. In other words, the psychological ego and its desires must be transcended. Here lies an important difference with the New Age. Although this movement shares many doctrinal elements with theosophy, its approach is typically the opposite one, focusing on the personal ego, and regarding the universal laws as means to produce personal satisfaction, which is mistakenly taken as a “spiritual state.”
The Theosophist, November 2011
NOTES[*] Porphyry also wrote about foreign sages (Egyptian and Indian) as being theosophoi (De Abstinentia, IV.9 and 17), while Iamblichus applied the term to the Indian yogis or sadhu-s. (De Mysteriis 7.1) [**] Among the Greeks theosophia was generally regarded to be higher than theologia, since the source of the former is a direct perception or experience of the divine, while theologia is based on reasoning about the divine. [***] The mystics mentioned by HPB in this quote lived from the 1200s to the late 1600s. Though not theosophers, a number of them are regarded as early influences in the shaping of Christian theosophy. [****] This is an important difference with the mystics of the Catholic type, who are usually not interested in the workings of the universe but simply aim at going beyond all images to reach a state of union with God.