Book 27 The Art of Synthesis

by Alan Leo

Chapter VI Mercury, The Thinker

Contents List:

God's Messenger
Mercury and Saturn
Mercury and Memory
Mercury and Mars
Mercury and Venus
Mercury and Knowledge
The Caduceus
Mercury in Combination
Mercury and The Nervous System
Mercury in the Horoscope

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Towards New Knowledge
Information and Technology, Part 2

God's Messenger

Mercury, 'the winged Messenger of the Gods', is the expressor, the mirror, of all the planets. All who study Astrology for any length of time sooner or later become aware of the fact that the planet which represents the conscious human being more directly than any other, and which most effectually acts as an agent or interpreter of the influence of other planets, is Mercury.

It is truly said that each planet plays its part in forming and influencing the mind, but it is the planet Mercury which governs the abstract mind, or the mind in its totality. Probably the best definition of Mercury's vibration would be that it was lord over the rational mind or mental body, and in that respect signified the memory of each individual. [The individual or permanent memory is meant here, not the pesonal, which is governed by the Moon. AL] It is distinctly the 'spiritually human' portion of the Ego, the Messenger of the Gods to man, whose wings carry him from Earth to heaven. If we think of man as possessing a soul having three phases, or aspects, i.e., animal, human, and spiritual, Mercury will represent that phase which is neither animal nor spiritual, but distinctively spiritual-human.

Apart from all considerations of good, bad, or indifferent, Mercury connected with Saturn causes the mind to become crystallised, solid, concrete, and material, thus rendering it matter-of-fact and practical, or grave and studious. Allied with Jupiter, it becomes more expansive and philosophical, inclining the mind to reflection, either moral, ethical, or religious in its nature. In the same manner, if allied to Venus, the mind is artistic, cheerful, and refined, while if connected with Mars, energetic, smart, self-assertive, and impulsive.

It would seem that whatever planet Mercury is joined to by aspect is interpreted in its true character by conforming the mind to its own nature; and for this reason it is said that Mercury is a 'convertible' planet, being affected according as it is aspected by, or placed in relation to any other planet. It is in Mercury that sex distinctions are usually lost, for on the plane of pure mind sex disappears.

When Mercury is freed from all contact with other planets and the Ego is able to use its influence without being led captive thereby, Mercury represents The Thinker.

Meditation upon the 'Caduceus', which forms the true symbol of Mercury, will reveal many of the mysteries connected with this planet. The two serpents twisted round the rod denote the 'life' and 'form' sides of the Ego's expression, the rod in the centre symbolising the one eternal changeless Self.

A considerable portion of the correct judgment of a nativity is derived from a study of Mercury, its position, aspects, and progress, the tendency of the mind being easily seen from the sign which Mercury occupies at birth.

Thoughts are things. As Mercury forms the mind by acting as a mirror of all images to be reflected, so the Ego is absorbed by, or identifies itself with the form, taking the image unto itself, so to speak. But, of itself, Mercury is only the representation of that which thinks, and so for the time of the one Earth-life, Mercury is The Thinker, transforming the essence of all thought into memory.

Mercury is therefore God's instrument, the word of God, or a ray of the Sun. By thought, speech, and action, it either builds forms or breaks and dissolves them, for it is the power of the three in one. In conjunction with each planet, Mercury has a special mission to perform; also when in any aspect to any planet.

Mercury and Saturn

If connected in any manner with the planet Saturn, Mercury makes all things corporeal, substantial, and practical, inclining those born under this influence to science and all work requiring concentrated thought and careful analysis. It is the most tangible and permanent vibration that Mercury can express, but it acts according to the nature of the aspect.

The Conjunction is the most potent. In this case thought and action become one, whether for good or ill, displaying concentration and much power of continuity but modified in its expression by the sign through which it is manifesting.

The Adverse Aspects cause grave anxiety, worry, and a constant disturbance of the mind, which is gradually consolidated by sorrow, grief, and continuous limitations of action which cause the mind to ponder over the restrictions and obstacles it meets.

The Benefic Aspects refine and chasten the mind through harmonious thought and action, causing a philosophical attitude which tends to depth and sincerity, faithfulness and truth.

The Opposition is as powerful as the Conjunction, but thought becomes liberated by disappointments, failures, and errors of judgment caused by fear, lack of initiative, and procrastination.

Mercury and Memory

As analogous to quicksilver, largely used for extracting gold (the Sun) from its ores, the planet Mercury opens up a wide field of new thought in connection with its influence in every nativity.

A simple laboratory experiment will very well convey its nature as illustrating at once its powers of perception and reflection, and also its function of memory, both personal and individual.

If a little quicksilver (mercury, Hg) be rubbed in a mortar or basin with a little powdered chalk, it will soon be found to run into small globules which will not again coalesce. This process can be carried on until the globules are so finely divided and intimately mixed with the chalk as to present a smooth blue-grey appearance, being apparently one uniform substance in a powdery form. In this state it corresponds to the separated memories of countless Earth-lives or incarnations, the chalk symbolising the material conditions of those lives.

If now a little dilute nitric acid be added to the powder, there will be a brisk effervescence, and after the reaction has subsided the chalk will be found to have vanished while the quicksilver is found again as one bright shining globule at the bottom of the basin.

This corresponds to the synthesised memory of many lives which is one day attained, and which constitutes experience, being represented in the horoscope by Jupiter Wisdom.

Suppose the chalk in the experiment had contained many particles of various metals gold, tin, silver, copper, etc., it can easily be seen that only those tiny globules which came into contact with them could amalgamate therewith: but since all of these particles are capable of being absorbed by mercury, then, on the solution of the chalk by the acid (typifying the dissolution of the material universe) the remaining globule of mercury would contain the whole of the various metals (experience) extracted. By distilling off the mercury, these could be regained as a pure alloy (transcendental wisdom).

Little wonder, then, that Nebo or Mercury was worshipped as the greatest of all the lesser gods, being the divine Messenger of the Sun, chief of all Gods, the God of the Solar System (and also ruler over all lesser systems).

Mercury and Mars

When Mercury is influenced by Mars, the separative principle is the stronger and the mind has no adhesiveness or attachment; for the fire of Mars burns in the mind and makes it a tormenting fire in which desire is ever leading it captive, a slave to passion and anger. For Mars is 'the wrath of God', the separative and destroying element, the counterfeit of the Spirit, and must either be transmuted into Venus or destroyed by dissipation. Mars is the elemental of the astral plane, the Hell in which the mind is consumed until all dross is burnt out and the soul or 'Manas' is set free to fly heavenward.

Mercury and Venus

In conjunction with Venus, Mercury shows the heaven-born mind: the artistic, refined, and pure love desire. This is the only aspect or position of Mercury which leaves it absolutely free to rise into the heaven world the Deva-kingdom, the land of the Shining Ones.

Mercury is the Christ between the two thieves on the cross, Saturn and Mars, only one of which can enter into Paradise with his lord. Mercury is the principal planet to study in every nativity: for it is the ruler of the abstract mind, the highest part of human existence during its pilgrimage through the 'circle of twelve'. It is that which in conjuntion with Saturn incarnates afresh at every new birth, retaining the cream of memory as a memento of each Earth-life; and therefore no time or labour can be considered wasted that is spent in the study of all that this planet denotes in each nativity.

Mercury and Knowledge

In its highest expression, Mercury is the planet of the adept, the man for whom Earth lives are numbered and who is within measurable distance of final release from physical matter. In the youngest as well as in the oldest ego, it denotes the powers of adaptability possessed. The adept can adapt himself to all environments and to every phase of existence, and in this fact lies the secret as to the growth of every ego and its stage in evolution. Some can adapt themselves only to physical environments, though these may be of all grades from coarse to fine. Others can extend beyond this to emotional conditions of all kinds. But only a few at our present stage of evolution can adapt themselves to mental states of consciousness, enabling them to understand every type of mind and to respond to all the numerous and various mental vibrations which come from the Manasic Plane. These are the souls who are preparing to become adepts by controlling their minds, realising that the mind is only an instrument for the soul's use; or, in other words, that Mercury is but the Word of God, which is to be made manifest in the flesh the divine Mesenger, the Prometheus, who stole the fire from heaven that it might become a living flame on Earth.

If a clue is wanted to the essential nature of the planet Mercury regarded from a psychological standpoint, it is apparently supplied by the word Knowledge. It is therefore necessary that there shall be a clear understanding of what this word means; of the mode of operation of the mind when 'knowing' anything; and of how the knowledge aspect of consciousness is evolved.

It must be borne in mind that this word is used here in a broad and comprehensive sense, as covering all operations of the mind that are included under such terms as 'reason', 'intelligence', 'understanding', 'intellect', 'wisdom'.

The simplest act of consciousness in any entity is inward response to a stimulus from without. This may be regarded as the fundamental unit of consciousness, and out of it all mental processes whatever are built or evolved. In itself, it is neither intellect, feeling, nor will, although it carries all three as potential within it. There is the passage of the shock from the surface to the centre; the response at the centre; and the passage outward of a wave or vibration reversing the first. The unit of consciousness is one, but these three elements are inevitably implied in it, although not separated as such in consciousness.

When accompanied by a sense either of pleasure or pain, no matter in how rudimentary a degree, it forms the germ of what in man become feelings, emotions, passions, etc. The consciousness registers each of these feelings, and their reproduction from within in the absence of the exciting stimulus from without constitutes memory.

When the entity is so far evolved as to be capable of noting a relation between any two acts of consciousness, whether simultaneous or successive, the foundation is laid for what in man becomes intellect, knowledge, understanding, etc. This consciousness of relation may, of course, also be reproduced from within as memory.

A creature eats a piece of food, and experiences pleasure in doing so; this is consciousness as feeling or sensation. The memory of this pleasure causes a craving for its repetition; which is desire. After a sufficient number of repetitions, the creature arrives at the stage of knowing that a certain object gives pleasure when tasted. If we suppose that the object is recognised by the sense of sight, this act of 'knowing' means that a relation has been established between two distinct acts of consciousness, which in this case are seeing and tasting; and that the relation is so definitely fixed that when the act of seeing takes place the memory of past pleasures in tasting is immediately revived. The knowledge consists not in the sight alone nor in the taste alone but in the bringing of the two into relation with each other in consciousness; in the recognition of the fact that the thing seen is followed by an agreeable taste.

A concrete object is 'known' when the evidence supplied to the consciousness by the various senses is held together as one whole in the mind, so that the presentation of one portion recalls the rest; as when the smell of an orange suggests its shape, colour, and taste to one who has previously seen and eaten oranges.

The degree of knowledge obviously varies with the amount of previous experience that has been stored in the mind. For instance, when an astronomer 'knows' a star, his consciousness reproduces a highly complex group of past experiences. A child may also 'know' a star when he sees one, but this knowledge implies the reproduction of a very much smaller group. The difference, however, is only one of degree and not of kind.

Abstract knowledge implies that an enormous number of units of consciousness have been united into one whole, consisting first of small groups and then groups of groups, and that these groups are contemplated in the mind apart from the separate acts of consciousness out of which they were originally built. For instance, the law that 'the radius vector of a planet revolving round the Sun sweeps out equal areas in equal times' implies the presence in the mind of such ideas as velocity, momentum, mass, area, etc.; each one of these in its turn was built of a number of smaller groups; and the whole could, at least theoretically, be resolved into a vast number of separate units of consciousness.

All human knowledge, concrete or abstract, is built up in this way and the action of the mind in so building it may apparently be divided into three stages: Perception, Discrimination, and Unification.

The second of these three seems to be more particularly the region of Mercury. This planet can associate itself with any influence, whether mental, emotional, or practical; but if an effort is made to define its characteristics when alone and not combined with any other heavenly body, this is apparently the class into which it falls. Thought, knowledge, undertanding, discrimination, are its mode of operation. To use technical terms, it belongs to the Buddhic or pure reason sub-division of Manas; or at least this is its highest function in the humanity of today, although it would seem to follow of necessity that an even higher mode will exist when the purely intellectual stage of evolution has been passed.

To speculate about that higher mode is difficult; but if we assume that the mind in its evolution is first stored with facts of the outer world or experience, and afterwards with all-embracing laws founded on these facts in all departments of being, a time will come when the outward presentation of any fact is immediately answered, fully and completely, by the inward response of the soul. The outer appeal and the inner reply are identical, and the result is perfect sympathy, absolute harmony, infallible wisdom.

When this high level of evolution has been attained, knowledge and love have become one, and are no longer separated or contradictory as at present. Knowledge or Mercury, and love or Venus, both alike imply duality. There can be no knowledge without the existence of both Knower and Known; there can be no love without the existence of both lover and loved. When the two become one, nothing remains that we can regognise as either knowledge or love. Both these have their origin when unity produces duality-in-unity, symbolised by the conjunction of Mercury and Venus. In the language of mysticism, the Absolute gives birth to Father-Mother, the two-in-one; knowledge, symbolised by man, and love, symbolised by woman, diverging from a common root.


If a search is made through the literature of mysticism, it will be found that among practically all schools, Mercury, Hermes, Buddha, whatever name is used, stand for the adept. Why is this? Because this is the planet and god of knowledge in the fullest and highest sense of the word.

By way of illustration, consider the ordinary man of today. When not too sceptical, he believes in a life after death but has, at any rate for the most part, to take it on trust; he cannot prove it. In what respect does the adept differ from him? In that he knows. He is as fully and completely acquainted with the life after death as he is with that of this world. He has visited and explored both, and holds the facts of both in his memory not as the result of hearsay or of book-learning, but of personal experience and knowledge. The one believes, the other knows. This is the gift of Mercury.

The Caduceus

The symbol both of the god and of the planet is the Caduceus, a winged rod round which two serpents are twined in such a way as to present nodes and internodes. This has a very profound significance which, however, varies according to the method of application. It represents the spirally-moving creative energy both in man and in the Universe. Cosmically, this takes its origin when primal unity is differentiated into duality, positive and negative, with a current of energy flowing between them; and, as has been shown, it is just this state of inter-related duality that is signified by Mercury.

The same energy is said to be aroused in man in the course of evolution and also by occult training. It is represented as being practically all-powerful and therefore extremely dangerous in the hands of the unfit.

Herbert Spencer has shown that all motion is rhythmical, and Sir William Crookes has proved that the evolution of the chemical elements from one primordial substance can be accounted for by a spiral movement of condensation round a central axis: exactly that which is represented graphically by the Caduceus.

Hindu mystic literature contains frequent references to two currents, positive and negative, of vital force in the human body, represented as circulating on each side of a central and neutral third connected with the spinal cord, controlling the vitality of the whole body, and themselves capable of control by the mind.

Mercury in Combination

In the horoscope, Mercury stands for intelligence in all shades and degrees of development, from the merest superficiality up to the sublimest genius. It also represents the influence of the mind upon the body in health and disease; and its position and aspects can often be shown to influence disease.

It has to do with all circumstances relating to the acquisition and diffusion of knowledge, in small things as well as in great. Its duality and relationing are shown in its rulership over those matters classed under the third house and Gemini. Inasmuch as it represents that intelligence without which human co-operation and civilised life are impossible, there is scarcely a business, occupation, or profession, high or low, in which it is not a factor of more or less importance.

Probably the most unique characteristic of Mercury is its power of combining with the other planets and taking upon itself many of their qualities while at the same time not losing its own. In aspect to the Sun it will gain in comprehensiveness and dignity; to the Moon, fertility and intuition; to Venus, social and emotional qualities; to Mars, energy, ardour, and a lively wit; to Jupiter, soundness of judgment and breadth of human sympathy; to Saturn, depth, sobriety, and will; to Uranus, intensification of intellectual power and activity, with inclination to matters characteristic of that planet; and to Neptune, receptivity and adaptivity to matters of feeling.

This power of combination is of course thoroughly characteristic of intellect, which is represented by Mercury. As previously shown, its lowliest and most primitive form is the combination of two simple acts of consciousness, the bringing of them into relation with one another and comparing them.

The evolution of intellect in its further stages consists in acquiring greater power of combination between separate mental acts, greater storage of mental experiences, and the ability, either by deliberate or instinctive memory, to reproduce any combination the moment it is required. To do this, the mind has to be stored with the results of doings and feelings as well as with abstract thinking. It must have observed feelings, sensations, emotions, passions, the causes that gave rise to them, and the results, favourable or adverse, which ensued; and must have within itself soundness of judgment to separate the beneficial and desirable from those which are the reverse. In short, the mind holds the balance between feelings and acts, and must be able to combine with and respond to all varieties of these.

Mercury and The Nervous System

The simplest classification of the nervous system is into sensory nerves, brain, and motor nerves. The sensory nerves, which convey sensations to the mind, correspond to Cardinal signs and their associated planets. The motor nerves, which convey acts of will outward, resulting in contractions of muscles and movements of organs, correspond to the Fixed signs and associated planets, while The Mind at the centre holds the balance between the two, co-ordinates the two, is in touch with both, corresponding to Mutable signs. This is the oriental division into Gnyanendriyas, or centres for receiving sensation; Karmendriyas, or organs of action; and the balancing intelligence at the centre within.

If these are brought into relation with the three divisions or stages of mental action given above, we have the following suggested table of correspondences:

Sensory NervesBrainMotor Nerves
Rajasic ManasSattvic ManasTamasic Manas
Manas or Buddhi or Atma or
Creative MindPure ReasonAbstract Spirit

The power of combination shown by the planet has a parallel in the metal associated with it alchemically; for mercury or quicksilver unites with other metals to form a series of combinations called amalgams which are quite characteristic of it. An illustration of this has already been given. [See Mercury and Memory]

Mercury in the Horoscope

In its application to the horoscope, and as representing intelligence, Mercury varies its influences according to the planetary ruler of the sign in which it is situated, in this respect resembling the two luminaries. Its nature is active and changeable. It governs the brain and nervous system in common with the Moon; and through the nerves it influences that part of the body signified by the sign in which it is placed and the planetary ruler thereof. It relates to the tongue and the hands as agents for the expression of the mind.

Among those following occupations ruled by Mercury may be mentioned speakers and writers of all kinds, such as lawyers, preachers, public speakers, clerks, accountants, authors; students and teachers of all degrees, high and low; those engaged in the diffusion of knowledge, such as reporters, editors, telegraphists, secretaries, messengers, travellers, booksellers.

When angular, especially if in the first, seventh, or tenth houses, it gives ability for public speaking. In reality it has a bearing upon such a great variety of occupations and pursuits that it can never be taken alone but always in conjunction with the sign in which it is placed and the planet with which it is in closest aspect. Mercury is subordinate to the Sun, just as the mind is an instrument of the will; and unless otherwise indicated, it seldom signifies superiors, authorities, heads, those who are supreme; but generally a person who, however many he may have under him, is himself controlled, at least nominally, by a superior or partner.

When rising, it indicates an active mind and often an active body too. The intelligence is well developed and the mental ability good. There is the capacity to receive an education to almost any extent should circumstances be favourable. When angular, there is often considerable ability for languages. The native is inventive, ingenious, argumentative, of lively wit, learning things easily, imaginative, fond of novelty, and changeable.

It is generally known that there are many types of mind. Just as the sign-position of the Moon is a clue to the particular type of feelings and emotions innate in each personality, so that of Mercury indicates the type of intelligence, intellect, reason. In each case the type is inborn, and shows out more or less clearly throughout the whole of life from the earliest years to the latest. Education, training, the influences of family life, of business, and of the world, may each and all have much effect in refining or coarsening, widening or narrowing, the mind; for within each class there are many grades, high and low; but the type itself does not alter. For instance, if the innate quality of the mind is represented by, say, a combination of Mercury with Saturn, this will give the general colouring for the whole of the life. No training, no effect of the will, no amount of experience, no 'conversion', will change one type into another. All that these can do is to effect modifications, to produce sub-types, by bringing the influence, good or bad, of other planets to bear upon that which is indicated by the radical combination. Careful observation and experience will fully corroborate this statement.

It is not always easy to separate the type of intellect from that of the feelings. In some persons one of these may be very much stronger than the other, the intellect than the feelings or vice versa; and then the stronger so overpowers the weaker as to render difficult the task of identifying it. Actions springing from the one are attributed to the other, and the basic lines of character are misunderstood. Again, in some directions the two may blend very closely; and in art, music, poetry, drama, some kinds of authorship, oratory, etc., feeling and intellect are almost equally essential if success is to be attained.

As previously stated, Mercury can and does combine with any of the planets; but for purposes of classification it is best to follow the type indicated by the ruler of the sign in which Mercury is placed at birth according to the ancient scheme of signs handed down by Ptolemy. This gives what may be called the basic type, but as a matter of course it is seldom found alone. The planet with which Mercury is in closest and strongest aspect at birth is very important, and in some cases this influence may become as strong as that of the lord of the sign. For instance, if Mercury is in conjunction with Venus in Capricorn, the Saturnian influence of the sign will give gravity and thoughtfulness, while Venus will impart those social instincts that are often foreign to Saturn.

There are obviously many varieties of each type, superficial and profound, and many combinations; and each may vary somewhat according to the degree of education and refinement of the native. The good or bad luck attending each is a matter for separate consideration under the head of aspects.