Giordano Bruno's Definition of Magic

On Magic

First, the term ‘magician’ means a wise man; for example, the Trismegistes
among the Egyptians, the druids among the Gauls, the gymnosophists
among the Indians, the cabalists among the Hebrews, the magi among the
Persians (who were followers of Zoroaster), the sophists among the Greeks
and the wise men among the Latins.

Second, ‘magician’ refers to someone who does wondrous things merely
by manipulating active and passive powers, as occurs in chemistry, medicine
and such fields; this is commonly called ‘natural magic’.

Third, magic involves circumstances such that the actions of nature or
of a higher intelligence occur in such a way as to excite wonderment by
their appearances; this type of magic is called ‘prestidigitation’.

Fourth, magic refers to what happens as a result of the powers of attraction
and repulsion between things, for example, the pushes, motions and
attractions due to magnets and such things, when all these actions are due
not to active and passive qualities but rather to the spirit or soul existing in
things. This is called ‘natural magic’ in the proper sense.

The fifth meaning includes, in addition to these powers, the use of
words, chants, calculations of numbers and times, images, figures, symbols,
characters, or letters. This is a form of magic which is intermediate between
the natural and the preternatural or the supernatural, and is properly called
‘mathematical magic’, or even more accurately ‘occult philosophy’.

The sixth sense adds to this the exhortation or invocation of the intelligences
and external or higher forces by means of prayers, dedications,
incensings, sacrifices, resolutions and ceremonies directed to the gods,
demons and heroes. Sometimes, this is done for the purpose of contacting
a spirit itself to become its vessel and instrument in order to appear wise,
although this wisdom can be easily removed, together with the spirit, by
means of a drug. This is the magic of the hopeless, who become the vessels
of evil demons, which they seek through their notorious art. On the other
hand, this is sometimes done to command and control lower demons with
the authority of higher demonic spirits, by honouring and entreating the
latter while restricting the former with oaths and petitions. This is
transnatural or metaphysical magic and is properly called ‘theurgy’.

Seventh, magic is the petition or invocation, not of the demons and
heroes themselves, but through them, to call upon the souls of dead
humans, in order to predict and know absent and future events, by taking
their cadavers or parts thereof to some oracle. This type of magic, both in
its subject matter and in its purpose, is called ‘necromancy’. If the body is
not present, but the oracle is beseeched by invoking the spirit residing in
its viscera with very active incantations, then this type of magic is properly
called ‘Pythian’, for, if I may say so, this was the usual meaning of ‘inspired’
at the temple of the Pythian Apollo.

Eighth, sometimes incantations are associated with a person’s physical
parts in any sense; garments, excrement, remnants, footprints and anything
which is believed to have made some contact with the person. In that case,
and if they are used to untie, fasten, or weaken, then this constitutes the
type of magic called ‘wicked’, if it leads to evil. If it leads to good, it is to be
counted among the medicines belonging to a certain method and type of
medical practice. If it leads to final destruction and death, then it is called
‘poisonous magic’.

Ninth, all those who are able, for any reason, to predict distant and
future events are said to be magicians. These are generally called ‘diviners’
because of their purpose. The primary groups of such magicians use either
the four material principles, fire, air, water and earth, and they are thus
called ‘pyromancers’, ‘hydromancers’, and ‘geomancers’, or they use the
three objects of knowledge, the natural, mathematical and divine. There
are also various other types of prophecy. For augerers, soothsayers and
other such people make predictions from an inspection of natural or physical
things. Geomancers make predictions in their own way by inspecting
mathematical objects like numbers, letters and certain lines and figures,
and also from the appearance, light and location of the planets and similar
objects. Still others make predictions by using divine things, like sacred
names, coincidental locations, brief calculations and persevering circumstances.
In our day, these latter people are not called magicians, since, for
us, the word ‘magic’ sounds bad and has an unworthy connotation. So this
is not called magic but ‘prophecy’.

Finally, ‘magic’ and ‘magician’ have a pejorative connotation which has
not been included or examined in the above meanings. In this sense, a
magician is any foolish evil-doer who is endowed with the power of helping
or harming someone by means of a communication with, or even a pact
with, a foul devil. This meaning does not apply to wise men, or indeed to
authors, although some of them have adopted the name ‘hooded magicians’,
for example, the authors of the book De malleo maleficarum (The
Witches’ Hammer). As a result, the name is used today by all writers of this
type, as can be seen in the comments and beliefs of ignorant and foolish
priests.

Therefore, when the word ‘magic’ is used, it should either be taken in
one of the senses distinguished above, or, if it is used without qualifications,
it should be taken in its strongest and most worthy sense as dictated by the
logicians, and especially by Aristotle in Book v of the Topics. So as it is used
by and among philosophers, ‘magician’ then means a wise man who has the
power to act. Nevertheless, the fact remains that the word, when unqualified,
means whatever is signified by common usage. Another common
meaning is found among various groups of priests who frequently speculate
about that foul demon called the devil. Still other meanings are to be
found in the common usages of different peoples and believers.
Given these distinctions, we will deal generally with three types of
magic: the divine, the physical and the mathematical. The first two of these
types of magic necessarily relate to what is good and best. But the third type
includes both good and evil, since the magician may direct it towards either.
Although all three types agree on many principles and actions, in the third
type, wickedness, idolatry, lawlessness and charges of idolatry are found
when error and deception are used to turn things which are intrinsically
good into evil. Here, the mathematical type of magic is not defined by the
usually mentioned fields of mathematics, i. e., geometry, arithmetic, astronomy,
optics, music, etc., but rather by its likeness and relationship to these
disciplines. It is similar to geometry in that it uses figures and symbols, to
music in its chants, to arithmetic in its numbers and manipulations, to
astronomy in its concerns for times and motions, and to optics in making
observations. In general, it is similar to mathematics as a whole, either
because it mediates between divine and natural actions, or because it shares
or lacks something of both. For some things are intermediates because they
participate in both extremes, others because they are excluded from both
extremes, in which case they should not be called intermediates but a third
species which is not between the other two but outside of them. From what
has been said, it is clear how divine and physical magic differ from the third
type.

To turn now to the particulars, magicians take it as axiomatic that, in all
the panorama before our eyes, God acts on the gods; the gods act on the
celestial or astral bodies, which are divine bodies; these act on the spirits
who reside in and control the stars, one of which is the earth; the spirits act
on the elements, the elements on the compounds, the compounds on the
senses; the senses on the soul, and the soul on the whole animal. This is the
descending scale.

By contrast, the ascending scale is from the animal through the soul to
the senses, through the senses to compounds, through compounds to the
elements, through these to spirits, through the spirits in the elements to
those in the stars, through these to the incorporeal gods who have an ethereal
substance or body, through them to the soul of the world or the spirit of the
universe; and through that to the contemplation of the one, most simple,
best, greatest, incorporeal, absolute and self-sufficient being.
Thus, there is a descent from God through the world to animals, and an
ascent from animals through the world to God. He is the highest point of
the scale, pure act and active power, the purest light. At the bottom of the
scale is matter, darkness and pure passive potency, which can become all
things from the bottom, just as He can make all things from the top.
Between the highest and lowest levels, there are intermediaries, the higher
of which have a greater share of light and action and active power, while the
lower levels have a greater share of darkness, potency and passive power.
As a result, all light in lower things, which comes to them from above, is
more powerful in higher things. And also, all darkness in higher things is
stronger in lower things. But the nature and power of light and darkness
are not equal. For light diffuses and penetrates through the lowest and
deepest darkness, but darkness does not touch the purest sphere of light.
Thus, light penetrates and conquers darkness and overflows to infinity,
while darkness does not penetrate or overwhelm or equal the light, but
rather is very weak compared to light.

text lifted from this excellent Philosophy of Magic Course Website