Between 1598 and 1604, Fludd studied medicine, chemistry and hermeticism on the European mainland. His itinerary is not known in detail. On his own account he spent a winter in the Pyrenees studying theurgy (the practice of rituals) with the Jesuits.
On his return to England, Fludd entered Christ Church, Oxford. In 1605 he graduated M.B. and M.D. He then moved to London, settling in Fenchurch Street, and making repeated attempts to enter the College of Physicians. Fludd encountered problems with the College examiners, both because of his unconcealed contempt for traditional medical authorities, and because of his attitude. After at least six failures, he was admitted in 1609. Subsequently both his career and his standing in the College took a turn very much for the better. He was on good terms with Sir William Paddy. Fludd was one of the first to support in print the theory of the circulation of the blood of the College's William Harvey. To what extent Fludd may have actually influenced Harvey is still debated, in the context that Harvey's discovery is hard to date precisely. The term "circulation" was certainly ambiguous at that time.
Fludd died in London.
Fludd's illustration of man the microcosm within the universal macrocosm
Fludd was not a member of the Rosicrucians, as often alleged, but he defended their thought. He produced a quick work, the Apologia Compendiaria, against the claims of Libavius that the Rosicrucians indulged in heresy, diabolical magic and sedition, made in his Analysis confessionis Fraternitatis de Rosea Cruce (Analysis of the Confession of the Rosy Cross) of 1615. Fludd returned to the subject at greater length, the following year.
Apologia Compendiaria, Fraternitatem de Rosea Cruce suspicionis … maculis aspersam, veritatis quasi Fluctibus abluens, &c., Leyden, 1616. Against Libavius.
Tractatus Apologeticus integritatem Societatis de Rosea Cruce defendens, &c., Leyden, 1617.
Tractatus Theologo-philosophicus, &c., Oppenheim, 1617. The date is given in a chronogram. This treatise "a Rudolfo Otreb Britanno" (where Rudolf Otreb is an anagram of Robert Floud) is dedicated to the Rosicrucian Fraternity. It consists of three books, De Vita, De Morte, and De Resurrectione. In the third book Fludd contends that those filled with the spirit of Christ may rise before his second coming.
Johannes Kepler criticised Fludd's theory of cosmic harmony in an appendix to his Harmonice Mundi (1619).
Veritatis Proscenium Frankfort, 1621. Reply to Kepler. In it Fludd argued from a Platonist point of view; and he claims that the hermetic or "chemical" approach is deeper than the mathematical.
Monochordon Mundi Symphoniacum Frankfort, 1622. Reply to Kepler's Mathematice, 1622).
Anatomiæ Amphitheatrum, Frankfort, 1623. Includes reprint of the Monochordon.
Against the natural philosophers
Titlepage of the Summum Bonum under the name of Joachim Frizius
According to Brian Copenhaver, "Kepler accused Fludd of being a theosophist, and Kepler was right". Fludd was well-read in the tradition coming through Francesco Giorgi.Marin Mersenne attacked him in Quæstiones Celebres in Genesim (1623).
Sophiæ cum Moria Certamen, Frankfort, 1629. Reply to Mersenne.
Summum Bonum, Frankfort, 1629. Under the name Joachim Frizius, this was a further reply to Mersenne, who had accused Fludd of magic.
Fludd also wrote against The Tillage of Light (1623) of Patrick Scot; Scot like Mersenne found the large claims of hermetic alchemy to be objectionable. Fludd defended alchemy against the criticisms of Scot, who took it to be merely allegorical. This work, Truth's Golden Harrow, remained in manuscript.
The weapon-salve controversy
"Doctor Fludds Answer vnto M. Foster, or, The Sqvesing of Parson Fosters Sponge," &c., London, 1631, (defence of weapon-salve, against the Hoplocrisma-Spongus, 1631, of William Foster, of Hedgerley, Buckinghamshire); an edition in Latin, "Responsum ad Hoplocrisma-Spongum," &c., Gouda, 1638.
Cosmology and other works
'An Astrologer Casting a Horoscope' from Robert Fludd's Utriusque Cosmi Historia, 1617
Fludd's philosophy is presented in Utriusque Cosmi, Maioris scilicet et Minoris, metaphysica, physica, atque technica Historia (The metaphysical, physical, and technical history of the two worlds, namely the greater and the lesser, published in Germany between 1617 and 1621); according to Frances Yates, his memory system (which she describes in detail in The Art of Memory, pp. 321–341) may reflect the layout of Shakespeare's Globe Theatre (The Art of Memory, Chapter XVI).
In 1618, Fludd wrote De Musica Mundana (Mundane Music) which described his theories of music, including his mundane (also known as "divine" or "celestial") monochord.
Utriusque Cosmi … metaphysica, physica atque technica Historia, &c., Oppenheim and Frankfort, 1617–24. (It has two dedications, first to the Deity, secondly to James I, and copperplates; it was to have been in two volumes, the first containing two treatises, the second three; it was completed as far as the first section of the second treatise of the second volume.)
Philosophia Sacra et vere Christiana, &c., Frankfort, 1626; dedicated to John Williams.
Medicina Catholica, &c., Frankfort, 1629–31, in five parts; the plan included a second volume, not published.
Philosophia Moysaica, &c., Gouda, 1638; an edition in English, Mosaicall Philosophy, &c., London, 1659.
Religio Exculpata, &c. [Ratisbon], 1684 (Autore Alitophilo Religionis fluctibus dudum immerso, tandem … emerso; preface signed J. N. J.; assigned to Fludd).
Tractatus de Geomantia, &c. (four books), included in Fasciculus Geomanticus, &c., Verona, 1687.
An unpublished manuscript, copied by an amanuensis, and headed Declaratio breuis, &c., is in the Royal manuscripts, British Library, 12 C. ii. Fludd's Opera consist of his folios, not reprinted, but collected and arranged in six volumes in 1638; appended is a Clavis Philosophiæ et Alchimiæ Fluddanæ, Frankfort, 1633.
William T. Walker, reviewing two books on Fludd in The Sixteenth Century Journal (by Joscelyn Godwin, and William Huffman), writes that "Fludd relied on the Bible, the Cabbala, and the traditions of alchemy and astrology. Many of his contemporaries labelled Fludd a magician and condemned him for his sympathy for the occult." He cites Godwin's book as arguing that Fludd was part of the tradition of Christian esotericism that includes Origen and Meister Eckhart. He finds convincing the argument in Huffman's book that Fludd was not a Rosicrucian but was "a leading advocate of Renaissance Christian Neo-Platonism. Fludd's advocacy of an intellectual philosophy in decline has done much to assure his general neglect."
^Wolfgang Pauli, Wolfgang Pauli – Writings on physics and philosophy, translated by Robert Schlapp and edited by P. Enz and Karl von Meyenn (Springer Verlag, Berlin, 1994), Section 21, The influence of archetypical ideas on the scientific theories of Kepler. ISBN 3-540-56859-X, ISBN 978-3-540-56859-9.