Furthermore, this insistence on an astrological interpretation of cosmology directly influenced his other "scientific" works, something that is taken up in J. Peter Zetterberg's analysis of what he calls Dee's "hermetic geocentricity." After discussing the somewhat limited commentary on Copernicus' theory of heliocentrism present in Dee's strictly scientific works, Zetterberg suggests that "to resolve the general ambiguity that surrounds the question of Dee's cosmological views it is necessary to leave his works on practical science and turn instead to his occult interests." In Monas hieroglyphica, the only work in which Dee "reveal[s] a cosmology," Zetterberg identifies a kind of hidden meaning Dee proposes to exist in all earlier astronomical and astrological work. For Dee, understanding the functioning of cosmological bodies is less a strictly mathematical proposition and one that relies more on interpreting symbols, because:

"according to Dee, to understand the universe one need only decipher the signs of the heavenly bodies, for 'the common astronomical symbols of the planets (instead of being dead, dumb, or up to the present hour at least, quasi-barbaric signs) & #8230; [are really] characters imbued with immortal life and should now be able to express their special meanings most elegantly in any tongue and to any nation.'" (Zetterberg 389)

Dee constructs a glyph made out of a combination of symbols related to the classical planets, and in turn uses this glyph to argue for the geocentricity of the universe. It is not worth the time to point out the obviously flawed logic and process of argumentation Dee employs, any more than it would be worth debunking the claim that all matter is composed of one of four fundamental elements, or that personality is dictated by the balance of internal humours. Rather, this discussion of Dee's cosmology is relevant because it is precisely his work as a cosmologist and astrologer that gained him such favor from Queen Elizabeth and allowed him to gain an audience with Rudolph II.

John Dee's navigational and imperial works can be seen largely as a side effect of his alchemical investigations, as his astrological work is what so entranced Queen Elizabeth, and eventually Rudolph II (a keen alchemist himself.) Thus, both Dee's General and rare memorials pertaining to the Perfect Arte of Navigation and the more recently discovered "Brytanici Imperii Limites" can be read largely as works of royal flattery, to the point that "his cardinal references were based on the queen's body, using phrases such as 'on the left hand side of your majesty's throne,' 'under your crown,' and 'at the right side of your majesty.'" (MacMillan 154) in addition, Glyn Parry argues that "in the context of European politics, Elizabethan Court intrigues, and Dee's occult natural philosophy and magical imperialism," his navigational texts "reveal their covert purpose of recovering a lost British Empire...

As mentioned before, his belief in his own astrological system blinded him to the political (and scientific) realities that would be his unraveling.
In some ways, John Dee can be seen as the last gasp of the mystical in the face of a rapidly developing and enlightened planet. Despite his deserved lauding as a mathematician and scientist, it was his astrological, alchemical, and magical contributions which allowed him to rise to the post of favored adviser to Queen Elizabeth and fall to the point of his desperate defense in the face of imagined slights during the reign of King James. Furthermore, his magical thinking permeated even his navigational and imperial texts, so that although he is often credited as coining the term "British Empire," the empire of Dee's imagination was surely more fantastic, divine, and unknowable than any actual British conquests of the following centuries.

Bibliography

"A John Dee Chronology." Adam Matthew Publications. Available from http://www.ampltd.co.uk/digital_guides/ren_man_series1_prt1/chronology.aspx. Internet; accessed 20 March 2011.

Dee, John. General and rare memorials pertaining to the Perfect Arte of Navigation. 1575.

Dee, John. To the King's Most Excellent Majesty. 1604

Heppel, G. "Mathematical Worthies. II. John Dee." The Mathematical Gazette 5 (1895): 40.

MacMillan, Ken. "John Dee's "Brytanici Imperii Limites." "Huntington Library Quarterly 64 no. 1/2 (2001): 151-159.

Molland, a.G. "Review: Mathematical and Angelic Astronomy."The British Journal for the History of Science 13 no. 30 (1980): 255-258.

Parry, Glyn. "John Dee and the Elizabethan British Empire in Its European Context." The Historical Journal 49 no. 3 (2006): 643-675.

Rattansi, P.M. "Review: A Translation of John Dee's "Monas Hieroglyphica" (Antwerp, 1564), with an Introduction and Annotations." The British Journal for the History of Science 3 no. 1 (1966): 82.

Strathmann, Ernest a. "John Dee as Raleigh's "Conjurer." "Huntington Library Quarterly 10 no. 4 (1947): 365-372.

Zetterberg, J. Peter. "Hermetic Geocentricity: John Dee's Celestial Egg." Isis 70 no. 30 (1979): 385-393.