BornKent, England, circa1546
DiedLondon, England, 24 August 1595
Thomas Digges’s reputation among historians rests largely on the fact that he was the leader of the English Copernicans. Among astronomers, he is remembered as among the first to advocate an infinite stellar universe far outside the orbit of Saturn, populated by stars that might themselves have planets.
Thomas was the son of Leonard Digges and Bridget Wilford. He received his mathematical training from his father, who died while Thomas was in his early teens, and from John Dee , who described Thomas as his most worthy mathematical heir. Digges and his wife Agnes Saint Leger had six children, including Sir Dudley Digges and Leonard Digges the younger.
There is no record that Thomas attended any university; his proficiency in mathematical and military matters was derived from his father’s and Dee’s tutoring. He served the government in various capacities. Digges was one of the officers designated in 1582 to repair the harbor at Dover, on which he was engaged for several years; he also served as a member of Parliament in 1572 and 1584/1585 and as a general of the English forces in the Netherlands from 1586 to 1594. He was buried in the church of Saint Mary, Aldermanbury.
Thomas Digges added a discussion of the Platonic solids and five of the Archimedean solids to his father’s Pantometria(1571) and completed his father’s Stratioticos(1579). The second editions of both works provided answers to questions on ballistics that had been raised in the first edition of Stratioticos.
Digges’s reputation among his contemporaries rested on his observations of the new star of 1572, on his ability to cultivate mathematics, and on the preservation of his father’s writings and instruments. In Alae seu Scalae Mathematicae(1573), he published his observations of the star of 1572, which are regarded as the best published observations next to those of Tycho Brahe . Brahe’s high opinion of them is attested by his devotion of over 30 pages of his Progymnasmata(Prague, 1602) to Digges’s treatise.
Digges’s father is regarded as the maker of the first efficient telescopes, and Thomas was keen to enhance his father’s reputation as much as possible. Among the drawings and descriptions of instruments preserved by Digges are a drawing of a rectilinear scale with transversals and an illustration of the use of a theodolite for estimating the range of artillery rapidly and accurately. In the Stratioticos, he added a description of what appears to be a reflecting telescope – 35 years before Galileo Galilei and a full 100 years before Isaac Newton ’s reflecting telescope. Unfortunately, the instrument, if it was ever actually built, is no longer extant, and even the uses for it that Digges attributed to his father in the preface to Pantometriado not include any celestial observations.
Although Robert Recorde may have preceded him in urging careful consideration of the Copernican theory, already in the Alae(1573), Digges referred to the probable truth of the Copernican theory. In 1576, he added an English translation of parts of Book I of Nicolaus Copernicus ’s De revolutionibusto his father’s Prognostication everlastinge(1576). The full title is A Perfit Description of the Caelestiall Orbes according to the most aunciente doctrine of the Phythagoreans, latelye revived by Copernicus and by Geometricall Demonstrations approved. Digges contributed to a misunderstanding that referred to Copernicus as having revived Pythagorean doctrines, but he also altered the Copernican theory in a way that removed Copernicus’s ambiguity about the size of the universe. Copernicus imagined a finite universe with the stars located in the last sphere and the Sun at the center, but because of Copernicus’s uncertainty about the nature of space beyond the stars, he left the question whether it is finite or infinite to natural philosophers. It was Digges who first represented the stars in the Copernican system at various distances, thus committing the theory to an infinite space. By proposing that the stars are at varying distances, however, he was also trying to spur astronomers into making more observations in the hope that they would prove the Copernican theory true or in need of modification (Easton, 97b). However, he still retained the Sun at the center, indicating that he did not go as far as Giordano Bruno in his conception of an infinite universe. The English thus owe their understanding of the Copernican universe as infinite to Digges, who let his own interpretation pass as part of Copernicus’s own theory.
The fact that Digges did not carry out telescopic observations may be explained by the circumstances of his career and the fact that he never had the funds to carry out a systematic program of research. On the other hand, he may also have realized that with the instruments available, stellar parallax could still not be observed and so did not serve as a crucial experiment of the heliocentric theory. Digges suggested further that the decline in brilliance of the new star of 1572 might be the result of the Earth’s motion in its orbit away from the star. If that were true, then after it reached its maximum elongation, the star would begin to increase in brilliance, thus confirming the Earth’s orbital motion. In fact, the star continued to fade from view. The hope that a large collection of new and more accurate observations would quickly verify or correct the Copernican theory was too optimistic.
- Cooper, Thompson (1921–1922). “Digges, Thomas.” In Dictionary of National Biography, edited by Sir Leslie Stephen and Sir Sidney Lee. Vol. 5, pp. 976–978. London: Oxford University Press. (The article is inaccurate about Thomas’s early years because of a confusion with another Thomas Digges who matriculated at Cambridge University in 1546. It is a useful source for his nonmathematical publications and reports in MS.)Google Scholar
- De Morgan, Augustus. (1839). “Motion of the Earth.” The Penny Cyclopedia15: 454–458Google Scholar
- Digges, Thomas (1571). “A Mathematical Discourse of Geometrical Solids.” In Pantometria, byLeonard Digges. London: Henrie Bynneman.Google Scholar
- — (1573). Alae seu scalae mathematicae. London: Thomas Marsh.Google Scholar
- — (1576). “A Perfit Description of the Caelestiall Orbes.” In A Prognostication Everlastinge, by Leonard Digges. London: Thomas Marsh.Google Scholar
- — (1579). Stratioticos. London: Henrie BynnemanGoogle Scholar
- Easton, Joy B. (1971). “Digges, Thomas.” In Dictionary of Scientific Biography, edited by Charles Coulston Gillispie. Vol. 4, pp. 97–98. New York: Charles Scriber’s Sons.Google Scholar
- Granada, Miguel A. (1997). “Thomas Digges, Giordano Bruno e il Copernicanesimo in Inghilterra.” In Giordano Bruno, 1583–1585:L’esperieza inglese(The English Experience), edited by Michele Ciliberto and Nicholas Mann, pp. 125–156. Florence: L. S. Olschki. (Corrects Johnson’s claims that Digges anticipated Bruno and possibly influenced Bruno on his conception of an infinite universe.)Google Scholar
- Hall, A. R. (1952). Ballistics in the Seventeenth Century. Cambridge: Cambridge University Press.Google Scholar
- — “Thomas Digges.” Letter to the Times Literary Supplement, 5 April 1934, p. 244. (Corrects Cooper’s article in the Dictionary of National Biography.)Google Scholar
- Johnson, Franics R. and Sandford V. Larkey (1934). “Thomas Digges, the Copernican System, and the Idea of the Infinity of the Universe in 1576.” Huntington Library Bulletin, no. 5: 69–117. (Reproduces the 1576 edition of “A Perfit Description” from a copy of A Prognostication everlastingein the Huntington Library.)Google Scholar
- Koyré, Alexandre (1957). From the Closed World to the Infinite Universe. New York: Baltimore: Johns Hopkins Press. (See esp. pp. 35–39 where he also corrects Johnson on Digges’s conception of an infinite space, which Digges conceived in theological terms.)Google Scholar
- Neale, J. E. (1958). Elizabeth I and Her Parliaments. New York: St. Martin’s Press.Google Scholar
- Webb, H. H. (1965). Elizabethan Military Science. Madison: University of Wisconsin Press.Google Scholar
- Westman, Robert S. (2011). The Copernican Question. (See esp. pp. 268–280 where he explains the astrological context for the reception of the Copernican theory.)Google Scholar