JOHN FIELD (c.1520-1587)
'The proto-Copernican of England'
A small wooden plaque, made with a piece of timber from Nelson's flagship, HMS Victory, is fixed to the internal wall of the Parish Church of St Michael, East Ardsley, near Leeds. The inscription, in gold lettering, declares:
HE WAS THE FIRST
ASTRONOMER IN THIS
COUNTRY TO MAKE KNOWN
THE DISCOVERIES OF
A place of worship has stood on this site since since the mid-12th century and, though in 1879 the existing church was pulled down, because of fears over its safety, the porch of the present building is probably in the same spot as that of the 16th century church. Field (sometimes spelt 'Feild'), who described himself in his will as "John Feild of Ardslow, fermor, sometymes studente in the mathematicall sciences', gave directions that his body should be interred 'in the church porch at Ardsley, where I am now a parishioner".
What makes Field intriguing is that he was the first person in England, so far as is known, to publish an astronomical almanac based on the assumptions of Copernicus: Ephemeris Anni 1557, Currentis Iuxta Copernici et Reinhaldi Canones Supputata. In the introduction, Field criticised the errors of his predecessors, who had relied on the ptolemaic Alphonsine Tables for their almanacs. This new almanac, he declared in early 1556, followed "the authority of N.Copernicus and Erasmus Reinhold, whose writings are founded and firmly built on true, sure, clear proof". He was way ahead of his time. The magnum opus of Copernicus, On the Revolutions, had only come off the press in Nuremberg thirteen years earlier (1543); the Prutenic Tables of Reinhold, based on Copernicus, had been published in Germany a mere five years before (1551).
Before Copernicus, the standard view was that the Earth was fixed at the centre of the cosmos and the star-studded sphere revolved around the Earth daily in a westerly direction. The relative motion of the Sun, Moon and five known planets was explained by an assumption that they were revolving about the Earth, but at a closer distance and according to a complex pattern described by reference to a theorized gearing system - Ptolemy's deferents and epicycles. Copernicus, by contrast, established his system on radically new premises. He argued that the apparent motions of the celestial bodies were due to a daily rotation of the Earth about a north-south axis and an annual revolution of the Earth about the Sun. The planets too were revolving around the Sun. Only the Moon was still held to be revolving about the Earth.
Few astronomers were convinced of the correctness of the Copernican assumptions. They found it hard to envisage that a body as massive as the Earth could rotate at such a prodigious speed. Even harder to swallow was the notion that the Earth was a mere planet, hurtling around the Sun. Beside all the scriptural objections to a moving Earth, there was no discernible parallax effect on the position of the stars, which one would have expected to exist, if the placement of the observer was so dramatically changing over the course of the year. Nevertheless, astronomers began to recognise superiority of the Copernican approach - especially as supplemented by the tables of Reinhold - for accurately calculating future positions of the heavenly bodies. It was possible to construct tables in this fashion without accepting the literal truth of the heliocentric theory or the terrestrial rotation. Indeed, the very preface of On the Revolutions seemed to suggest this. It advised the reader that Copernicus's hypotheses "need not be true nor even probable; it is sufficient if the calculations agree with the observations".
It is possible that Field was a follower of Copernicus in this sense. Nothing is known of his true personal opinion on this matter. He prepared the Ephemeris at the suggestion of John Dee, who had become acquainted with Copernican ideas during his travels on the continent. Dee, however, left no published evidence that he accepted the literal truth of these ideas. Like many scholars of their time, Dee and Field were interested in planetary positions for astrological purposes. Indeed, it may have been the dabbling with horoscopes that got them into trouble with the authorities, for on 1st June 1555 John Dee and Field were committed into custody and on 5th June the Privy Council authorised their examination "uppon suche poyntes as by thier wisdomes they shall gather out of thier former confessions towching thire lewde and vayne practises of calculing and conjuring". It was alleged, moreover, that witchcraft had been used to wreak revenge on two of the children of their chief accuser: immediately upon the accusation - one child had been struck dead and the other rendered blind! The chief offence that Dee and Field had committed was that they had drawn up horoscopes (or 'nativities') for Queen Mary, her husband Philip, and Princess Elizabeth.
Whereas Field's interest in astrology was not unusual amongst scholars of his time, his reliance on the 'authority' of Copernicus marked him out as a trailblazer. The tables of Reinhold - based on those of Copernicus - were noticeably more accurate than the ptolemaic Alphonsine Tables then in use. Was it simply for this reason that Field spoke of the superiority of their foundations? This was the prevalent attitude, even forty years later, amongst English astronomers generally. Thomas Blundeville summed it up succinctly in his 'Exercises' (1594), when he commented: "Copernicus by way of supposition, and not that he thought so in deede: who affirmeth that the earth turneth about, and that the sunne standeth still in the midst of the heavens, by helpe of which false supposition he hath made truer demonstrations of the motions & revolutions of the celestiall Spheares, then euer were made before ...".
In 1609, after the title page of his book 'New Astronomy', in an open letter to Peter Ramus, Johannes Kepler asserted that "[Copernicus] ... considered his hypotheses true ..." and that the Lutheran theologian Andreas Osiander had placed the misleading preface upon the frontpiece of De Revolutionibus, "Copernicus himself being dead, or certainly unaware of this".
The most advanced astronomers of Field's time treated Copernican assumptions with respect and caution, in equal measure. In Robert Recorde's 'Castle of Knowledge' (1556), an instructional dialogue between a Master and a Scholar (or pupil), the Scholar says, after hearing that Copernicus has resurrected the ancient heliocentric theory of Aristarchus, "Nay syr in good faith, I desire not to heare such vaine phantasies, so farre againste common reason, and repugnante to the consente of all the learned multitude of Wryters, and therefore lette it passe for euer, and a daye longer". The Master, however, chides this closed-minded attitude, saying "You are to yonge to be a good iudge in so great a matter: it passeth farre your learninge, and theirs also that are muche better learned then you, to improue his supposition by good argumentes, and therefore you were best to condemne no thinge that you do not well vnderstand: but an other time, as I sayd, I will so declare his suposition, that you shall not only wonder to hear it, but also peraduenture be as earnest then to credite it, as you are now to condemne it".
The modern expert of Copernicanism, Robert Westman confessed (in 1980) that "between 1543 and 1600, I can find no more than ten thinkers who choose to adopt the main claims of the heliocentric theory". These were "Thomas Digges and Thomas Hariot in England; Giordano Bruno and Galileo Galilei in Italy; Diego de Zuņiga in Spain; Simon Stevin in the Low Countries; and, in Germany, the largest group - Georg Joachim Rheticus, Michael Maestlin, Christopher Rothmann, and Johannes Kepler".
Field is not on this list and his view that Copernican writings are based on "true, sure, clear proof" remains ambiguous. Nevertheless, uncertainty remains. In 1862, Osgood Field, a descendant of John, published an essay on 'A few hitherto unpublished facts relating to John Field, "The proto-Copernican of England"', in which he spoke of "A treatise, in manuscript, on the management of great ordnance, in the Lambeth library, without date, but probably about this time, contains this remark: 'Mr. Felde taught me astronomie after Copernicus, the great astronomer'". Unfortunately, Osgood Field provided no catalogue reference and this manuscript has yet to resurface in the Lambeth Palace Library and possibly cast further light on the true opinions of the enigmatic mathematician, John Field.