Newton and the perils of the imagination

In the 17th century, there were two contradictory attitudes to the imagination or ‘phantasy’. For many it was valued as the source of wit and invention; but for others it was the basis of deception, superstition, and mental illness.

It was John Calvin, a century earlier, who had warned that the mind was a dungeon and a factory of idols. English puritan writers followed in his wake, cautioning against the seductive tendencies of the unregenerate imagination, which tempted believers to mistake for the works of God what were really only the fictions of their own devising. This attitude was then absorbed by English natural philosophers such as Francis Bacon, who argued that the imagination was the underlying source of many of the ‘idols’ that bedevilled the human mind.

Isaac Newton (1643 – 1727) stood within this tradition.

As a student at Cambridge, he performed a series of experiments designed to test the power of his imagination, based on his reading of works by natural philosophers Joseph Glanvill and Robert Boyle (both just a few years his senior). Newton ‘heightened’ the power of his fancy by looking at the sun in different positions in order to ‘tenderize’ his sight. Extraordinarily bright after-images imposed themselves on him whether he wanted them to or not, and after lying in bed with the curtains drawn for several days, he concluded that ‘the tenderest sight argues the clearest fantasie of things visible & hence something of the nature of madnesse & dreames may be gathered’.

Newton’s scientific investigations were paralleled by his theological critique. In a series of remarkable writings circa. 1661 – 1665 he analysed the actions and morals of the Desert Fathers and their efforts to resist temptation. Newton argued that they had in fact actively encouraged their own carnal imaginations; they had wrongly believed that they could imitate the experience of Jesus in the Judaean Desert and thwart the temptations offered by Satan. But the techniques they deployed to tame their own imaginations could only end in defeat, and their extreme and unnatural mental and corporeal regimens inevitably inflamed the imagination, leading inexorably to the lustful thoughts they professed to despise. In a very short time, monks trained in these practices and driven mad by both day and night-time visions of naked women, formed religious communities that were, Newton concluded, cesspits of fornication.

To Newton, the imagination was always liable to tempt the unwary into idolatry, idleness, and lust. The only way to avoid its baneful effects was to be relentlessly active, focusing on useful, rational, and godly endeavours such as mathematics, natural philosophy, and theology.

The dangerous consequences were not limited to the impact on the individual. Since the listless and undisciplined scientific mind was prone to produce a slew of systems and hypotheses that were merely the seductive products of human ingenuity, the whole scientific community would then be beset by the anarchy of mere opinion.

Newton’s fear and loathing of the effects of the imagination was embedded in the influential methodological advice he bequeathed to eighteenth-century science, the Principia Mathematica. In the ‘General Scholium’ added to the second (1713) edition his famous statement ‘Hypotheses non fingo’ (‘I do not feign hypotheses’) summed up his credo in three words. The most strident statement was then made in the ‘Preface’ to the 1713 edition written by the mathematician Roger Cotes, who noted that “by taking the foundation of their speculations from hypotheses”, Cartesians drifted off into dreams. By doing so “they merely put together a romance, elegant perhaps and charming, but nevertheless a romance”.

But within a few decades of Newton’s death, opinions on the imagination had changed – and in a way which has its own irony.

Numerous authors paid homage to Newton’s incessant condemnation of systems, hypotheses, and untested theories. However, the argument went, brilliant hypotheses and theories of some kind surely had some role in guiding both experimenters and theorists in their work. By the middle of the eighteenth century the reputation of the scientific imagination was experiencing a remarkable resurgence. And the great exemplar of the newly invented ‘scientific genius’ was none other than Isaac Newton himself.

In 1767, William Duff argued that Newton’s discoveries showed

“the prodigious compass of that imagination, which could frame and comprehend such sublime conceptions [but at the same time] evince the profound depth of penetration and strength of reason, which by a kind of divine intuition, could discern and demonstrate truth.”

Seven years later Alexander Gerard claimed that it was Newton’s vast imagination that gave him “so great a command over the natural and intellectual world, that, in his philosophical enquiries, he misses no experiment which is necessary for promoting his investigation.”

In placing the imagination at the centre of their pioneering accounts of scientific genius, Duff and Gerard paved the way for modern ideas about scientific creativity. However, in doing so, they had decisively moved away from the religious and scientific concerns about the imagination which had so exercised their heroes, and which belonged to a different age.

Featured image credit: Portrait of Sir Isaac Newton, oil on canvas [M. Keynes, Iconography of Sir Isaac Newton, X], 1250 x 990mm., English School, [c.1715-1720]. Public domain via Wikimedia Commons.