Light of Reason, Light of Nature. Catholic and Protestant Metaphors of Scientific Knowledge

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Light of Reason, Light of Nature. Catholic andProtestant Metaphors of Scientic Knowledge

William B. Ashworth

Science in Context / Volume 3 / Issue 01 / March 1989, pp 89 - 107DOI: 10.1017/S0269889700000739, Published online: 26 September 2008

Link to this article: http://journals.cambridge.org/abstract_S0269889700000739

How to cite this article:William B. Ashworth (1989). Light of Reason, Light of Nature. Catholic and ProtestantMetaphors of Scientic Knowledge. Science in Context, 3, pp 89-107 doi:10.1017/S0269889700000739

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Science in Context 3, 1 (1989), pp. 89-107

WILLIAM B. ASHWORTH, JR.

Light of Reason, Light of NatureCatholic and Protestant Metaphors of

Scientific Knowledge

The Argument

Many of the epistemological issues that occupied natural philosophers of the seven-teenth century were expressed visually in title-page engravings. One of those issuesconcerned the relative status to be accorded to evidence of the senses, as comparedto knowledge gained by faith or reason. In title-page illustrations, the variousarguments were often waged by a series of light metaphors: the Light of Reason, theLight of Nature, and the Lights of Sense, Scripture, and Grace. When such illustra-tions are examined with the authors' theological views in mind, it becomes apparentthat in the first half of the seventeenth century, Catholic authors favored the Light ofReason as a source of truth, while Protestant authors favored the Light of Nature.Since by the end of the century it was widely accepted by scientists of all religiouspersuasions that certain knowledge must be grounded in sense evidence and thedirect study of nature, one might argue that in this instance Protestantism wasresponsible for nurturing an important development of the Scientific Revolution.However, the skewed nature of the sample (the Catholics who used light metaphorswere mostly Jesuits; the Protestants who did so mostly alchemists) and the largenumber of counterexamples available (many Catholic scientists believed in theascendancy of the senses but failed to engage in metaphorical warfare) mitigateagainst taking this offshoot of the Merton thesis too seriously.

The validity of the Merton thesis - whatever exactly that thesis may be - is not theconcern of this essay, although I will confess that I have yet to be convinced thatPuritanism and the rise of modern science were in any significant way related. But Iwill further confess that I have always been attracted by a basic corollary of the thesis:that being a Puritan made a difference to a Puritan's practice of science. Actually,what attracts me is a somewhat broader and milder thesis, that doctrinal differencesamong Christians were not irrelevant in the development of seventeenth-centuryscience. It is hard for me to believe that the huge theological chasms that separated,for example, Francis Bacon from Blaise Pascal, or Rene Descartes from RobertBoyle, are not germane to discussions of their differing scientific styles and achieve-ments. The problem is, of course, that it is not enough to find examples of individuals

90 WILLIAM B. ASHWORTH, JR.

who share the same theological views and have similar notions about natural philos-ophy, or individuals whose disagreements in religion are paralleled by scientificdifferences. One must find causal connections to make any:kind of an argument, andthe causal links are hard to come by. In fact, I have maintained elsewhere that forCatholicism, at least, a meaningful connection between the Catholic faith and thenature of Catholic science has yet to be demonstrated (Ashworth 1986). But I remainhopeful, and I would like here to enhance the search for connections between scienceand religion by increasing the data base, so to speak. I wish to address a body ofmaterial in which very few scholars - Mertonians or non-Mertonians - seem inter-ested, and that is the metaphorical imagery of seventeenth-century science. Inparticular, I would like to focus on two specific metaphorical images, the Light ofReason and the Light of Nature, and to argue that Catholic and Protestant scientistsused these images in different ways, revealing divergent attitudes toward senseexperience and the world of nature. I will not be able to demonstrate that thesevariations in imagery had any impact whatsoever on the course of the ScientificRevolution. But if and when a valid thesis should emerge that links the complex riseof modern science with specific Christian doctrines, I would hope that the icono-graphy of the issue would play an important part.1

Catholic Images of Reason, the Intellect, and the Senses

The images with which I am concerned are found primarily on the engraved titlepages or frontispieces that introduce many seventeenth-century works of science.Some of these title pages are quite familiar, such as those that preface Galileo'sDialogo or Bacon's Novum Organum. But it is not often realized how widespreadtitle-page illustrations were, or that they employ a visual language that is often quitespecific to the books they adorn and the issues there addressed. As an introduction toboth the genre and the specific metaphorical images that are to be our subject, Iwould like to examine the iconography of the title page of Bartolomeo Amici'scommentary on Aristotle's De Caelo, published in 1626.2 Amici was a Jesuit philos-opher who is little known today, although Edward Grant recently resurrected him ina discussion of seventeenth-century scholastic cosmology (Grant 1984). But Amici'stitle page is a wonderful visual introduction to Thomistic views of reason, sense, andhuman knowledge (see fig. 1).

The figure standing at the left is Pan, or Nature, and he represents common sense.We know that much with certitude, because the label "sensus communis" appearsbeneath. He bares his breast in a rather extreme fashion, revealing a pastoral naturescene within. Common sense, in the Thomistic scheme, is the first of the interiorsenses, responsible for uniting sense impressions and conveying them to the

1 This essay is distilled and refocused from several chapters of an ongoing book-length study ofseventeenth-century title-page imagery. How long this study is to be "ongoing" is a very good question.

2 The same title page appeared in his In Aristotelis Libros De Physico (Naples, 1626-29) and possibly inhis In universam Aristotelis logicam explicatio (Naples, 1622-24), which I have not been able to locate.

Light of Reason, Light of Nature 91

Figure 1. Engraved title page, Bartolomeo Amici, In Aristotelis Libros De Caelo et Mundo (1626).


imagination. Common sense has no faculty of abstraction and can grasp only particu-lars; the choice of Pan as personification seems apt. As we peer into Pan's heart, weare reminded that according to Aristotle the heart is the seat of the commonsensorium.3

Opposite Pan stands none other than Intellectus Agens, the Agent Intellect. Werethe label missing, we could still identify the figure by its attributes, since according toRipa's Iconologia (the standard Renaissance handbook of personifications) a figurewearing a crown and accompanied by an eagle must be Intelleto (Ripa 1611, 258).The agent intellect, according to Thomas Aquinas, is that part of reason which isresponsible for making sense experience intelligible and conveying it to the passiveintellect. It allows us to know changeable things unchangeably, and discern objectsfrom their likenesses. There are two especially interesting features about this particu-lar personification. First, Agent Intellect holds a mirror, which shows the very samescene that is revealed in the chest of Pan. The mirror represents phantasia, orimagination, which according to Avicenna is mirrorlike and mediates between theexternal senses and reason (Summers 1987, 96-100). Second, Agent Intellect basksin the glow of some external illumination. This is our Light of Reason.

The Light of Reason metaphor has its ultimate source in Aristotle, who hadcommented in the De Anima that the agent intellect is like a light (1931, 430a).Thomas Aquinas adopted the image enthusiastically and converted it from a simile toa metaphor. It is the light of the agent intellect, says Aquinas, that makes thephantasms of the senses intelligible.

Pursuing the metaphor further, he says that the intellectual light itself is nothingother than a participated likeness of the uncreated light. We achieve certain knowl-edge because the light of his countenance is upon us (Aquinas 1945, 1.79.4-5).Amici's image captures all of these Thomistic nuances, suggesting that the agentintellect is the divine light within, and that without God's help we would not be ableto achieve understanding.4

Before attempting to assess the impact of such an epistemology on seventeenth-century science, let us examine a second title page, this one from a work that is evenless scientific than Amici's, being a set of disputations by Roderigo Arriaga on thetheology of Thomas Aquinas (Arriaga 1643).5 Arriaga was also a Jesuit, professor atthe University at Prague for some years and then for many more its chancellor.6 Thetitle page is in some ways less accessible than that of Amici, but for that very reasonquite a bit richer in its imagery (see fig. 2).

3 See Summers 1987, which sheds considerable light on the classical and medieval background of oursubject, and informs much of my own discussion throughout.

4 It is important to understand that light metaphors are really something quite different from what iscalled light metaphysics, although the two are often conflated. For a discussion of the metaphysics of lightin this period, see Lindberg 1986.

5 The work ultimately extended to eight volumes. The title page was designed by Erasmus Quellin, acollaborator of Peter Paul Rubens.

6 Arriaga was primarily a philosopher, but he was a close friend of the mathematician (and fellow Jesuit)Gregorius St. Vincent, and it was Arriaga who was responsible for the publication of Gregorius' works.Arriaga also performed experiments on falling bodies with Giovanni Battista Riccioli. See Schmitt 1984.


tu OinrrH»rio

TOMVS PRiCONTIXR.T TRACTDK. DF.O \ ' \ O RT

A N T V K R PI A'.%X 'J»FIIISA PI.AN'IINIAKA

HAI.MI A.SAHI.S MIJRF.TM DC. Xl.lll

Figure 2. Engraved title page, Roderigo Arriaga, Disputationes Theologicae in Primam PartemD. Thomae . . . Tomus Primus (1643).


God dominates the scene, as he should. Seated on a throne and surrounded byvarious emblematic cherubs, he rests his foot on the earth, evoking Isaiah 66:1:"Thus saith the Lord, The heaven is my throne, and the earth is my footstool." Twobeams of light descend from God. The one on the left illuminates a radiant figure witha sun on his or her breast; the beam carries the words "In Lumine tuo videbimuslumen" (In your light we shall see light) from Psalm 36:10. The figure probablyrepresents Contemplation, the highest of the human faculties, although the motif ofthe sun on the breast is also characteristic of Virtue. On the right are two figures. Thelarger wears a veil, a characteristic attribute of Religion or Theology, and the lightbeam says "Fide Magistra" (guided by faith). She is writing, and holding her inkpot isa very youthful Reason, identified by a sash that says "ratione ministra" (assisted byreason). Reason is literally here the handmaiden to Theology, but interestingly,neither has anything to do with Contemplation's direct experience of the divine. Toemphasize this point, the artist places below the standing figures two vignettes; theone on the right, below Theology, shows a cherub trying to observe the sun byreflection, with the motto "Nunc in Aenigmate" (now obscured) while below Con-templation is an eagle observing the sun directly, with the motto "Tune facie adfaciem" (then face to face). The mottoes are, of course, from 1 Corinthians 13, andthe title page leaves the carefully crafted impression that Reason and Theology lookthrough a glass darkly, whereas Contemplation sees God face to face.7

The allegorical title pages of the Amici and Arriaga works have rather differentaims; one compares sense to reason, the other compares reason and faith to thebeatitude of the divine vision. But there are similarities in the messages conveyed.Both suggest the importance of illumination in achieving certain knowledge. Bothdownplay the importance of sense experience and the evidence of nature in establish-ing truth. Neither, however, seems to be specifically addressing the question ofscientific knowledge. To find that question explicitly raised, we may turn to a morefamiliar work by a better-known scientist - Rosa Ursina (1626-30) by ChristophScheiner. He too was a Jesuit, and in the fifteen years before writing this book he hadbeen involved in a bitter and protracted controversy with Galileo - ostensibly overcomets and sunspots, but at a deeper level over the place of sense experience inscientific knowledge. In the frontispiece to his book, Scheiner seems to have formal-ized his epistemological views in an unforgettable visual display (see fig. 3).

The Rosa Ursina is a book on sunspots, and, not surprisingly, Sun is the centralimage, blemished with spots and surrounded by the petals of a rose - one of thedevices of Scheiner's patrons, the Orsini family. The sun serves iconographically hereas a source of light, and it is counterpoised to another source of illumination at thetop, Divine Light. Two beams emanate from each of these sources, and together they

7 It is possible that the figures of Contemplation and Theology play dual roles here, which is not unusualin title-page allegories. The subject of Arriaga's first volume is the Trinity, and the two figures stand at thecorners of a triangle whose third vertex is occupied by God himself. So one could argue that they alsosymbolize Christ and the Holy Spirit. But while the lefthand figure is youthfully Christ-like, it is difficult toread too much of the Holy Ghost into the veiled figure of Theology.


Figure 3. Engraved frontispiece, Christoph Scheiner, Rosa Ursina sive Sol (1626-30).


represent what we might call the four lights. The ray at top left, which descends fromthe Glory, is the Light of Sacred Authority, or Scripture; the ray at top right, from thesame divine source, is the Light of Reason. The sun also is a source of light, andhence truth; but it is, quite literally, truth of a lower order. At bottom left, we see theLight of Profane Authority, and at bottom right the Light of Sense.

Before looking at these images more closely, we should note the origin of thefour-lights metaphor, for it does not stem from either Aristotle or Aquinas but ratherfrom Bonaventure. In his Retracing the Arts to Theology, Bonaventure distinguishedfour lights: (1) the light of mechanical art, which he also calls the external light; (2)the light of sense perception, or the lower light; (3) the light of philosophicalknowledge, or inner light; and (4) the light of sacred Scripture, or higher light. Thelast has its source directly in God, the Father of Lights (Bonaventure 1960-70,3:13-20). Bonaventure immediately proceeded to complicate his metaphor by sub-dividing and then redefining his lights, so Scheiner did not hesitate to run the lightsthrough his own prism, substituting profane authority for the mechanical arts, andmodulating philosophy into reason. He also drew on his Thomistic heritage andprovided reason with divine illumination. The net result is a remarkable epistem-ological image. Scheiner was clearly telling us (and Galileo) that sense evidence isinferior to the more certain knowledge of reason and Scripture.

Scheiner underscored this point with a delicious - indeed malicious - touch. HisLight of Sense is represented emblematically by the telescope, which is casting fuzzyimages of sunspots on a piece of paper. By themselves, these sensory images produceonly confusion. If we now look at the higher Light of Reason, we see that the eye isdirecting the hand to draw sunspots on another piece of paper, and these sunspots arecrisp and clear. Reason alone, says Scheiner, allows us to comprehend the newphenomena of the heavens; observation by itself will never lead to completeunderstanding.8

Scheiner's image of the four lights was appealing to his fellow Jesuit scientists,since it captured so well the Jesuit belief that the evidence of the senses, unlessilluminated by reason and natural philosophy, is insufficient to contradict Scripture,especially as concerns the mobility of the earth.9 Fifteen years after Scheiner createdhis visual metaphor, Athanasius Kircher resurrected it for the title page of his treatiseon optics, the Ars Magna Lucis et Umbrae of 1646 (see cover illustration of this issueof Science in Context). Most of the elements of that engraving are quite different fromthese of Scheiner, but the four lights are retained, placed exactly where Scheiner hadplaced them. Kircher robbed Reason of some of its splendor by snuffing out thedivine light, which was reserved for Scripture alone; but he still presented Reason as

8 The Scheiner frontispiece was also discussed in Ashworth 1985, 185-86, where it was placed in adifferent context - that of the publications of Galileo and Orazio Grassi, and the earlier works of Scheiner.At the time of this earlier writing I had not yet been illuminated by Bonaventure.

9 My comments on Scheiner give a slightly different picture from that of Peter Dear (1987), who givesScheiner greater credit for accommodating experience, especially the singular experience, into scientificknowledge.


superior to Sense. He also preserved Scheiner's emblem for Sense, the telescope; andlike Scheiner's, Kircher's telescope fails utterly as a solitary source of knowledge.

These four title pages, taken collectively, present an interesting view of Jesuitepistemology in the age of Galileo. Several of them suggest that reason is theultimate source of scientific knowledge, since it is divinely inspired. Several suggestthat reason is still only a handmaiden. And all of them give a minor or nonexistentrole to sense experience. To a Scholastic, sense evidence was important; without itthere could be no knowledge. But sense evidence by itself provides only phantasms,cloudy images that are the source of confusion rather than light. The assistance ofdivine light is required to make sense of the senses, to produce understanding in theintellect.10

There is a limit, however, to what such metaphors can tell us about Catholicscience. They tell us a great deal about Jesuit science, but there were a number ofCatholic scientists who would and did disagree with such an interpretation of senseevidence: Galileo is the obvious candidate; but we could also include Pierre Gas-sendi, Marin Mersenne, Rene Descartes, and a host of others. So this placing inopposition of the Light of Reason and the Light of Sense should not really beportrayed as a particularly Catholic attitude. Nevertheless, it is interesting that aboutthe same time a number of Protestant scientists were employing similar-appearinglight metaphors of their own, but ones that were rather differently polarized. Let usconsider one of them.

Protestant Images of Grace and Nature

Oswald Croll's Basilica Chymica was published in 1609, in the last year of his life. Itproved to be one of the most influential alchemical tracts of the century, goingthrough numerous editions and inspiring a great deal of discussion, pro and con.Croll was a Calvinist, and indeed he worked in a field that was to become an almostexclusively Protestant domain. Most of the expanse of his title page (see fig. 4) istaken up by portrait vignettes of Hermes, Roger Bacon, and others; but for us therelevant images are the circular diagrams at top and bottom center. The top emblemis identified as the Light of Grace, and it comprises the Trinity - Father, Son, andHoly Spirit - surrounded by the angelic orders. The lower device is more interesting,since it is an emblematic novelty; it is the Light of Nature. It includes various trinitiesof its own-the three kingdoms, animal, vegetable, and mineral; three elements, air,fire, and water; the triad of soul, body, and spirit; and the symbols for the alchemicaltriaprima, sulfur, mercury, and salt. It is noteworthy that the tiny alchemist to the leftof the emblem is bathing directly in the light of Christ Incarnate (Hannaway 1975,plate I).11

10 This summary, based on the imagery presented, is somewhat at variance with the conclusions ofRivka Feldhay (1987), who in an illuminating article argues for a more ecumenical view of Jesuitepistemology and emphasizes the Jesuits' willingness to depart from strict Thomism.

11 Hannaway uses the Croll title page as his own frontispiece and accompanies it with a detailedexplication, on which I have not improved.


These certainly form an intriguing pair of images, quite different from the scholas-tic metaphors we have been looking at, and it behoves us to ask from whence theycame. Fortunately, most of the spade work in this case has already been done byOwen Hannaway in his perceptive study of Croll and Andreas Libavius. The meta-phor of the two lights, Grace and Nature, originated with Paracelsus. The path tosalvation, for Paracelsus, was illuminated by the Light of Grace, and the guide forthat path was Scripture. The path to knowledge in this world was illuminated by theLight of Nature, and the guide was the Book of Nature. Although Paracelsus in hisearly years seems to have placed the Light of Nature in a secondary role (salvation ofthe soul is more important than healing the body), by the time of his AstronomiaMagna (1537), he seems to have given both lights an equal status in their own realms.And interestingly, both are divine. The Light of Nature is God's gift to man. AsParacelsus put it: "The Father has set us in the light of nature, and the Son in theeternal light. Therefore it is indispensable that we should know them both" (Hanna-way 1975, 6-8; quotation, p. 8).12

The Light of Nature is a striking metaphor because it elevates the study of natureto a new plane, and it totally ignores the role of the intervening faculties that occupiedAristotle and his commentators. When Paracelsianism underwent its Protestantrevival in the early seventeenth century, the doctrine of the two lights became apopular device, both as a poetic metaphor and as a visual image. In the lengthypreface to his book, Croll himself emphasizes the importance of the two lightsdepicted on his title page. The Light of Nature, he says, makes a true philosopher,and the Light of Grace begets a true theologian, and in these two lights we are to walkand spend our short time, as he puts it (Hannaway 1975,9). Subsequent chemical andalchemical writers found the concept equally attractive. Johann Daniel Mylius, whowas a member of the alchemical circle that included Michael Maier, took both Crollemblems as starting points and elaborated them considerably for the title page (notillustrated here) to his Opus Medico-Chymicum (1618).13

The Light of Grace emblem has become unrecognizable and seems now torepresent the Light of the Occult; but the Light of Nature device is much as Crollconceived it, with some additions. The additions are interesting. Around the outerrim is the phrase "Omnia ab uno, omnia in uno, omnia per unum" (All from one, allin one, all through one) - obviously, elements of the Light of Grace have beenincorporated into the Light of Nature here. And on either side kneel the alchemistHermes and the physician Hippocrates, in the act of prayer, illuminated by Godwhile investigating nature. This is a different, and most effective, way of representingthe Calvinist belief that the Light of Nature, because its source lies in God, providescertain truth.

12 Hannaway actually traces the metaphor much further back, through Renaissance and patristicNeoplatonism all the way to Paul and Plato. I have some doubts about this; light symbolism is quiteancient, as is light metaphysics, but Paracelsus' particular interpretation seems to be sui generis.

13 To my knowledge, the title page has not been reproduced in secondary literature; I examined thecopy at the University of Wisconsin. Mylius is discussed, but only in passing, in Read 1966.


Figure 4. Engraved title page, Oswald Croll, Basilica Chymica (1622?)


Ars Vitraria Experimentalis of 1679 (see fig. 5). In the genre of title-page engraving,this is High Baroque overkill - one needs a magnifying glass to read all the tiny labels- but the elements of interest to us are reasonably evident. The ultimate source of allknowledge is Lux Veritatis, the Light of Truth, at upper left. Mind uses the lens ofReason to focus that light and kindle Lumen Naturae, the Light of Nature (it is ofinterest that the medieval distinction between lux and lumen is preserved here).Experience then uses the Light of Nature to turn wisdom into scientia (knowledge).14

A rather novel exercise in epistemology is reflected in Kunckel's engraving. TheLight of Grace is nowhere to be seen. Reason is not a light now, but an agent; and it isExperience that ultimately produces truth, employing the Light of Nature. Reasondoes not operate on sense evidence; Experience does. Knowledge, by the laterseventeenth century, has become a product of the laboratory.

It would be presumptuous to make a trend out of Croll, Mylius, and Kunckel, butit is intriguing that all three were Protestants, and all, with their light metaphors,extolled the Light of Nature more than the Light of Reason. It is even moreinteresting that when one studies other title-page motifs - such as "NatureRevealed," or "Mother Earth"15 - one discovers that when nature is being exalted asthe source of truth, the author, far more often than not, is Protestant.

There was one other Protestant variation of the two lights metaphor that wascompletely divorced from the alchemical tradition, and we might call it the Baconian,since it seems to have originated with the Novum Organum (1620). It is well knownthat Bacon was quite fond of light metaphors, especially in his discussions of Experi-ments of Light and Experiments of Fruit. On the title page to his Sylva Sylvarum(1629) he used a light motif in a very unusual way (see fig. 6).16 An illuminating flashdescends from the divine glory, accompanied by a quotation from Genesis ("AndGod saw the light, that it was good"), and this light shines on an indistinct globe,identified as the Mundus Intellectualis (globe of the intellect). It seems at first glanceas if Bacon is extolling the Light of Reason in a way very similar to that in Jesuitimagery.

But when one reads the Novum organum, from which the emblem of the intellec-tual globe derives, it is clear that Bacon's light is something quite different. ForBacon, the light of the intellect comes up from the senses. To derive truth fromnature, one must in fact silence the intellect and focus on the facts of nature,"receiving the images simply as they are." Bacon's most widely used metaphor forthe intellect is an uneven mirror, which distorts the rays of the senses. The sensesthemselves contribute much less error, and these errors can be sorted out. So by hisintellectual light, Bacon actually means the "Light of Nature and Experience,"which is the phrase he most often employs when discussing the pursuit of certain

14 On Kunckel, see Partington 1961, 361-77, which has a discussion of Kunckel's chemical work, ArsVitraria, but nothing on the title-page illustration.

15 These are the subjects of chapters in the study cited in note 1.16 The Sylva Sylvarum was first published in 1626, with the engraved title page dated 1627. For the

second edition the same engraving was used, with the 1627 date reworked to 1629.


Figure 5. Engraved title page, Johann Kunckel, Ars Vitraria Experimentalis (1679).


Tit. ilridit (2)eut luctm. ||| |; auod. tft-et- oona-2

Figure 6. Engraved title page, Francis Bacon, Sylva Sylvarum (1629).


truth. When God gave man his intellectual light, he gave man the ability to ascertaintruth by induction from observations gathered from nature. Bacon truly saw reasonin a new light (Bacon 1620, preface, aphorism 1:55, 74).

It is tempting to see in this Protestant, alchemical, Baconian insistence on theprimacy of nature some deep significance, especially since Catholic scientists, or atleast Jesuit scientists, omitted nature from their scheme of illumination and gavesense experience a subsidiary role. If one studies only the visual use of the Lights ofReason and Nature, it does seem as if a division along sectarian lines is apparent andmeaningful. But one should always remember that even if light metaphors can bedivided up on the basis of religion, that is not necessarily true of scientists. Therewere a number of important figures in the Scientific Revolution who came to believethat the evidence of the senses is as important, and as valid, as the workings of theintellect in establishing scientific knowledge, and they showed no propensity for anyparticular sect or creed. Since this is a paper about images, I will argue this importantand final point by referring to two more title-page engravings, although I will have todepart from the world of light metaphors to do so.

Jan Hevelius published his Selenographia in 1647, the year after Kircher's ArsMagna Lucis et Umbrae. The timing is significant, for on the title page Heveliusseemed to take direct aim at the assertions of Kircher and Scheiner that sense was anorder of knowledge inferior to reason. The title page (not illustrated here) isdominated by two large standing figures. Alhazen is at the left, with a ray-tracingdiagram in his hand, and Galileo is on the right, holding a telescope. On an obviouslevel they represent the sciences of optics and astronomy; but they mean somethingmore here, and since that meaning might not be obvious, the artist provided furtheridentification. On the plinth beneath Alhazen's feet is a tiny vignette of a skullcapand the word ratione (by reason). On Galileo's plinth is an eye and the wordsensu (bysense). Alhazen and Galileo epitomize reason and sense. For the Jesuits, reason andsense were only two of the four sources of knowledge, and they stood on differentlevels. For Hevelius, they are the only two sources of truth, and they have equalstatus. What was Hevelius' religious affiliation? No one seems to know for sure. Hewas certainly religious, but more detail is lacking in both his own works and those ofhis biographers. Whatever his theological views, they were unobtrusive, and it seemscertain that his exaltation of sense had little to do with either Scholastic or Reformistviews of epistemology.

The second example, or counterexample, is the frontispiece to a book published in1670, Agostino Scilla's La Vana Speculazione disingannata dal Senso (see fig. 7).Scilla was more obviously a Catholic, but he was a Neapolitan Catholic, which is notquite the same thing. His fossil treatise, which has languished in the shadow of themasterpiece of Nicolaus Steno, is a quite remarkable defense of the organic origin offossils; but the frontispiece is even more remarkable in the light of the metaphors wehave been pursuing. Scilla, not so incidentally, was an artist and seems to havedesigned the engraving himself. The illustration shows an outdoor scene; not much ofthe landscape is visible except for a slope in the right foreground that is littered with


fossils. The rest of the space is dominated by two figures, one wispy and wraith-like,with a tenuous hold on reality; the other solid and down-to-earth, with the eye ofreason firmly embedded in his breast. What do they represent? The very title of thework provides the answer. The will-o'-the-wisp is Vain Speculation, and she is beingdisabused of her false preconceptions by Sense. Natural philosophers have main-tained that fossils are sports of nature, productions of the earth; but the physicalevidence proves that they are the remains of formerly living creatures. Sense hastaken over the eye of reason and has become the principal arbiter of scientific truth.This frontispiece and that of Scheiner stand at opposite poles of the Catholicscientific experience.

Conclusion

The goals of this essay have been limited. First, I have tried to demonstrate thatepistemological issues of seventeenth-century science were frequently expressedvisually in title-page engravings, using imagery that is often revealing of the author'sposition. Second, I have tried to argue - in the specific case of the metaphors of theLights of Reason and Nature and their accompanying Lights of Sense, Scripture, andGrace - that certain Protestant scientists used these metaphors differently fromcertain Catholics, and that these differences may reflect real differences in attitudestoward the interpretation of sense evidence. It is tempting to extrapolate thesefindings into a mini-Merton thesis: that Protestant scientists placed greater relianceon the direct study of nature, and this faith in the senses fostered one of the mostimportant developments of the Scientific Revolution. I choose not to be so tempted,for reasons that I hope are obvious. I have dealt with two very limited subsets ofCatholic and Protestant science: Jesuits, on the one hand, and alchemists, unitedhere by forced marriage to Bacon, on the other. This is a skewed sample at best, andit cannot be unskewed, because there are no other title pages to examine; these twogroups form the sum total of all seventeenth-century scientists whose title pagesdepicted the Lights of Reason and Nature in some form. Moreover, as I have tried toshow with the examples of Hevelius and Scilla, there were Catholic scientists whoavoided light metaphors but still placed great reliance on sense evidence; there werestill others, such as Galileo and Descartes, who did not engage in metaphoricalwarfare at all and believed even more strongly in the importance of evidence derivedfrom nature. So one cannot really draw any strong conclusions from this limitedstudy. But I do suspect that if one were to analyze all of the epistemological imagesand metaphors from seventeenth-century title pages in the light of the authors'theological positions, then real sectarian differences might well emerge. Whetherthis would shed any light at all on the rise of modern science is, at this point, anyone'sguess.


Figure 7. Engraved frontispiece, Agostino Scilla, La Vana Speculazione disingannata dal Senso (1670).


Acknowledgement

All illustrations, courtesy of the History of Science Collection, Linda Hall Library,Kansas City.

References

Amici, Bartolomeo, 1626. In Aristotelis Libros De Caelo et Mundo. Naples:Roncaliolum.

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Department of HistoryUniversity of Missouri

Documents

Light of Reason, Light of Nature. Catholic and Protestant Metaphors of Scientific Knowledge