1Henricus Regius and the Limits of Cartesian PhilosophyErik-Jan Bos (Dept. of Philosophy, Utrecht University)

Draft versionplease do not circulate. To appear in a French translation(Henricus Regius et les limites de la philosophie cartsienne) in: D. Kolesnik,Quest-ce qutre cartsien?, Lyon: ENS Editions, 2010.

In the spring of 1643 Henricus Regius met Princess Elizabeth of Bohemia at The

Hague. Elizabeth had read his physics as well as Descartes Meditations, but she

was left with several questions. Knowing that the Utrecht professor was an ardent

proponent of Cartesianism, she put the problem to him how the human soul can

interact with the body, if soul and body are distinct substances. Regius wavered the

question and suggested that she took the matter up with Descartes himself.1 He may

have agreed with Elizabeth that some core elements of Cartesian metaphysics were

not that clear and distinct at all, but surely he kept that to himself. And in any case,

he would not want to rob his friend from this excellent opportunity to get into contact

with the Princess Palatine. What happened in the years that followed is well known.

Elizabeth engaged in a correspondence with the French philosopher, and her inquiries

into the interaction of body and soul encouraged Descartes in writing his Passions de

lme. By contrast, Regius friendship with Descartes eventually exploded because of

their different views on, among other things, the relation between body and soul.

Dissociating himself from his former ally, Descartes bitterly remarked in the

Preface to the French translation of the Principia philosophiae (1647) that as far as

physics and medicine are concerned, it appears that everything he wrote was taken

from my writings but that he denied certain truths of metaphysics on which the

whole of physics must be based.2 The first assertion is exaggerated but true in that

Regius medicine and physics is wholly Cartesian. The second assertion is true to the

point that the Utrecht professor indeed largely rejected Descartes metaphysics.

Descartes most interesting claim follows next: the whole of physics (and medicine)

1 Elizabeth to Descartes, 6 May 1643, AT, III, p. 660-661. References are to the edition of Ch.Adam and P. Tannery, uvres de Descartes, New Edition, Paris, Vrin, 1964-1974, 11 vols; E.-J.Bos (ed.), The Correspondence between Descartes and Henricus Regius, Utrecht: ZENO, theLeiden-Utrecht Research Institute for Philosophy, 2002. Bos is online availabe at http://igitur-archive.library.uu.nl/. English translations are borrowed from J. Cottingham, R. Stoothoff, D.Murdoch and A. Kenny, The Philosophical Writings of Descartes: The Correspondence,Cambridge, Cambridge University Press, 1991, abbreviated as CSMK.2 AT, IXB, p. 19; CSMK, p. 189.

2must be based upon metaphysics. What would be the consequences of this claim for

labelling Regius as a Cartesian? Is it possible to reject the Cogito and its

accompanying metaphysics and still be Cartesian? One way to look at this is that it

depends on whether or not the theory collapses. For example, ancient and early

modern atomism comes in a variety of ways, but if an atomist admits that atoms can

be divided or denies the void, he does not adhere to atomism. Descartes himself is

quite clear: As metaphysics is the foundation of physics, one cannot accept his

physics and deny certain truths of metaphysics without falling into contradictions. On

of the most flagrant contradictions was, according to Descartes, the denial of the

immateriality of the human soul. Ever since Descartes, commentators appear to agree

with him that Regius is a dubious philosopher, at odds trying to conceal an atheistic

materialism. A clear indication of that would be the fact that Regius invokes Holy

Scripture to settle the dispute on the true nature of the human soul. In this paper we

will investigate to what extent that accusation, to be found in Descartes criticisms as

well as in modern literature, is justified. In my view, the appeal to Revelation is not

the obvious move of a libertine facing theological inquisitors, nor does it imply

philosophical incompetence. On the contrary, it is consistent with Regius theory of

mind and in accordance with his own philosophical principles. This result supports

the view, advanced in several recent studies, that Regius rightly concluded that

Cartesian physics and medicine does not collapse without certain metaphysical truths.

The Author of Cartesian Text Books

Shortly after his appointment as professor of medicine at Utrecht University Regius

introduced himself to Descartes, because, as he put it, he owed his new position to his

knowledge of Cartesianism.3 During the following years Regius made himself the

main advocate of the new philosophy in Utrecht. In fact, he was the first university

professor to teach Cartesian ideas and publish a number of disputations, which

together provide a fairly complete picture of Cartesian natural philosophy. It is

presumably this collection of disputations, afterwards published together under the

title Physiologia sive cognitio sanitatis (1641), which Elizabeth had read.4 In 1645

Regius submitted the manuscript of a proper textbook on natural philosophy to 3 Regius to Descartes, [8/] 18 August 1638, Bos, p. 5 (AT, II, p. 305-306).4 Regius, Physiologia, sive cognitio sanitatis. Tribus disputationibus in Academi Ultrajectin publicproposita, Utrecht, . Roman, 1641. The Physiologia is reprinted in Bos, p. 195-240. On Regiuslong term desire to publish a textbook, see Bos, p. 40.

3Descartes. After perusing the final chapter On man (De homine), Descartes was

shocked by its contents and threatened to dissociate himself publicly from Regius

should he publish that book. Regius, however, did not yield to Descartes, although

some paragraphs which Descartes had objected to in particular were left out when

Fundamenta physices appeared in 1646.5 This fact could not satisfy Descartes, who

distanced himself from the book and its author in the Preface of the French edition of

the Principia philosophiae (1647). Regius reacted by printing a broadsheet in which

he set forth his theory of mind, the Explicatio mentis humanae.

Although Regius embraced Cartesianism, he did not endorse every aspect of

Descartes philosophy. In the end Regius different ideas on method and metaphysics

made a break between the two men inevitable. Nevertheless, the Fundamenta

physices can be considered as a genuine Cartesian textbook of natural philosophy, and

Regius himself was the first to acknowledge his debt to Descartes in his last letter to

the French philosopher:

Pour vous, Monsieur, qui jai dj des obligations infinies,

vous me permettrez de vous remercier de la bont que vous avez

eue de lire mon livre [sc. the Fundamenta physices] ou pour

mieux parler, votre livre, puisquil est vritablement sorti de

vous.6

With this last remark Regius probably voiced Descartes main concern with

regard to the book. Already in 1641 he wrote Regius that, since the general public

would make no distinction between the two of them, he would have to scrutinize the

texts Regius intended to publish for ideas he was not prepared to defend as his own.7

Regarding the Fundamenta physices, Descartes worried that the public would

consider it as a supplement to his own Principia, from which a discussion of living

nature (plants, animals and man), was conspicuously absent.8 His fear was not

unwarranted: the Fundamenta physices was indeed seen as a Cartesian treatise, and in

5 Regius, Fundamenta physices, Amsterdam, L. Elzevier, 1646.6 Bos, p. 190 (AT, IV, p. 256).7 Bos, p. 64 (AT, III, p. 393-394). Cf. AT, VIIIB, p. 163 and AT, IXB, p. 19.8 Principia philosophiae, IV, art. 188; AT, VIIIA, p. 315.

4fact it remained the only Cartesian textbook that included a comprehensive study on

living nature until the posthumous publication of Descartes LHomme in 1662.9

The Appeal to Revelation

The Explicatio mentis humanae consists of 21 short articles, some of which give

expression to the ideas Regius had excluded from the Fundamenta physices.10 The

articles two, three and four contain the fundamental disagreements with Descartes on

the relation between body and soul. In the second article Regius states that, as far as

the nature of things is concerned, the human soul can be a substance, but could also

be a mode of a physical substance. Indeed, if extension and thought are attributes, it is

possible that both co-exist in the same subject. Although these attributes differ,

Regius claims that they are not necessarily distinct. The conclusion in article three is

then that those who believe that we clearly and distinctly understand the human mind

to be necessarily distinct from the body, are mistaken. The question on the true nature

of the human mind is solved in the fourth article. It claims that in many places in Holy

Scripture it is revealed that the mind is a substance, that is, an entity really distinct

from the body, and that it can subsist on its own, apart from the body. While that

conclusion may be doubted by those who rely on natural knowledge only, it is

indubitable as a result of divine revelation.

Regius statement that the mind could be a mode of the body, and that it is

only by revelation that we know that it is incorporeal and a distinct substance has

given rise to far-reaching speculations concerning his true convictions. According to

Descartes it implied a materialist account of the soul, and that the fourth article of the

Explicatio mentis humanae was no more than an ironic way to deceive theologians.11

Following Descartes, other Cartesians branded Regius an apostate, a renegade, who

would be too stupid to understand Descartes metaphysics. Even Regius most

9 Huygens, for example, valued Regius work very highly, even though he knew thatDescartes was less enthusiastic, see Huygens letters to Mersenne of 21 August and 12September 1646, in C. de Waard and A. Beaulieu (eds.), Correspondance du P. Marin Mersenne,Paris, CNRS, 17 vols., 1932-1988, vol. 14. p. 413, 450). On Regius book, see Th. Verbeek,Regiuss Fundamenta physices, Journal of the History of Ideas, 55 (1994), p. 533-551. It shouldbe noted that in his Passions de lme Descartes supplies a short outline of human physiologyin view of his theory of the passions.10 Descartes reprinted the Explicatio mentis humanae in his rejoinder Notae in programmaquoddam (1648), AT, VIIIB, p. 342-346. For the context of both publications, see Th. Verbeek,Descartes and the Dutch. Early Reactions to Cartesian Philosophy 16371650,Carbondale/Edwardsville, Southern Illinois University Press, 1992, p. 54-59.11 AT, VIIIB, p. 356.

5talented student Johannes de Raey, who acted as respondens during the disputations

of 1641 and who became an important Cartesian philosopher at Leiden University,

turned himself against his preceptor. Questioned about Regius by a Danish visitor in

1661, he replied that he formerly took Regius for a Socinian, but now for an atheist.12

De Raeys aversion from Regius even deepened over the years: in 1687, eight years

after Regius death, he declared that before Spinoza, with whom he shared various

errors, Regius corrupted philosophy.13

Recently, Fernand Hallyn argued strongly in favor of this traditional view on

Regius.14 Analyzing Regius Philosophia naturalis (1654),15 the second edition of

Fundamenta physices, in terms of dissimulation and irony he portrays the work as a

typically libertine attempt to propagate materialism and atheism. In Philosophia

naturalis Regius added a long introduction to his final chapter on man, in which he

refutes the core of Descartes metaphysics at length. Not surprisingly, the first

principle he attacks is the foundation of knowledge, the Cogito. Page after page

Regius argues against Descartes proofs for the immateriality of soul, advancing his

strong defense of the soul as a mode or an accident of the body. However, time and

again he reminds the reader that Revelation teaches us that the soul is an immaterial

substance. The disparity between the refutation of Descartes and the arguments in

favor of the (possibility of a) material soul on the one hand, and the appeal to the

Bible on the other, can, according to Hallyn, only be understood as a devious strategy

of the libertine, using the rhetoric of double truth in philosophy and theology.

Much can be said in favor of Hallyns decision to limit his study of Regius

works to the Philosophia naturalis. All too often it is overlooked that Regius final

views are to be found there. However, it needs to be underscored that the newly added

introduction to the chapter on man is highly polemic. In 1648 Descartes wrote a

refutation of the Explicatio, entitled Notae in programma quoddam. The Utrecht

professor replied to this with Brevis explicatio mentis humanae in the same year. 12 Olaus Borrichius, Itinerarium 16601665. The Journal of the Danish Polyhistor Ole Borch, H.D.Schepelern (ed.), 4 vols., Copenhagen/London, C.A. Reitzels Forlage/E.J. Brill, 1983, vol. I, p.43.13 See Th. Verbeek, Descartes and the Dutch, p. 73.14 See F. Hallyn, La Philosophia naturalis de Regius et l'criture athe, Libertinage et philosophieau XVIIe sicle, 9 (2005), p. 37-46; F. Hallyn, Descartes: Dissimulation et ironie, Genve, Droz,2006, p. 173-201. The view that Regius argued for philosophical materialism is widespread inliterature, see for another recent example H. Cook, Matters of exchange: commerce, medicine, andscience in the Dutch Golden Age, New Haven (etc.), Yale University Press, 2007, p. 246.15 Regius, Philosophia naturalis, Editio secunda, priore mult locupletior, et mendatior. Amsterdam,L. Elzevier, 1654.

6Regius reworked and extended the Brevis explicatio into the introduction to the

chapter on man in the Philosophia naturalis, rebuking all objections and remarks put

forward by Descartes in his Notae. Moreover, he also replied to the rejoinder to his

Brevis explicatio by the Groningen professor Tobias Andreae.16 As a result, Regius

counters one objection after the other, page after page, contrasting his opponents

views with arguments in favor of the soul as a mode.

The appeal to Revelation as a source of apodictic knowledge seems like a

Deus ex machina, as if his only intention is to pacify the theologians by feeding them

with a few Biblical quotations. Had that been Regius aim, he cut himself in the

fingers. He may have fooled some pious souls but certainly not the theological front

man of the Dutch Reformed Church, the Utrecht professor Gisbertus Voetius. Voetius

agreed with Descartes that some truths, among which the existence of God and the

distinction between the human soul and body, can be demonstrated by reason alone,

unaided by Biblical evidence. Indeed, according to Voetius to demonstrate those

truths is the principal aim of philosophy.17 Consequently, we have to reject Descartes

claim that Regius ultimately called upon the Holy Writ to reconcile with the Utrecht

orthodox theologians. Other contemporary accusations of atheism, e.g. by De Raey,

are not decisive either. That some took him for an atheist, does not make him one.

Finally, the appeal to Revelation would only be relevant and revealing if Regius

upheld the position that from a philosophical point of view we cannot escape the

conclusion that the soul is materialwhich he did not. In my view, there is no double

truth doctrine in Regius. The allegation that Regius dissimulates his true position

ignores the fact that he has good grounds for claiming that there are limits to

philosophical knowledge.

The Limits of Philosophical Knowledge

Even though Regius removed certain elements of his theory of mind from

Fundamenta physices, obviously he could not avoid the topic altogether. A crucial

statement is found early in the book when he discusses the principles of philosophy.

Apart from the general or material form of corporeal bodies, like movement, rest,

16 Tobias Andreae, Brevis replicatio reposita Brevi explicationi mentis humanae, sive Animaerationalis D. Henrici Regii [] Notis Cartesii, Amsterdam: L. Elsevier, 1653, 12o, 320 pp.17 J.A. van Ruler, The crisis of causality: Voetius and Descartes on God, nature, and changeLeiden/New York, Brill, 1995, p. 23-28.

7figure, and so on, Regius admits one special form, the human soul, which cannot be

explained in terms of the general form:

[The human soul] cannot be reduced to the general or material

form, because it cannot arise out of movement, rest, figure and

the disposition of the parts. For we easily understand how an

ingenious disposition of parts can produce a wonderful machine,

which, in virtue of the movement, situation, figure and size of its

parts, performs certain actions. However, that by the same

principles it could be conscious of its acts and would be able to

think is inconceivable, because all those principles can do is

move it in different ways.18

As the soul (mens) cannot be reduced to, nor explained by, motion, rest, figure and the

disposition of parts, it is a separate principle, as necessary as the material forms to

explain nature. In the Fundamenta physices as well as in the Philosophia naturalis,

Regius subsequently summarizes these principles of new philosophy in the following

verses, easily to be memorized by students:

Mens, mensura, quies, motus, positura, figura,

Sunt cum materi cunctarum exordia rerum.

Mind, measure, rest, motion, position and figure

Are, together with matter, the principles of all things.19

This was the adage of new philosophy according to Regius, which made its

first appearance in print in his disputations of 1641.20 It was immediately attacked by

anti-Cartesians like Maarten Schoock and Jacob Revius, which is presumably the

18 Regius, Fundamenta physices, p. 29; unaltered in Philosophia naturalis, p. 44. Englishtranslation from Th. Verbeek, The invention of nature, in: S. Gaukroger, J. Schuster and J.Sutton (eds.), Descartes Natural Philosophy, London/New York: Routledge, 2000, p. 149167,p. 155, with slight modifications. An earlier form of the argument is found in the 1641disputation De illustribus aliquot qauestionibus physiologicis (disp. III, art. VIII) where it isimmediately followed by the notorious assertion that the human soul is an ens per accidens.19 Regius, Fundamenta physices, p. 29; Philosophia naturalis, p. 45.20 Regius, Physiologia sive cognitio sanitatis (Bos, p. 202).

8reason why the Utrecht professor announced them as my famous verses in 1646.21

As it happens, they became very well known indeed, because they were cited by

Antoine Arnauld and Pierre Nicole in the Logique de Port-Royal, where the verses are

presented as the Cartesian alternative to the Aristotelian predicaments.22 The verses

appear to have been especially popular in France, where they were incorporated in

introductory courses in philosophy from the late 17th century till the second half of the

18th century.23 Obviously they were seen as a Cartesian standard, but were they?

From the argument that the mind cannot be reduced to the general or material

form one may deduce that the human soul is a distinct substance, but the argument is

ambiguous. The possibility that the mind could be a mode of the body is intentionally

left open, and in the Philosophia naturalis Regius adopted this skeptical position. In

the, futile, attempt to conciliate Descartes, Regius had suppressed his own conclusion

in the Fundamenta physices, but in his final letter to the French philosopher he

vigorously defends his view on the human soul. Thanks to Revelation we are,

according to Regius, certain that the rational soul is an immortal substance; however,

this cannot be proven by any natural means, so, on natural grounds, there is nothing

wrong with the statement that the soul can be either a mode of the body or a substance

that is really distinct from the body. Regius claims that he is actually reinforcing the

authority of the Bible, as opposed to those who claim that they can tackle the question

with rational arguments; indeed, given the fact that those arguments are necessarily

weak and defective they actually undermine the authority of Holy Writ. No one,

therefore, can blame him, Regius, for disagreeing with Descartes, given the fact that

his views have no foundation in reason. You, Descartes, Regius continues,

promise in your metaphysics nothing but what can be grasped clearly and evidently,

21 M. Schoock, Admiranda methodus novae philosophiae Renati des Cartes, Utrecht, W. Strick,1643, p. 198 (French translation in Th. Verbeek, La querelle dUtrecht, Paris, Les impressionsnouvelles, 1988, p. 282); J. Revius, Suarez repurgatus, Leiden, F. Heger, 16431644, p. 208.22 A. Arnauld and P. Nicole, La logique ou lart de penser, Paris, C. Savreux, 1662, p. 52.23 The verses prominently figure in an engraving by tienne Gantrel (16461706), depictingthe triumph of Cartesian philosophy, which was apparently widely used at the Frenchcolleges and universities. However, as the Port Royal Logic had omitted the authors name,no one knew that this mnemonic aid was Regius. Eventually, the verses were mistaken forthe very thing they tried to replace. In the early 19th century Joseph de Maistre wrote:Aristote disait, autant quil me souvient aujourdhui 29 juin 1805 de ce que jai appris aucollge en 1765: Mens, mensura, quies, motus, positura, figura, Sunt cum materia cunctarumexordia rerum (Ph. Barthelet, Joseph de Maistre, Lausanne: Lge dhomme, 2005, p. 229). Forfurther details, see E.-J. Bos, Een kleine geschiedenis van een cartesiaans versje, in: M. vanEgmond, B. Jaski and H. Mulder (eds.), Bijzonder onderzoek. Een ontdekkingsreis door deBijzondere Collecties van de Universiteitsbibliotheek Utrecht, Utrecht University Library, 2009, ch.34, p. 244251. URL: http://boek425.library.uu.nl/.

9but the disputes you had with qualified persons have done nothing but to increase

doubt and uncertainty. Your reply is that your arguments are nevertheless clear and

evident, but any lunatic may claim the same for his own fantasies.24

Apparently, in the Fundamenta physices Regius purified his earlier work from

views with no foundation in reason. From the passage cited above it is, first of all,

clear that Descartes criterion of truth is among them. Clearness and distinctness are,

according to Regius, no absolute or intrinsic, but relative properties of ideas. An idea

can be more, or less, clear and distinct than another idea, but is never clear and

distinct in itself. In the epilogue to Philosophia naturalis, Regius summarizes his

method by claiming that he always strives to attain the most probable explanation of

natural phenomena.25 In other words, Regius rejects the concept of an ultimate and

definitive explanation, not only in physics but also in metaphysics.26 However, there

is at least one issue in which it is impossible to arrive at a preliminary judgement. For

on purely natural grounds, as Regius claims in his last letter to Descartes, we cannot

decide on the true nature of the human soul.

The Organic Soul

In order to understand why the question on the nature of the human soul does not

admit a philosophical solution we must return to Regius Explicatio, to the passages

he suppressed from the Fundamenta physices.

In articles 16 to 18 Regius offers an account of the faculties of the soul:

16. The mind has two different sorts of thoughts: intellect and

volition.

17. Intellect comprises perception and judgement.

18. Perception comprises sense-perception, memory and

imagination.27

24 Bos, p. 190 (AT, IV, p. 255). The translation is mine, partly in paraphrase.25 Regius, Physiologia naturalis, p. 441-442.26 Th. Verbeek, The invention of nature, p. 160-161.27 XVI. Cogitatio mentis est duplex: intellectus et voluntas. XVII. Intellectus est perceptio etjudicium. XVIII. Perceptio est sensus, reminiscentia, et imaginatio. AT, VIIIB, p. 345-346;CSMK, p. 296.

10

On several occasions Descartes offers a similar account, but his list has one

additional element that is never absent, namely pure intellect. In the Meditations

Descartes outlines how this particular faculty is capable of correctly judging the real

distinction between body and soul. Contrary to sensation and imagination, pure

intellect does not require the body in any way for its operations. It turns to itself when

it contemplates God, the mind itself, the essences of mind and matter, and the objects

of geometry.28 In Regius Physiologia (1641) we find a more orthodox Cartesian

description of the faculties of the soul. As in the Explicatio, thought is, divided in

understanding and will. Understanding is then divided in perception and judgement.

So far no differences. However, perception is divided again into two categories,

namely organic and inorganic. Organic perception includes sensory perception,

memory and imagination; inorganic perception is the power of the soul to perceive

incorporeal things, like God and the rational soul, without any assistance from the

body.29 Thus, something similar to pure intellect is still present in Regius

Physiologia, namely inorganica perceptio which enables the human mind to perceive

incorporeal entities as God and the human mind itself, unaided by the body.

Does the deletion of this category in the Explicatio point to a sudden change in

opinion? Apparently it does not, because even in the Physiologia that category is

already anomalous, and it seems that it was incorporated only at Descartes insistence.

In the Spring of 1641 Regius sent Descartes the draft of the first disputation in the

series Physiologia. In his reply Descartes writes:

I do not agree with you when you define actions as operations

performed by man by the power of soul and body. For I am one

of those who deny that man understands by means of the body.

Nor am I impressed with the argument you use to prove the

contrary; for even though the mind is hindered by the body,

28 AT, VII, p. 34, 53, 71-73.29 Inorganica perceptio est, qu mens nostra sine organo ullo percipit res imagine corporecarentes, ut Deum, animam rationales, etc., Physiologia III-a/Bos, p. 223, defended in June1641. For a history of the concept of organic soul in Renaissance philosophy, see K. Park,The Organic Soul, in: C. Schmitt and Q. Skinner (eds.), The Cambridge History of RenaissancePhilosophy, Cambridge, Cambridge University Press, 1988, p. 464-484. Regius possible sourcefor the idea of inorganic perception may be Cesare Cremonini (15501631), one of histeachers at Padua. See E. Garin, History of Italian philosophy, Amsterdam, Rodopi, 2008, 2 vols.,vol. 1, p. 377.

11

when it is a matter of understanding immaterial things it cannot

be helped by the body, but only hindered by it.30

Regius adjusted the text of the first disputation after reading Descartes

comments and omitted the argument that the mind would need the body to understand

immaterial things. Moreover, he changed the general definition of actions into

Actions are operations performed by man by the power of the soul, or the body, or

both.31

That adjustment, however, appears to be only cosmetic. Although Regius

amended definition makes it possible for actions to be an operation of the soul alone,

when he actually develops the concept of action in the second disputation of the

Physiologia it turns out to be an empty class.

In the second disputation Regius divides actions into two categories: natural

and animal actions. Natural actions arise and are brought about by the disposition of

the (bodily) parts. He emphasizes the words arise and bring about in order to

distinguish natural actions from animal actions, which, even though they arise from a

bodily disposition, are brought about by the rational soul.32 As thought is an animal

action, it cannot be an operation of the soul alone.

Finally, in the third disputation, where animal actions are discussed, Regius

retains the amended definition of actions, describing inorganic perception as the

power of the soul to perceive, without any assistance from the body, incorporeal

things. Regius thus admitted a kind of animal action that by virtue of the distinction

between natural and animal actions in the second disputation is impossible.

The contradiction arises because, on the one hand, Regius accepts Descartes

correction with respect to the definition of action, but on the other hand persists in his

own view that all thought is an operation of the mind as well as the body. In his

Explicatio Regius resolves the conflicting views by removing the concept of

inorganica perceptio, thereby making it clear that in his view a pure intellect does

not existit is one of Descartes errors alluded to in the final letter to the French

philosopher.

30 Descartes to Regius, [early May 1641], Bos, p. 70-71 (AT, III, p. 374-375); CSMK, p. 183.31 Actions sunt operationes ab homine vi animae humanae, vel corporis, vel utriusquefactae, Physiologia I-b, p. [15]/Bos, p. 209, defended on 5 [/15] May 1641.32 Physiologia II-a, p. [17]/Bos, p. 211; defended in May/June 1641.

12

Would Regius thus subscribe the view that it is impossible to think about

immaterial entities? For that capacity was attributed to inorganic thought. It is in any

case the consequence Descartes drew from Regius theory. In the Notae in

programma quoddam he criticizes Regius classification of the powers of the soul:

in enumerating the forms of perception, he lists only sense-

perception, memory and imagination. We may gather from this

that he does not admit any pure understanding, i.e.

understanding which is not concerned with any corporeal

images, and hence that his view is that we have no knowledge of

God, or of the human mind, or of other incorporeal things. The

only explanation for this that I can think of is that he is never

aware of having a pure thought, a thought which is quite distinct

from any corporeal image.33

The last remark, that Regius apparently never had any pure thought on the

human soul or God, is obviously meant ironically, but Regius may have had little

hesitations to agree. He does not deny the possibility to think about God and the soul,

but he would say that it is impossible without the body: Even when thinking about

immaterial substances we need the body. In response to Descartes criticism in the

Notae, Regius develops the point further in the Philosophia naturalis.

He argues that, even if the human mind is a substance that is really distinct

from the bodya truth of Revelationas long as the mind is in the body, it is in all

its actions organic, that is to say, it needs the bodily, physical organs. Without the

body it cannot bring anything about; the soul needs the brain for all its mental acts,

not only when it turns its attention to corporeal things, but also when it contemplates

mental or divine things. We cannot think about material or immaterial things without

perception and imagination, or without the aid of memories traced in the brain and the

animal spirits.34 Thus, Descartes assumed existence of pure intellect is an

unnecessary multiplication of entities:

33 AT, VIIIB, p. 363-364; CSMK, p. 307.34 Regius, Philosophia naturalis, p. 342-343, 356-357.

13

Since [] we are able to explain all its operations [i.e., those of

the mind] by those faculties of the intellect, which were already

explained, there is no need to add to them a pure intellect or

anything similar as something that is distinct from them.35

According to Regius, the human mind is not able to contemplate itself

purely, that is, without the intervention of the body. As the soul is dependent on the

body in all its operations it cannot rise above matter in this life. The question of the

true nature of the human mind can therefore not be resolved by natural means. Is the

soul, according to Regius, a mode of the body? The Utrecht professor shows that that

would involve no contradiction, but at the same time maintains that philosophy cannot

answer that question. The appeal to Revelation is not a philosophical last resortthe

truth of faith does not contradict natural reason.

Cartesianism without the Meditations

In his last letter to Descartes Regius claims that the French philosopher harmed his

own reputation by publishing the Meditations (1641) and even accuses him of

dissimulation.36 Years before their break, Regius voiced objections against the

Meditations on two occasions. First, after reading the draft of the work in 1640, and

for a second time in 1642, presumably after reading the Objections and Replies.37 On

both occasions Regius challenged Descartes theory of innate ideas, in particular of

the idea of God, and the doctrine of clear and distinct perception, in particular of the

distinction between body and soul. It is a curious twist of fate that is was precisely

Regius whom Descartes chose to be the first reader of the draft of the Meditations, as

it was that work by which he alienated the Utrecht professor from him. What

originally attracted Regius in Descartes new philosophy must have been, next to the

essays La Dioptrique and Les Meteores, chapter 5 of the Discours, in which Descartes

extensively summarizes the contents, scope and aim of Le Monde and LHomme,

35 Regius, Philosophia naturalis, p. 404. The translation is borrowed from D. Clarke, HenricusRegius, The Stanford Encyclopedia of Philosophy (Fall 2008 Edition), Edward N. Zalta (ed.), URL:http://plato.stanford.edu/archives/fall2008/entries/henricus-regius/.36 Bos, p. 189-190 (AT, IV, p. 270). On Regius accusation of dissimulation, see C. Wilson,Descartes and the corporeal mind. Some implications of the Regius affair, in: S. Gaukroger,J. Schuster and J. Sutton (eds.), Descartes Natural Philosophy, p. 659-679, esp. p. 673-677, and F.Hallyn, Descartes. Dissimulation et ironie, p. 143ff.37 See Descartes to Regius, [June 1640], Bos, 51 (AT, III, p. 64-65), and Descartes to Regius,[June 1642], Bos, p. 153-154 (AT, III, p. 566-567).

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finished off with a for Regius the medical doctor very appealing example: a detailed

explanation of the circulation of the blood and the working of the heart. Regius saw

this last subject as exemplary of new science and presented it in his first public

disputation at Utrecht University in 1640.38 The mechanist approach in physiology

and physics promised a natural philosophy with by far more explanatory power than

traditional philosophy, which could also accommodate the quantitative medicine of

Regius teacher at Padua, Santorii.39 Moreover, when Regius actually read Le Monde,

presumably in 1641,40 he may have been strengthened in his view that the soul cannot

operate without the body, a view he probably already subscribed to before he read

Descartes. Finally, Le Monde showed that a Cartesian physics is possible without a

metaphysical foundation.41 In his Fundamenta physices Regius freed Cartesian

natural philosophy from what he saw as metaphysical ballast, and the apparent

easiness by which he accomplished that aim, indicates that the connection between

medicine and physics on the one hand and metaphysics on the other was not so strong

as Descartes assumed. Recently, several authors have, with specific reference to the

DescartesRegius controversy, argued that the relation between the Meditations and

Descartes work on physiology and physics is far from being straightforward or

unproblematic.42 Regius natural philosophy is not a distortion of Descartes

philosophy, but an answer to Descartes dualism that raises problems that are not, or

even cannot, be resolved within the French philosophers own theoretical framework. 38 The disputation Pro sanguinis circulatione was publicly defended on 10/20 June 1640. Thetext of the disputation is published in AT, III, p. 727-734. For further details on thedisputation, see Bos, p. 46-48.39 Santorio Santorii (1561-1636), professor of medicine at Padua, used an analogy that Regiusre-encountered in the Discours (AT, VI, p. 50), namely the comparison of a living organismwith a clock, the movements of which depend on number, form and the disposition of parts.Cf. M.D. Grmek, La premire rvolution biologique. Rflexions sur la physiologie et la mdecine duXVIIe sicle, Paris, Editions Payot, 1990, p. 71-76. For Santoriis influences on Regius, see K.Rothschuh, Henricus Regius und Descartes. Neue Einblicke in die frhe Physiologie (1640-1641) des Regius, Archives Internationales dHistoire des Sciences, 21 (1968), p. 39-66, esp. p. 51-52, and P. Farina, Sulla formazione scientifica di Henricus Regius: Santorio Santorio e ilStatica Medicina, Rivista Critica di Storia della Filosofia, 30 (1975), p. 363-399.40 Bos, p. 67. According to Descartes, Regius got hold of a copy of LHomme, against Descarteswishes, just before the printing of Fundamenta physices was completed (cf. Descartes toMersenne, 23 November 1646, AT, IV, 567). Regius from his side denied that he had ever seenthe manuscript (Bos, p. xviii-xix, 47).41 Th. Verbeek, The invention of nature, p. 162.42 Th. Verbeek, The invention of nature; C. Wilson, Descartes and the corporeal mind. Someimplications of the Regius affair; D. Clarke, The Physics and Metaphysics of the Mind:Descartes and Regius, in J. Cottingham and P. Hacker (eds.), Mind, Method, and Morality.Essays in Honour of Anthony Kenny, Oxford, Oxford University Press, forthcoming. For aninteresting argument to the contrary, see D. Kolesnik-Antoine, Lhomme cartsien. La force qualme de mouvoir le corps: Descartes, Malebranche, Rennes, Presses universitaires de Rennes,2009, p. 64- 75.

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Regius is a Cartesian natural philosopher, for he genuinely thought he saved the

Cartesian program.43

43 An earlier version of this paper was presented at the University of Heidelberg in 2005,during the international conference Philosophische Theorien des Geistes in der frhen Neuzeit,organised by Andreas Kemmerling, Dominik Perler, and Ralph Schumacher. I thankDesmond Clarke and Theo Verbeek for comments on later drafts.