Mark A. Kulstad

Over the past decades there has been an accumulation of a fine body of

scholarly work indicating that by as early as 1675-1676, the years of writing

of the collection of essays now generally referred to as the De Summa Re-

Leibniz was in possession of many or even most of the central doc-

trines of his later philosophy. One scholar has gone so far as to say that “all

the principle themes” of Leibniz’s later philosophy were already in place by

the end of 1676.1 Among those who have contributed much to our under-

standing in this regard are Georges Friedmann, G. H. R. Parkinson, Chris-

tia Mercer and Konrad Moll.2 Here are some samples of statements by

such scholars about Leibniz at the time of the De Summa Rerum :

The works presented [in the De Summa Rerum] are of great impor-

tance to the student of Leibniz’s philosophy. In effect, they constitute a se-

ries of sketches of a metaphysical system - a system, far from immature,

which contains many of the doctrines for which Leibniz is best known. ...

[I]n the De Summa Rerum we find Leibniz’s first major attempt at present-

ing his philosophy in a systematic form. 3

[A]s his stay in Paris comes to an end [in October, 1676], he [Leibniz]

...has already conceived and conjoined, in a first sketch of his system, all

the principal themes of his own doctrine. 4


For decades, core features of the philosophy of the Discourse on Meta-

have baffled scholars. Despite extensive analysis and study, its deep

motivations and the precise relations among some of its central doctrines

have remained largely mysterious. We will argue in this section that most of

the fundamental tenets of Leibniz’s mature thought are already in place in

1676 and that they grew naturally out of Leibniz’s early metaphysics. 5

While there is no denying the importance of the work of these scholars,

there is some danger that such statements may have an unfortunate side-ef-

fect. They may conceivably lead to scholars overlooking or discounting

some radical differences, on central points, between many of the essays of

the De Summa Rerum and Leibniz’s later, more familiar philosophy. This in

turn could contribute to the missing of what I believe may be a dramatic

moment in Leibniz’s philosophical development, a moment when although

much of his philosophical future was opening itself up to him, much that

was radically inconsistent with that future was vividly alive in his mind as


I emphasize this last point since I think there may arise the easy as-

sumption that, since, as we are granting, many of the main themes of Leib-

niz’s later philosophy were already in his possession at the time of the De

Summa Rerum (1675-1676), the central battles within Leibniz’s mind with

regard to which philosophical path to choose for himself were already

largely over also.6 Indeed, we find the suggestion of precisely this kind of

assumption in the works of at least some of those, considered above, who

have contributed so much to our understanding of this period.

For instance, Friedmann says, immediately after the statement quoted

above, and with special reference to Spinoza, that, “therefore, one can say

that Leibniz discovered his master thoughts before the influence of Spinoza

was able to exercise itself upon him”.7 The suggestion is that once Leibniz


had come upon the ideas that turned out to be his “master thoughts”, there

was little or no possibility that he would be diverted from a path dominated

by these. Now we will grant that Leibniz had discovered some of the

thoughts that turned out to be the master thoughts of his later philosophy;

what we are questioning is that these had already taken on the role of mas-

ter thoughts at the time of the De Summa Rerum , that is, ideas powerful

enough in Leibniz’s mind to rule out the development by Leibniz of any

thoughts inconsistent with them. Our countersuggestion is that these

thoughts were only some among the larger set of seriously competing

thoughts in Leibniz’s mind at this critical juncture in his development.

One of Parkinson’s statements seems also to assume more from the

presence of certain later doctrines in the writings of this period than might

be warranted. He says, “The Paris writings do not present a ‘secret philoso-

phy’ of a Spinozist kind, opposed to what some might call the ‘official phi-

losophy’ of such works as the Theodicy ; on the contrary, they present that

philosophy in an undeveloped, but still clearly recognisable form”.8 Let me

put the point here another way: one assumption, reasonable enough in con-

nection with a single work prepared for publication, is that if the Paris writ-

ings present the philosophy of the Theodicy in recognizable form, then they

do not also present philosophical ideas opposed to this philosophy. But on

the view that the De Summa Rerum papers are separate essays, exploratory,

not prepared for publication and often containing competing lines of

thought, this assumption becomes much less obvious. We would need to

look to the totality of the texts themselves to settle questions about what is

not present in the De Summa Rerum , without simply drawing conclusions

about the collection on the basis of finding in some of them clear evidence

for a certain key set of views.9

What I would like to offer in this paper, then, is a sampling of evidence

that a radical Leibniz also existed in about 1676, a Leibniz who, I submit,

must be understood if we are to claim to understand the philosophical de-


velopment of this European genius of the late seventeenth and early eigh-

teenth century. It is a sampling of evidence that may help to make compre-

hensible Tschirnhaus’s message to a key member of Spinoza’s circle, late in

1675, that he had found Leibniz, “free from the usual prejudices of theolo-

gy”.10 Many readers of such later works as the Theodicy have viewed Leib-

niz in a rather different light, as a philosopher who in fact put rather too

much emphasis on received theological views. If Leibniz were capable of

much more radical views as a young man than as a philosopher in the final

decade of his life, Tschirnhaus’s statement would not be so surprising.

To put the issue another way: if it is true that there are radically com-

peting philosophical visions alive in Leibniz’s mind at the time of the De

Summa Rerum, then the explanation of how Leibniz dealt philosophically

with this intellectual cauldron of differing philosophical tendencies would

be one of the most interesting tasks involved in the matter of gaining a

deeper understanding of the development of the philosophy of Leibniz. Al-

though that is not a project that will be attempted in this paper, the prior

project of documenting the existence of radical suggestions in the De

Summa Rerum
will be.

Before beginning the examination of the radical suggestions, a few

words of clarification about the nature of this project are in order. First,

given my attempts to be brief and to adapt one part of the present project11

to the themes of this conference on unity and multiplicity, I will emphasize

only one main radical suggestion (mentioning two others merely in passing),

the one with the most interesting connections to harmony, unity and multi-


Secondly, having used the word ‘radical’ in my title, I need to say a bit

more about how I am using this term here. My usage, while based on typi-

cal notions, goes a bit beyond them. I put primary emphasis on two criteria

in calling a suggested view of Leibniz’s radical. One that the view in ques-

tion should clash markedly with received opinions (sententiis receptis

, to borrow a phrase from Leibniz which we shall encounter in a

moment) of Leibniz’s age. The other is that the view should be one which


clashes markedly with views taken to be characteristic of Leibniz’s writings

from the Discour on Metaphysics onward.

Finally, although most but not all of the radical ideas I shall treat in

these pages have some relation to Spinoza, I shall not make too much of

this point, mostly simply because of space. To treat with any care the ques-

tion to what extent the radical views I find suggested in the De Summa Re-

rum are related to similar-sounding views in the philosophy of Spinoza - let

alone the question whether Leibniz might have been influenced by Spinoza

in these suggestions - would be impossible in the confines of the present


In an essay of the De Summa Rerum of late 1676 (tentatively dated in

November of that year), Leibniz wrote the following:

A metaphysics should be written with accurate definitions and demon-

strations, but nothing should be demonstrated in it apart from that which

does not clash too much with received opinions. For in that way this meta-

physics can be accepted; and once it has been approved then, if people ex-

amine it more deeply later, they themselves will draw the necessary conse-

quences. 12

Some might see in this passage, even taken without any addition, the

suggestion of someone with ideas clashing with received opinions. But it is

not this passage itself, but this passage taken with the addition of its con-

text that I want to use as the first sample of radical strains in the De Summa

: for Leibniz has just presented a striking one-paragraph argument

for monistic pantheism, beginning with the statement, “It can easily be

demonstrated that all things are distinguished, not as substances (i.e., radi-

cally) but as modes”, and concluding, “Therefore the essence of all things is

the same, and things differ only modally. ... [I]t follows that no thing really

differs from another, but that all things are one”.13 His demonstration turns

on, among other things, definitions of real or radical distinction, essence,

and requisites. The suggestion of the argument, together with the passage

quoted above on the appropriate way to write metaphysics, is that if Leib-

niz were writing his metaphysics for public consumption, instead of for his

private notes of late 1676, he might provide the definitions of the terms just

mentioned, and perhaps some demonstrations based on them, but he would

not himself draw out the radical monistic conclusion of the private notes. In

short, monistic pantheism is the first radical suggestion that we present in


this paper. And Leibniz’s statement on definition and demonstration is evi-

dence that he saw it as radical according to the first criterion set out above.

(Given that monistic pantheism is not a view characteristic of the later

Leibniz, the second criterion is obviously met also).

Since I have treated the theme of Leibniz’s monistic tendencies in this

period on another occasion,14 and since Robert M. Adams’ recent book,

published shortly thereafter, has confirmed and greatly developed the dis-

cussion of that theme,15I shall not simply repeat what has already been said.

Rather, I shall limit myself to mentioning this strong suggestion, or perhaps

simply statement, of monistic pantheism as our first example of radical ten-

dencies in the De Summa Rerum. 16

For the purposes of the present short paper, the other two suggestions

of radical views will be mentioned only briefly, since it is this first example

that has the greatest relevance for the theme of unity and multiplicity.

Among the other radical positions suggested in the De Summa Rerum are,

first, necessitarianism and, secondly, the idea that one of the attributes of

God is the attribute of extension. Neither of these, of course, is taken as a

part of the views of the mature Leibniz. But each of these strikingly uncon-

ventional views seems present in at least some of the papers of the De

Summa Rerum.

We turn then to the pantheistic strain in the young Leibniz in its possi-

ble relation to unity and multiplicity. Although both Adams and I have

highlighted the passage quoted above as perhaps the single clearest state-


ment of Leibniz’s Paris years indicating at least a monistic pantheistic mo-

ment in Leibniz’s development, there are also other passages - perhaps less

decisive taken individually - that are, in my view, of most interest in con-

nection with the issue of unity and multiplicity. They are more clearly con-

nected with pantheism in its more etymological meaning, that of God being

all things, than they are with Spinoza’s monistic pantheistic thesis that there

is but one substance of which all finite things are modes. Here is a listing of

some such statements, all ascribed to the period of 1675 to 1676:

  • Deo, qui est omnia... Deus Unus. 17 (A vi III 512)
  • Tertius infiniti, isque summus gradus est ipsum, omnia , quale infinitum

    est in Deo, is enim est unus omnia. 18 (A vi III 385)
  • omnia est unum. 19 (A vi III 573)
  • omnia unum esse, omnia in Deo esse, quemadmodum effectus in causa

    sua piena continetur, et proprietas alicujus subjecti in ejusdem subjecti

    essentia. (GP I 129, n. 2) 20
  • Deum de Deo. Totum infinitum esse unum. 21 (A vi III 474)
  • There is much to be said about all of these: about their contexts, their

    exact dates, their precise interpretation, and the extent to which Leibniz

    can be said to have fully endorsed them at the time he wrote them. But

    given the present limitations, I can do no more than sketch out, in broad

    strokes, a single line of thought that might be based on these intriguing

    lines, without, unfortunately, full elaboration or defense. We can focus on


    the statement of A vi III 385, that God is one and all, as the most compre-

    hensive of these statements. It brings together all three of the criticai ele-

    ments, God, one, and all, that are discussed in these passages. The passage,

    as I read it, says that God is one, yet God is all. God is, to follow the Latin

    perhaps too closely, the One-All. He is both a unity and a multiplicity, a

    multiplicity encompassing absolutely all things. Both the etymological sense

    of pantheism (not, to be sure, developed in any detail) and the relation to

    the major theme of unity and multiplicity are clearly on display here.

    It cannot have been far from Leibniz’s thoughts, filled from an early

    stage with the idea of Harmony (as Friedmann,22 Mugnai,23 and Mon-

    dadori24 have pointed out), that such theological thoughts provide the

    groundwork for a truly majestic harmony, one perhaps more majestic than

    anything to be found in the writings of the mature Leibniz, despite his rep-

    utation for harmonious constructions. The groundwork would be laid, in

    the mid-1670’s, for the conception that God and all things together consti-

    tute a single Harmony: God, being the one which is all things, would him-

    self be the Harmony of all things. For, according to Leibniz in roughly the

    same time period, “Harmonia ... est unitas in multitudine”, (Harmony is

    unity in multiplicity) (GP I 232) or “harmoniam diversitatem identitate

    compensatam”. (Harmony is diversity compensated by identity) (GP I 73)

    God, we may assume, was always for Leibniz a unity. If God is also all

    things, or, if one prefers, the “multitude” or multiplicity of all things, then

    the multitude is unified, or there is unity in this multitude, and a universal

    harmony, by Leibniz’s own definition, would reign. (Note that this would

    not be a harmony of merely finite things, a harmony of the universe of finite

    creatures, separate from God; this harmony would be the harmony of all

    things, an absolutely universal harmony). To approach this idea from the

    direction of Leibniz’s second definition of harmony, that of diversity com-

    pensated by identity, we would be presented with the diversity of Omnia ,

    or all things, being compensated by the identity or oneness, or unity of

    God, the “unus omnia”, the one and all. So there would be a harmony in

    the cosmos, and this harmony would be the all-inclusive harmony of God.

    But we do not need to proceed so speculatively here. Leibniz himself

    brought together the ideas of God and the harmony of all things. In the


    Confessio philosophi of the early Paris period, he speaks of the “harmonia

    rerum, sive Existentia Dei” (A vi III 128). And only a bit before, towards

    the end of 1671, he had written to Duke Johann Friedrich about the “Har-

    monia universalis, id est DEUS” (Aii I 162). These words are given a con-

    crete sense in conjunction with the pantheistic statements of the latter years

    of the same Paris period that gave rise to the Confessio philosophi.

    Perhaps we can think of this pantheistic harmony as at one extreme of

    the spectrum of theological views which may have had an attraction for

    Leibniz at one time or another as a systematic thinker. It would provide, in

    one sense at least, a most comprehensive solution to one of the major philo-

    sophical versions of the problem of unity and multiplicity, while providing

    an especially prominent position for one of his most cherished philosophi-

    cal ideas, the idea of harmony. But it is, for all its comprehensiveness, a

    dangerous and radical philosophical solution, one that will find little if any

    expression in Leibniz’s mature philosophy. To be sure, some might even

    question whether the position truly finds expression in Leibniz’s philosoph-

    ical writings of the 1670’s. It has not been my purpose here to demonstrate

    this, only to suggest it and to lay out in broad strokes what the position

    might amount to. Be that as it may, the radical position here outlined, in-

    cluding both pantheism and an associated interpretation of universal har-

    mony, warrants the attention of any student of Leibniz, if only because it al-

    lows one to pose more clearly the following question about unity, multiplic-

    ity, God and harmony: what, exactly, is the unity in multiplicity, and the

    identity compensating diversity, in the universal harmony of Leibniz’s ma-

    ture years, where God and the world are said to be distinct, not identical,

    and the world is only an aggregate, not a unity, of finite substances?

    Georges Friedmann, Leibniz et Spinoza , rev. ed., Paris, 1962, p. 105. (When not otherwise

    noted, translations in this paper are my own.)
    Konrad Moll, Der junge Leibniz , 3 vols., Stuttgart-Bad Cannstatt: Frommann-Holzboog,

    1978-1996. (For references to works of the other scholars, v. below.)
    G. H. R. Parkinson, “Introduction”, G. W. Leibniz. De Summa Rerum. Metaphysical Pa-

    pers, 1675-1676
    , translated with an Introduction and Notes by G. H. R. Parkinson, New Haven

    and London, 1992, p. xii (here in after abbreviated as P, followed by the relevant page number).
    Friedmann, Leibniz et Spinoza, p. 105. Friedmann seems to believe that the “first

    major attempt” comes even before 1675. That would not contradict the main hypothesis that we

    are working with here, namely, that by as early as 1675-76 many of the main doctrines of Leibniz’s

    later philosophy were already in place.
    Christia Mercer and R. C. Sleigh, Jr., “Metaphysics: The early period to the Discourse on

    ’, in The Cambridge Companion to Leibniz , ed. by Nicholas Jolley, p. 84. (Mercer

    alone is credited above with this statement, which begins section 3 of the Mercer and Sleigh arti-

    cle, in accordance with the two authors’ note that “Mercer is the author of sections 1-3; Sleigh of

    section 4”. [See n. 1 to p. 67]).
    For many, including Parkinson on the one hand (P, p. LII) and Mercer and Sleigh on the

    other (“Metaphysics: The early period”, op. cit., p. 107), the complete concept theory of substance

    constitutes an important exception to the general principle that Leibniz’s important metaphysical

    principles were in place by 1676. I do not mean to minimize this point.
    Leibniz et Spinoza, op. cit., p. 105. Friedmann contends that Leibniz knew Spinoza’s philo-

    sophy only “very superficially” before leaving Paris ibid.).
    “Leibniz’s Paris Writings in Relation to Spinoza”, Studia Leibnitiana Supplementa , v. 18, t.

    2, p. 89.
    Parkinson, to his credit, in fact repeatedly discusses passages more or less opposed to

    parts of the overall interpretation he presents of the De Summa Rerum, that is, he does look to the

    totality of the texts themselves, as well as presenting his more generai conclusions. Although I dis-

    agree with some of the conclusions he reaches on the basis of this sort of textual work (see, for

    example, my “Did Leibniz Incline towards Monistic Pantheism in 1676?” Leibniz und Europa: VI.

    Internationaler Leibniz-Kongress,
    part I, Hanover, 1994, p. 424-428), I agree entirely with this more

    thorough textual approach. My reason for focusing on the statement of his at the beginning of this

    paragraph is that I am concerned that others will be too ready to take those words as licensing a

    disregard for the genuinely radical philosophical suggestions of the De Summa Rerum, without re-

    membering the qualifications implicit in Parkinson’s more thorough textual approach.
    Spinoza Opera , II 235, ed. C. Gebhardt, Heidelberg, 1925; letter from G. Schuller to

    Spinoza, November 14, 1675, quoted in the translated form given above by C. Wilson, Leibniz's

    Metaphysics: A Historical and Comparative Study,
    Princeton, 1989, p. 116. Schuller was apparently

    transmitting what Tschirnhaus had conveyed to him.
    A fuller version of the project is presented - although without the connection to unity and

    multiplicity, and without the emphasis on the “all is one” formulations to be found in Leibniz in

    this period - in my “Roads Not Taken: Radical Suggestions of Leibniz’s De Summa Rerum” , in G.

    W. Leibniz: Perspectives and Actuality,
    edited by Concha Roldán, a special issue of the journal,

    Synthesis Philosophica , vol. 12, fase. 2, 1977, pp. 403-413.
    A vi III 573; P, pp. 95.
    A vi III 573; P, pp. 93-95.
    “Did Leibniz Incline towards Monistic Pantheism in 1676?” Leibniz und Europa: VI. In-

    ternationaler Leibniz-Kongress, part I, Hanover, 1994, p. 424 ff.
    See Leibniz: Determinist , Theist, Idealist , Oxford, 1994, esp. the section entitled, “Is Leib-

    niz’s Conception of God Spinozistic?”, pp. 123-134.
    To fill in the scholarly context a bit on this question, it appears that those most prominent

    in the long-standing debate about whether Leibniz ever followed Spinoza in pantheism (monism

    of a Spinozistic sort is typically taken as a form of pantheism) have not specially discussed the pas-

    sage stressed by Adams and myself. Some, most notably Ludwig Stein, have, however, held that

    Leibniz did adopt a pantheistic position around 1676 (v. Leibniz und Spinoza , Berlin, 1890, p. 51,

    citing GP I 129, n. 2). Others have disputed this claim. Georges Friedmann’s work, Leibniz et Spi-

    noza', rev. ed., Paris, 1962, is best known. G. H. R. Parkinson’s insightful article, “Leibniz’s Paris

    Writings in Relation to Spinoza” ( Studia Leibnitiana, Supplementa , v. 18, t. 2, pp. 73-89), is more

    recent, qualifying Friedmann’s claims that Leibniz knew relatively little about Spinoza’s philoso-

    phy in Paris (pp. 79-83) and treating with care some pantheistic-sounding passages (pp. 88-89),

    but coming to the conclusion nonetheless that Leibniz was “opposed to pantheism” (p. 89) in the

    Paris writings. Werner Schneiders’ work should also be mentioned, “Deus Subjectum: Zur Ent-

    wicklung der Leibnizschen Metaphysik”, Studia Leibnitiana, Supplementa , v. 18, t. 2, pp. 21-31. It

    is especially good on connecting the sometimes pantheistic-sounding ideas of the Paris years with

    Leibniz’s concept of harmony, arising out of the pre-Paris period. But he resists the idea that

    Leibniz ever gave up the idea of a “supramundane” God, a God distinct from the world (v. esp.

    pp. 28-31).
    “God, who is all things. ...God [is] One”. Parkinson has “there is one God” for the se-

    cond part of this citation. He gives the first part just as it is given here (P, p. 67).
    “The third grade of infinity, and this is the highest grade itself, is all things , which type of

    infinity is in God, for he is one [and] all”.
    “All things are one” (P, p. 95).
    “All things are one, all things are in God, just as an effect is contained in its full cause,

    and also a property of any subject is contained in the essence of the same subject”. This is part of

    an annotation made by Leibniz on the text of a letter from Spinoza to Oldenburg, one of three

    such letters Leibniz annotated. Gerhardt says that Schuller, who oversaw Spinoza’s correspon-

    dence, or perhaps Spinoza himself, gave Leibniz the relevant material. He also indicates that Leib-

    niz’s annotations were made in Amsterdam, in November of 1676 (GP I 118).
    “God is derived from God. The infinite whole is one” (P, p. 25). In section 195 of the

    Theodicy, Leibniz says that an accumulation of an infinite number of substances is not a whole

    (GP VI 232). So the mature Leibniz presumably would not say that all substances (including

    God) constitute a whole that is one. (I am indebted to Laurence Carlin of Rice University for this

    reference.) One thinks here also of Spinoza’s natura naturans and natura naturata : conceivably

    when Leibniz says in his Paris years that God is derived from God he is thinking of God as one

    giving rise to God as the infinite whole, all things, the third sense of infinity (A vi III 385). So one

    might say that God as the ultimate reason of things, the ultimate cause, is one, and God as deri-

    ved from God, as natura naturata , is multiple, and is all things constituting an infinite whole.
    Friedmann, Leibniz et Spinoza , op. cit., pp. 50-51.
    Massimo Mugnai, “Der Begriff der Harmonie als metaphysische Grundlage der Logik

    und Kombinatorik bie Johann Heinrich Bisterfeld und Leibniz”, Studia Leibnitiana, v. 5 (1973)

    pp. 43-73.
    Fabrizio Mondadori, “A Harmony of One’s Own and Universal Harmony in Leibniz’s

    Paris Writings”, Studia Leibnitiana, Supplementa , v. 18, t. 2, pp. 151-168.

    Mark A. Kulstad . :

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