Kenny Anthony. Medieval Philosophy: A New History of Western Philosophy. Volume 2

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The words ‘Wtting and just’ can be understood in two senses. In the Wrst sense

‘Wtting and just’ is taken in primary conjunction with the verb ‘is’, and is thus

restricted in reference to what is the case at present, and is assigned to God’s power

in this restricted sense. So restricted, the proposition is false: for its sense is this:

‘God can only do what is Wtting and just as things are’. But if ‘Wtting and just’ is

taken in primary conjunction with the verb ‘can’, which has an ampliWcatory

force, and only subsequently in conjunction with the verb ‘is’, then the reference

will be to a non-speciWc present, and the proposition will be true, understood

in this sense: ‘God can only do what, if He did it, would be Wtting and just’. (1a

25. 5. 2)

If we prefer the idiom of possible worlds to the idiom of powers, we could

make Aquinas’ point as follows. In every possible world, what God does

is Wtting and just; it does not follow, nor is it true, that whatever God does is

something that is Wtting and just in every possible world.

Could God have made the world better? He could not have made it by

any better method than he did; he made it in the wisest and best possible

way. Could he have made men better? He could not have made human

nature better than it is; creatures better by nature than we are would not

be humans at all. But of any individual human, it is true that God could

have made him better. And given any actual creature, however exalted, it is

within God’s power to make so mething better. There is no such thing as

the best of all possible creatures, let alone the best of all possible worlds.

Aquinas’ Proofs of God’s Existence

In philosophical theology Aquinas is most often remembered not for his

treatment of divine attributes such as omniscience and omnipotence, but

for his endeavour to establish, by purely philosophical methods, the actual

existence of God. Proofs of divine existence are to be met with in many

places in his works: in the De Potentia, for instance, he takes, as the starting

point of his proof, the taste of pepper and ginger. Wherever, he says, causes

whose proper eVects are diverse produce also a common eVect, the

additional common eVect must be produced in virtue of some superior

cause of which it is the proper eVect. For example, pepper and ginger,

besides producing their own proper eVects, have it in common that they

produce heat: they do this in virtue of the causality of Wre, of which heat is

the proper eVect.

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All created causes, while having their own proper eV ects that distinguish them one

from another, also share in a single common eVect which is being. Heat causes

things to be hot, and a builder causes there to be a house. They have in common

therefore that they cause being, and diVer in that Wre causes Wre and a builder causes

a house. There must, therefore, be some superior cause whose proper eVect is being

and in virtue of which everything else causes being. And this cause is God. (DP 7. 2c)

Better known are the Five Ways which are placed near the beginning of

the Summa Theologiae: (1) motion in the world is only explicable if there is a

Wrst motionless mover; (2) the series of eYc ient causes in the world must

lead to an uncaused cause; (3) contingent and corruptible beings must

depend on an independent and incorruptible being; (4) the varying degrees

of reality and goodness in the world must be approximations to a subsistent

maximum of reality and goodness; (5) the ordinary teleology of non-

conscious agents in the universe entails the existence of an intelligent

universal orderer.10

None of the Five Ways is successful as a proof of God’s existence: each

one contains either a fallacy, or a premiss that is false or disputable. The

Wrst way depends on the premiss that whatever is in motion is moved by

something else: a principle universally rejected since Newton. The series

mentioned in the second way is not a series of causes through time (which

Aquinas himself admitted could reach backwards for ever), but a series of

simultaneous causes, like a man moving a stone by moving a crowbar;

there is no reason why the Wrst cause in such a series should be God rather

than an ordinary human being. The third way contains a fallacious

inference from ‘Every thing has some time at which it does not exist’ to

‘There is some time at which nothing exists’. The fourth way depends on a

Platonic, and ultimately incoherent, notion of Being. The Wfth way is much

the most persuasive of the arguments, but its key premiss, ‘Things that lack

awareness do not tend towards a goal unless directed by so mething with

awareness and intelligence, like an arrow by an archer’, needs, since

Darwin, more supporting argument than we are given.

Many attempts have been made, and no doubt will be made, to restate

the Five Ways in a manner that eliminates false premisses and fallacious

reasoning. But one of the most promising recent attempts to reinstate

10 For a detailed treatment of the Five Ways, see my book The Five Ways (London: Routledge,

1969).

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Aquinas’ proofs of God’s existence takes its start not from the Summa

Theologiae but from the Summa contra Gentiles.11

The argument runs thus. Every existing thing has a reason for its

existence, either in the necessity of its own nature, or in the causal eYcacy

of some other beings. We would never, in the case of an ordinary existent,

tolerate a blithe announcement that there was simply no reason for its

existence; and it is irrational to abandon this principle when the existing

thing in question is all-pervasive, like the universe.

Suppose that A is an existing natural thing, a member of a (perhaps

beginningless) series of causes and eVects that in its own nature is disposed

indiVerently to either existence or non-existence. The reason for A’s

existing must be in the causal eYcacy of other beings. However many

beings may be contributing to A’s present existence, they could not be the

reason for it if there were not some Wrst cause at the head of the series—

something such that everything other than it must be traced back to it as

the cause of its being.

Persuasive as it is, this argument contains a key weakness. What is meant

by saying that A is ‘disposed indiVerently to either existence or non-

existence’? If it means ‘disposed indiVerently to going on existing or not’,

then the contingent beings of the everyday world, from which the argu-

ment starts, do not Wt the bill. Contingent things aren’t of their nature

equally disposed to exist or not: on the contrary, most things naturally

tend to remain in existence. On the other hand, if it means ‘disposed

indiVerently to come into existence or not’, then we lapse into absurdity:

before A exists there isn’t any such thing as a non-existing A to have, or to

lack, a tendency to come into existence.

Duns Scotus’ Metaphysical Proof of an InWnite Being

Flaws in Aquinas’ proofs of God’s existence were pointed out very shortly

after his death. Among his critics was Duns Scotus, who oVered his own

proofs in their place. The one closest to the argument of the Summa contra

Gentiles makes use of the concept of causality to prove the existence of a Wrst

cause. Suppose that we have something capable of being brought into

existence. What could bring it into existence? It must be something, because

11 See Norman Kretzmann, The Metaphysics of Creation (Oxford: Clarendon Press, 1999), 84–138.

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nothing cannot cause anything. It must be something other than itself, for

nothing can cause itself. Let us call that something else A. Is A itself caused?

If not, it is a Wrst cause, which is what we were looking for. If it is caused, let

its cause be B. We can repeat the same argument with B. Then either we go

on for ever, which is impossible, or we reach an absolute Wrst cause.

Scotus, like Aquinas, makes a distinction between two kinds of causal

series, one of which he calls ‘essentially ordered’, and the other ‘acciden-

tally ordered’. He does not deny the possibility of an unending regress of

accidentally ordered causes, such as the series of human beings, each

begotten by an earlier human. Such a series is only accidentally ordered.

A father may be the cause of his son, but he is not the cause of his son’s

begetting his grandson. In an essentially ordered series, A not only causes B,

which is the cause of C, but actually causes B to cause C. It is only in the

case of essentially ordered series—e.g. a gardener moving earth by moving

a spade—that an inWnite regress is ruled out. An accidentally ordered series

is, as it were, a horizontal series of causes; an essentially ordered series is a

vertical hierarchy; and Scotus tells us, ‘inWnity is impossible in the

ascending order’ (DPP 4, p. 22).

Even after the two kinds of series have been distinguished, there seem

several weaknesses in Scotus’ argument, considered as a proof of the

existence of God. In the Wrst place, it seems, like the proof of the Summa

contra Gentiles on one interpretation, to assume that it is sensible to talk of

something non-existing as having, or lacking, the power of coming into

existence.12 In the second place, it is not clear why instead of a single inWnite

Wrst cause the argument does not lead to a number of Wnite Wrst causes.

Scotus in fact admits that he has not produced a proof of God; but the

reason he gives is not either of the above. Unlike Aquinas, who took as his

starting point the actual existence of causal sequences in the world, Scotus

began simply with the mere possibility of causation. He did so deliberately,

because he preferred to base his proof not on contingent facts of nature,

but on purely abstract possibilities. If you start from mere physics, he

believed, you will never get beyond the Wnite cosmos.

But the consequence of this is that the argument, up to this point, has

proved only the possibility of a Wrst cause: we still need to prove that it

actually exists. Scotus in fact goes one better and oVers to prove that it must

12 See p. 203 above on objective possibility.

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exist. A Wrst c ause, by deWnition, cannot be brought into existence by

anything else; so either it just exists or it does not. If it does not exist, why

does it not? If its existence is possible at all, there is nothing that could cause

its non-existence. But we have shown that it is possible; therefore it must

exist. Moreover, it must be inWnite; because there cannot be anything that

could limit its power. Scotus accepts that an inWnite being is possible only if

there is no incoherence in the notion of such an entity. It is a weakness, he

thinks, in Anselm’s argument that he does not show that ‘that than which

no greater can be thought’ is a coherent concept. But if there were any

incoherence between the notions of being and inWnity, Scotus claims, it

would long ago have been detected . The ear can quickly detect a discord,

and the intellect even more easily detects incompatibilities (Ord. 4. 162–3).

Even if we concede to Scotus that the notion of God is coherent, his

argument seems to fail, by trading on diVerent senses of ‘possible’: logical

possibility, epistemic possibility, and real possibility. From the mere logical

possibility of God’s existence, nothing follows about whether he actually

exists. An agnostic may admit that perhaps, for all we know, there is a God:

that is what is meant by ‘epistemic possibility’. But from logical possibility

and epistemic possibility, nothing follows about real possibility, still less

about actuality. ‘It is possible that there is a God’ is not the same as ‘It is

possible for God to come into being’.13 Since the concept of godhead

includes everlasting existence, nothing has the power to bring any god

into existence. If God exists, he must always have existed. Nor does

anything have the power to prevent a god from existing, or to terminate

the exist ence of a god. Such powers are all conceptually impossible, because

of the nature of the concept God. But the absence of such powers shows

nothing at all about whether that concept is or is not instantiated.

For Scotus, the most important element in the concept of God is

inWnity. The notion of inWnity is simpler, more basic, than other concepts

such as goodness: it is constitutive of divine being, not just an attribute of

divinity. InWnity is the deWning characteristic of all the divine attributes:

divine goodness is inWnite goodness, divine truth is inWnite truth, and so

on. Each divine perfection ‘has its formal perfection from the inWnity of the

essence as its root and foundation’ (Oxon. 4. 3. 1. 32). Scotus proves the

13 The diVerence between the two statements is much more obvious in English than in the

medieval Latin equivalent.

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existence of God by proving the existe nce of an inWnite Wrst principle; only

after establishing the inWnity of God does he proceed to derive other divine

attributes such as that of uniqueness and simplicity.

Scotus did not believe that all the divine attributes could be proved by

natural reason. Reason could show that God was inWnite, unique, simple,

excellent, and perfect. Reason could not, however, show that God was

omnipotent, because revelation had shown that God had the power to do

things that reason could never have guessed at (e.g. beget a son). Reason

could, however, show that God had the power to create a world out of

nothing, and that in so creating he enjoyed absolute freedom.

The inWnite God, reXecting on his own essence, sees it as capable of being

reproduced or imitated in various possible partial ways: it is this that, before

all creation, produces the essences of things, existing in the form of divine

ideas. This reXection is an exercise of the divine intellect; it is not a free

action of the divine will.

The divine intellect, as, in some way, that is, logically prior to the act of the divine

will, produces those objects in their intelligible being and so in respect of them

it seems to be a merely natural cause, since God is not a free cause in respect

of anything but that which presupposes in some way his will or an act of his will.

(Ord 1. 163)

The essences in the divine mind, as Scotus conceives them, are in them-

selves neither single nor multiple, neither universal nor particular. They

resemble—and not by accident—Avicenna’s horseness, which was not identi-

cal either with any of the many individual horses, nor with the universal

concept of horse in the human mind. By a sovereign and unaccountable act

of will, God decrees that some of these essences should be instantiated; and

thus the world is created. The decree of his will is eternal, unchangeable; but

the execution of the decree takes place in time (Ord. 1. 566). We cannot look

for any reason for God’s creative decree: he does not create for the sake of any

good, since all good in creatures is the consequence of his creation.

Scotus, Ockham, and Valla on Divine Foreknowledge

God’s knowledge of what is possible, as we have seen, precedes the act of

will by which he brings chosen possible entities into existence; but his

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knowledge of what is actual depends solely on his knowledge of his own

will. Scotus rejects Aquinas’ view that God is omniscient because he sees

the whole of time as present to him all at once. Anything that is presen t to

God, Scotus argues, cannot be genuinely past or future; the way things

appear to God is the way they really are. For Scotus, God knows what has

been the case, what is the case, and what will be the case, because he is

aware of his own decree determining what has been, what is, and what will

be. It may well be thought that such an explanation of divine omniscience,

and in particular of divine foreknowledge, leaves no room for the exercise

of human free will. Scotus takes this complaint very seriously, but in the

end rejects it.

Consider, he says, the following argument: ‘God believes I will sit

tomorrow; but I will not sit tomorrow; therefore God is mistaken’. This

argument is clearly valid. We must surely therefore say that the following

variation on the argument is also valid: ‘God believes I will sit tomorrow;

but it is possible that I will not sit tomorrow; therefore God c an be

mistaken’. We are simply employing the schema: If p and q entail r, then

p and possibly q entail possibly r. Since God cannot be mistaken, the argument

seems to show that it is not possible for me to do anything other than what

God has foreseen I will in fact do.

Scotus’ solution to this argument is to deny the validity of the schema

involved. He gives a counter-example, which can be rendered as follows.

Suppose there are two suitcases A and B, each of which I can carry. But

suppose further that I am carrying my suitcase A. In these circumstances,

to carry your suitcase B would be to carry both A and B, which is beyond

my strength. ‘I am carrying A and I am ca rrying B’ obviously entails ‘I am

carrying A and B’. But ‘I am carrying A’ and ‘I can carry B’ do not between

them entail ‘I can carry A and B’ (Lect. 17. 509).

Scotus’ response is eVective, and it is applicable in many contexts other

than the theological one. There are many cases where I can do some action

X but will not. In such cases, there will be descriptions of doing X that will

describe it in terms of the fact that I am not, in fact, going to do X. Thus, let

us suppose that I am going to eat my cake. I can, if I want, have my cake,

but I am not going to have my cake, I am going to eat it. Given the facts of

the case, to have my cake would be to have it and eat it too. But I can, if

I want, have it. So, if the principle is valid, I can have my cake and eat it too.

Scotus’ demolition of the principle in order to show that human freedom

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is compatible with divine decrees provides the essential underpinning for

any form of compatibilism, that is to say, the attempt to show that freedom

and determinism are not the contradictory opposites that they appear at

Wrst sight to be.

Ockham rejected Scotus’ method of reconciling divine foreknowledge

with human freedom, just as Scotus had rejected Aquinas’. God, Scotus

says, foresees future events by being aware of his own intentions, and

future events are contingent, not necessary, because God’s decrees about

the world are themselves contingent. This, Ockham replies, may be suY-

cient to preserve contingency, but it does not suYce to leave the decisions

of creatures free while establishing, at the same time, a basis for foreknow-

ledge of them.14

Ockham’s criticism of Scotus’ position is forceful, but he does not

himself oVer in its place any solution to the problem of divine foreknow-

ledge and human freedom. He makes clear, in fact, that he sympathizes

with the position (which he wrongly attributes to Aristotle) that state-

ments about future contingents lack a truth-value. But unless they are

already true, future contingent propositions cannot be known, even by

God. In spite of this philosophical reasoning, Ockham says, we are obliged

to hold that God evidently knows all future contingents. A treatise exclu-

sively devoted to the problem, Tractatus de Praedestinatione et de Praescientia,

concludes, ‘I say that it is impossible to express clearly the way in which

God knows future contingent events. However, it must be held that he

does know them, but contingently.’15

This was just one instance of the combination of devout Wdeism with

philosophical agnosticism that is characteristic of Ockham’s theology. He is

critical of the arguments for God’s existence to be found in Aquinas and

Scotus. He agree s with Scotus that without a univocal concept of being, it

would be impossible even to conceive of God (III Sent. 9, R); but he agrees

with Aquinas that the primary object of the human mind is not being, but

the nature of material substance (I Sent. 3. 1d).

Philosophical reason cannot prove that God is the Wrst eYcient cause of

everything. There must, indeed, be a Wrst cause, if there is not to be an

inWnite causal regress; but it need not be God, it could be a heavenly body

14 Ockham also rejected Scotus’ non-manifest power. See p. 245 above.

15 Trans. Norman Kretzmann and Marilyn Adams (Chicago: Appleton-Century-Crofts,

1969).

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or some Wnite spirit (Quodl.2,p.1;OTh. 6. 108). But even the impossibility of

an inWnite causal regress is open to question—why should there not be a

series of begotten and begetter stretching forever backwards? Instead of

asking what brings something into existence we might do better to ask

what keeps it in existence; and Ockham agrees that it is implausible to

think that there is an inWnite series of simultaneous entities currently

keeping us in existence. This can be shown, he thinks, not with absolute

certainty, but by arguments that are reasonable enough (I Sent. 2. 10).

This is as far as Ockham is prepared to go in allowing the possibility of a

proof of God’s existence; and even this, he maintains, is insuYcient to

establish that there is only one God. A fortiori we cannot prove by natural

reason that God is inWnite, eternal, omnipotent, and creator of heaven and

earth. With regard to God’s knowledge, we cannot prove philosophically

that God knows actual things other than himself, let alone their future free

actions. All these truths about God have to be accepted as matters of faith.

The reconciliation of freedom and providence was a problem that

occupied humanist thinkers no less than scholastics. Lorenzo Valla, Nich-

olas V’s court philologist, wrote in 1439 a dialogue on free will, critical of

Boethius’ Consolation. It starts from a well-worn problem: ‘If God foresees

that Judas will be a traitor, it is impossible for him not to become a traitor’.

For most of its length the dialogue follows moves and counter-moves

familiar from scholastic discussions: it reads like a child’s version of Scotus.

But, near the end, two surprising moves are made.

First, Valla introduces two pagan gods into the discussion. Apollo

predicted to the Roman king Tarquin that he would suVer exile and

death. In response to Tarquin’s complaints, Apollo said that he wished

his prophecy were happier, but he merely predicted, he did not decide,

Tarquin’s fate. Any recriminations should be addressed to Jupiter. The

introduction of the gods is not just a humanist Xourish: it enables Valla,

without blasphemy, to separate out the two attributes of omniscient

wisdom and irresistible will which, in Christian theology, are inseparable

in the one God.

The second surprise is that when the going gets really tough, Valla takes

refuge in Scripture quotation. He turns to the passage in Paul’s Epistle to

the Romans about the predestination of Jacob and the reprobation of Esau.

‘O the depth of the riches both of the wisdom and knowledge of God! How

unsearchable are his judgements and his ways past Wnding out.’ Rather

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than oVer a philosophical reconciliation between divine providence and

human freedom, Valla ends with a denunciation of the philosophers and

above all of Aristotle. On this crucial topic of natural theology, both

nominalist scholasticism and humanist scholarship reach the same dead

end.

The Informed Ignorance of Nicholas of Cusa

Late medieval thought reaches a climax of agnosticism in Nicholas of

Cusa’s De Docta Ignorantia. No one since Socrates had emphasized so strongly

that wisdom consists in awareness of the limits of one’s knowledge. Brute

ignorance is no virtue: but the process of learning is a gradually increasing

awareness of how much one does not know. Truth is real enough: but we

humans can only approach it asymptotically.

Truth does not admit of more or less, but stands absolute. Nothing other than

truth itself can measure it with accuracy, just as a non-circle cannot measure a

circle in its absolute being. Our intellect, which is not truth, can never compre-

hend truth so accurately that there does not remain the possibility of inWnitely

more accurate comprehension. Our intellect is related to the truth in the way that

a polygon is to a circle: the more angles it contains, the more like a circle it is, but

it never equates to the circle even if its angles are multiplied to inWnity. (DDI 9)

What is true of the intellect’s approach to truth in general is a fortiori true

of its approach to the truth about God.

Cusa’s paradigm of rational inquiry is measurement: we approach the

unknown by measuring it against what we already know. But we cannot

hope to measure the inWnite, because there is no proportion between what

is inWnite and any Wnite thing. Every attempt we make to learn more

about God reveals a new inWnite gap between what we think and what God

really is.

Our reason, guided by the principle of non-contradiction, proceeds by

making distinctions. We distinguish, for instance, between great and small.

But these distinctions are useless in inquiry about God. We may think, for

instance, that God is the greatest of all things, the maximum. Certainly,

God is something than which nothing can be greater. But God, who has no

size at all, is also something than which nothing can be lesser. He is the

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