Kenny Anthony. Ancient Philosophy: A New History of Western Philosophy Volume 1

Подождите немного. Документ загружается.

faster and slower. For as a proof of the universality of time he oVers the fact

that any change whatever can be measured in terms of velocity (Ph. 4. 13.

222b30).

What is the relationship between time as it appears in Aristotle’s deWni-

tion (the earlier–later series) and time as expressed by tense (past, present,

and future)? Aristotle links the two by his concept of ‘the now’ (to nun).

We say ‘earlier’ and ‘later’ with reference to distance from the now; and the now is

the boundary between the past and the future . . . But ‘earlier’ is used in opposite

ways in respect to past time and future time: in the past we call earlier that which

is further from the now, and later that which is nearer to the now; in the future

we call earlier that which is nearer to the now, and later that which is further

away. (Ph. 4. 14. 223a5–14)

Aristotle frequently talks of the ‘now’. He seems to use it for two diVerent

purposes: one, the most natural usage, to indicate present time; another,

more technical one, in which it seems to mean ‘instant’ or ‘moment’. In

this second use one can speak of earlier and later nows (Ph. 4. 10. 218b 24; 11.

220a21). In the passage just quoted he appears to be amalgamating the two

uses, to mean ‘the present instant’. This is unfortunate, because the present

instant is an incoherent notion. ‘Present’ is an adjective applicable only to

periods, such as the present year or the present century. Instants are the

boundaries of periods, and future periods are bounded by future instants,

and past intervals by past instants. But present periods are bounded not by

present instants, but by two instants, one of which is past and the other

future. There is no instantaneous present.3

The thesis that the present is an instant sorts ill with another thesis to

which Aristotle attaches considerable importance, namely his claim that

there can be no motion at an instant. If now is an instant, and there is no

motion at an instant, then nothing is in motion now. This argument can

be repeated at any time whatever; so it seems that motion must be forever

unreal. But what, in any case, are we to make of this second thesis in its

own right?

We can readily agree that no obj ect can move at an instant. There

cannot be movement between t and t, any more than there can be

3 G. E. L. Owen (‘Aristotle on Time’, in J. Barnes, M. SchoWeld, and R. Sorabji (eds.), Articles on

Aristotle, iii: Metaphysics (London: Duckworth, 1975), 151) suggests that the confusion here

originates in Plato’s Parmenides 152a–e and is not dispelled until Chrysippus.

188

PHYSICS

movement from A to A. But it does not follow from that that no object

can be moving at an instant, any more than that no object can be moving at a

point. Aristotle, however, is not just making a fallacious inference from

one acceptation of the Greek present tense to another; as we have seen, he

is well capable of steering his way through any possible semantic confusion

of this kind. He oVers an argument for the stronger conclusion, based on

the premiss we have already seen: that whatever is moving has already been

moving. But the correct conclusion to draw from this argument is not that

nothing can be moving at a moment, but that nothing can be moving for a

single moment only.

The truth that lies behind Aristotle’s claim is that we can only talk of X

moving at time t if t is a moment within a period of time, t

to t

, during

which X is in movement; just as we can only talk of X moving at point p if p

is a point on a track between p

and p

along which X is in movement. The

notion of velocity at a point is then a derivative (which may be simple or

complex, depending on the movement’s uniformity or lack of it) from the

length of time, t

to t

, that X takes to get from p

to p

Aristotle on Causation and Cha nge

In his philosophical lexicon in Metaphysics D, and also in Physics 2. 3

(194b16–195b30), Aristotle distinguishes four types of cause, or explanation.

First, he says, there is that of which and out of which a thing is made, such

as the bronze of a statue and the letters of a syllable. This is called the

material cause. Secondly, he says, there is the form and pattern of a thing,

which may be expressed in its deWnition: his example is that the proportion

of the length of two strings in a lyre is the cause of one note being an octave

away from the other. The third type of cause is the origin of a change or

state of rest in something; Aristotle’s followers often called it the ‘eYcient

cause’. Aristotle gives as examples a person reaching a decision, a father

who begets a child, a sculptor carving a statue, a doctor healing a patient,

and in general anyone who makes a thing or changes a thing. The fourth

and last type of cause is the end or goal, that for the sake of which

something is done; it is the type of explanation we give if someone asks

us why we are taking a walk, and we reply ‘In order to keep healthy’. This

last kind of cause became known as the ‘Wnal cause’.

189

PHYSICS

In modern philosophy causation is standardly thought of as a relation

between two events, one being cause and the other eVect. Clearly, Aristotle

structures causation rather diVerently. He does occasionally speak of events

causing events (the Athenian expedition to Sardis caused the war with

Persia; APo. 2. 11. 94a36), but none of the causes he mentions in his

canonical list are episodic events. Most are substantial entities, human

beings, for instance, or chunks of bronze; some are enduring states, such

as the proportion between the strings of the lyre, or the skill of the sculptor

(which is the more immediate cause of the statue; Ph.2.3.195a6). EVects,

too, as he describes them, may be in many categories: states, actions, and

products. The eVects of the third type of cause, eYcient causes, as stated

include substances (a child), artefacts (a statue), and events (the healing of

a patient). But it would not do violence to Aristotle’s concept to say that, in

the case of eYcient causation, what is brought about is always an event,

either a change in something (the recovery of the patient) or the com ing

into being of something (the procreation of the child, the fabrication of the

statue).

The diVerence between Aristotelian and modern notions of cause is so

notable that some scholars reject the traditional translation of aitia as cause;

they prefer other terms such as ‘explanation’, or speak of the four becauses

rather than the four causes. Aristotle himself tells us that they are four

types of answer to the question ‘why?’

The ultimate answer to a ‘why’ may take us, in the case of unchanging things like

mathematics, to the ‘what’ (to the deWnition of straight, or commensurable, or the

like); or it may take us to the originating change (why did they go to war? because

there had been a raid), or to the purpose (so as to come into power) or, in the case

of things that come into being, to the matter. (Ph.2.7.198a14–21)

Here we meet the same four items, but in the order: formal, eYcient, Wnal,

material.

When listing his four causes, Aristotle gives mathematical examples of

formal causes. But the forms whose causation interests him most are the

forms or natures of living beings: it is these that provide the internal

explanation for the life-cycles and characteristic activities of plants and

animals. In these cases, formal and Wnal causes coincide: the mature

realization of natural form being the end to which the activities of the

organism tend. But he was also interested in the explanation of inter-

190

PHYSICS

changes between non-living substances, of which he would give as an

example the turning of water into steam. In such cases he uses the formal

and material causes as expl anatory principles.

Change, for Aristotle, could take place in many diVerent categories:

growth, for instance, was change in the category of quantity, and a change

in a quality (e.g. of colour) was called an alteration (GC 1. 5. 320a13). Local

motion, as we have seen, is change in the category of place. But change in

the category of substance, where there is a change from one kind of thing

into another, was a very special kind of change. When a substance under-

goes a change of quantity or quality, the same substance remains through-

out, with its substantial form. But if one kind of thing turns into another,

does anything remain throughout? Aristotle answers: matter.

We have a case of alteration when the subject of change is perceptible and persists,

and merely changes its properties . . . A body, for instance, while remaining the

same body, is now healthy and now ill; some bronze may be now circular and now

angular, and yet the same bronze. But when nothing perceptible persists in its

identity as a subject of change, and the thing changes as a whole (when e.g. semen

becomes blood, or water changes into air, or air totally into water), such an

occurrence is a case of one substance coming to be and another substance ceasing

to be . . . Matter, in the most proper sense of the term, is to be identiWed with the

underlying subject which is receptive of coming-to-be and passing away. (GC 1. 4.

319b8–320a2)

What is the nature of this matter that underlies substantial change?

Aristotle constantly explains the relationship of matter to form in living

things (e.g. in the formation of a foetus, as he archaically described it above)

by analogy with artefacts. ‘As the bronze is to the statue, the wood is to the

bed, or the formless before receiving form is to the formed object, so is the

underlying nature to the substance’ (Ph.1.7.191a9–12). The analogy is not

easy to grasp. What is the underlying nature that remains through sub-

stantial change in the way in which wood remains wood before and after

being made into a bed? Surely the reshaping of wood or bronze is an

example of an accidental, not a substantial change.

Things do not yet get any clearer when Aristotle tells us,

By matter I mean what in itself is neither of any kind nor of any size nor

describable by any of the categories of being. For it is something of which all

these things are predicated, and therefore its essence is diVerent from that of all

the predicates. All the other categories are predicated of substance, but substance

191

PHYSICS

of matter. Therefore the ultimate subject is of itself neither of any kind or any size

nor anything else. (Metaph. F 3. 1029a21–5)

An entity that is not of any kind or any size or any shape, and of which

nothing at all can be said, appears to be highly mysterious. But that is not

what Aristotle is inviting us to accept. His ultimate matter (he sometimes

calls it prime matter) is not in and of itself of any kind. It is not in and of itself

any particular size, because it can grow or shrink; it is not in and of itself

water, and it is not in and of itself steam, because it is each of these in turn.

This does not mean that there is any time at which it is not of any size, or

any time in which it is neither water nor steam nor anything else.

How then is a chunk of matter to be identiWed? Well, in everyday life we

are familiar with the idea that one and the same parcel of stuV may be Wrst

one kind of thing, and then another kind of thing. A bottle containing a

pint of cream may be found, after shaking, to contain not cream but

butter. The stuV that comes out of the bottle is the same stuV as the stuV

that went into the bottle: nothing has been added to it and nothing has

been taken from it. But what comes out is diVerent in kind from what goes

in. It is from cases such as this that the Aristotelian notion of matter is

derived.

The Stoics on Causality

The Stoic account of causes is both simpler and more complex than

the Aristotelian one. It is simpler in that the Stoics do not count the

material, formal, and Wnal causes as causes properly so called, and they

mock Aristotle’s followers’ ‘crowd of causes’ (Seneca, Ep. 65. 4). Their

treatment of eYcient causes, however, is more complex, in that they

adopt a canonical form for the description of causation, and they oVer a

rich classiWcation of diVerent kinds of cause. Most importantly, unlike

Aristotle, they oVer a law of universal causation, which needs to be spelt

out and defended.

The Stoics’ standard analysis of causation was of the following form:

A brings it about that B is F. A, the cause, must be a body, and so must

B; but the eVect, B’s being F, is not a body but an abstract entity, a lekton.

This is explained by Sextus:

192

PHYSICS

The Stoics say that every cause is a body that becomes for another body a cause of

something non-bodily. For instance a scalpel, which is a body, becomes for the

Xesh, another body, a cause of the non-bodily predicate being cut. Again a Wre, which

is a body, becomes for the wood, another body, a cause of the non-bodily predicate

being burnt.(M. 9. 211)

While A and B are both material entities, the Stoics used the term ‘matter’

specially to refer to B, the passive element in causation (Seneca, Ep. 65. 2 LS

55e). So in Stoic causation we have a triad of cause, matter, and eVect.

The Stoics introduced the notions of joint causes (sunaitia) and auxiliary

causes (sunerga). Two oxen are joint causes of the movement of the plough

if neither of them can pull it alone; I am an auxiliary cause if I help you lift

a load which you can, at a pinch, manage by yourself (LS 55i). The

recognition of joint and auxiliary causes was important, because it shows

that it can often be misleading to speak of the cause of a particular state or

event. Causes form not a chain, but a network.

For the Stoics it is not only changes and beginnings of existence that

need causes: there are also sustaining causes (aitiai synektikai) that bring it

about that things continue in existence. Bodies of all kinds, for instance, are

held together by an active and tenuous Xuid called pneuma, literally ‘breath’,

which is responsible for the cohesion of the universe. Living bodies are kept

alive by the soul, which is their sustaining cause. It is characteristic of such

causes that if they cease to operate, their eVects cease to obtain.

Zeno, indeed, stated this characteristic as a feature of all causes (LS 55a);

but other Stoics seem to have allowed another category of antecedent

(prokatarktikai) causes, whose eVect remained after they had been removed

(LS 55i). It seems obvious enough that a house may remain in existence

long after the builder has ceased working. What Zeno seems to have had in

mind were sustaining causes that sustained something other than existence

or life: it is prudence, for instance, that brings it about that a man is

prudent, and he is prudent only for so long as his prudence lasts. Prudence,

it must be rememb ered, was for Stoic materialists a physical ingredient of a

person (LS 55a).

The way in which the existence of antecedent causes is to be reconciled

with Zeno’s theory of sustaining causes seems to have been this: an

antecedent cause brings it about that an object possesses an internal feature

that is itself a sustaining cause simultaneous with the eVect to be explained.

This, certainl y, was the form the theory took when it was employed to

193

PHYSICS

underpin medical practice: when a patient catches a chill, the coldness of

the air is an antecedent cause, and the patient’s fever is the internal and

enduring state that is the sustaining cause of his symptoms.4

Chrysippus was famous for using the illustration of a garden roller or a

child’s spinning to p. The top will not move unless the child strikes it: but

once struck it will continue to spin ‘of its own force and nature’ (Cicero, Fat.

43). The crack of the whip is an antecedent cause, but the top’s internal force

is the principal cause. Likewise the roller, once pushed, will continue to roll

of its own accord. This illustration was used in an attempt to reconcile the

Stoic theory of causality with the possibility of human responsibility.

Causation and Determinism

The Stoics believed not just in universal causation, that is to say, the thesis

that everything has a cause; they believed also in universal causal deter-

minism, that is to say, that everything has a cause by which it was

determined. Alexander reports them thus:

Nothing in the world is or comes about without a cause, because nothing of what

it contains is independent from, or isolated from, all that has gone before. For the

world would be torn apart and shattered, and no longer remain a unity under the

governance of a single order and policy, if any uncaused motion were introduced.

That would be the case unless all the things that are and come about have

preceding causes from which they follow of necessity. (Alexander of Aphrodisias,

Fat. 191. 30 LS 55n)

Note the extreme position of the Stoics. They claim not just that every

beginning of existence has a cause, but that everything that happens has a

cause. Further they claim that every cause is a necessitating cause: given the

cause, the eVect cannot but happen. They maintain not just universal

causation, but universal determinism. This doctrine, which was to be

hugely inXuential henceforth, is a Stoic invention. It lurks no doubt in

ancient atomism (Cicero, Fat . 23), but Democritus does not spell it out with

anything like Stoic clarity. Neither of the Stoics’ causal claims was accepted

by Aristotle, and the Epicureans, while accepting the universality of caus-

ation, did not accept the universality of necessity.

4 See texts in Hankinson, CHHP 487–91.

194

PHYSICS

This uniWed, successive, inescapable series of necessitating causes was

called, by the Stoics and their critics, Fate (LS 55f). The doctrine of fate was

immediately subjected to philosophical criticism from several quarters, and

Cicero’s On Fate gives a lively account of arguments levelled against it and

Stoic responses to those arguments. One famous argument was called the

Lazy Argument (argos logos); its purpose was to show that if determinism was

true, there was no point in doing anything whatever.

The argument imagines someone addressing a Stoic patient on his

sickbed. ‘If it is fated that you will recover from this illness, then whether

or not you call a doctor you will recover; likewise, if it is fated that you will

not recover from this illnes s, then whether or not you call a doctor you

will not recover. One or the other is your fate: so there is no point in

calling a doctor’ (Fat.29LS55s0). Obviously, an argument of the same kind

can be applied to any of the normal actions of life: another source imagines

it being used to persuade a boxer that there is no point in putting up his

guard.

In response, Chrysippus made a distinction between simple and complex

facts. ‘Socrates will die on such and such a day’ may be true whatever

Socrates does; but ‘Laius will beget Oedipus’ cannot be true unless Laius

copulates with his wife. If the patient’s recovery is a complex fact linked to

calling a doctor, then calling the doctor will be no less fated than the

eventual recovery.

If the history of the world is a single tissue of interconnected events, it is

not clear how far Chrysippus is entitled to make his distinction between

simple and complex facts: perhaps Socrates’ death is co-fated (to use

Chrysippus’ term) with several of his actions, such as his behaviour when

on trial. Indeed, perhaps everything is co-fated with everything else.

Nonetheless, Chrysippus is entitled to reject the Lazy Argument.

Consider the propositions

(1) If I call the doctor, I will recover.

(2) If I do not call the doctor, I will recover.

If I am fated to recover, then the consequent of each of these propositions is

true; and if we interpret each of the propositions truth-functionally, in the

manner of Philo, each of them will on that supposition be true. In that

sense it will be true that whether or not I call the doctor I will recover. But

as these propositions are normally used in guiding behaviour, they must be

195

PHYSICS

understood not simply truth-functionally, but also as supporting the

corresponding counterfactuals

(3) If I called the doctor, I would recover.

(4) If I did not call the doctor, I would recover.

But a Stoic has no reason to accept (4).5

Determinism and Freedom

More serious was the argument that if determinism is true, human

responsibility for action evaporates, and praise and blame become pointless.

This argument was mounted both by Epicureans and by Academics.

Necessity is accountable to no one, Epicurus said, and what depends on

us, what attracts blame and its converse, must be free of the overlordship of

fate (LS 20a). To reconcile this freedom with their own atomistic system,

Epicureans hypothesized that atoms engaged in unpredictable swerves.

Thus Lucretius:

Lest mind should suVer from compulsive force

And helpless trace a predetermined course

A travelling atom deviates a space

And swerves at no Wxed time and no Wxed place. (2. 290)

Neither in antiquity nor in modern times has it been clear how such a

random quantum jerk would be a su Ycient condition for human freedom;

and not only Stoics, but Academics too, considered the swerve not only

insuYcient but unnecessary.

Carneades, Cicero tells us,

showed that the Epicureans could defend their case without this Wctitious swerve.

They taught that some voluntary motion of the mind was possible, and a defence

of this doctrine was better than the introduction of the swerve, especially as they

could assign no cause to it. By defending it they had an answer to Chrysippus:

they could agree that no motion lacks a cause without conceding that everything

that happens is a result of antecedent causes. For there are no external antecedent

causes of the operation of our will. (Fat. 33)

5 The Lazy Argument appears across the centuries in many diVerent contexts, e.g. in John

Milton’s de Doctrina Christiana in an argument against Calvinist predestination.

196

PHYSICS

Voluntary motion, by its intrinsic nature, is in our power and obedient to

us; and it is this intrinsic nature that is its cause.

Carneades is here oVering the Epicureans an answer to Chrysippus; yet

Chrysippus is reported as stating his own position in a way very similar

to that of Carneades. Chrysippus, as I remarked earlier, was fond of using

the examples of the spinning top and the garden roller to explain

causation; and he uses them to make room for responsible action. Our

assent to any proposition or proposal is triggered by external stimuli, as

the top begins to spin only when the child whips it. But the actual assent

is in our power, and this preserves responsibility without violating fate. ‘If

something could be brought about without an antecedent cause,

it would be false that everything happens through fate; but if it is

probable that there is an antecedent cause for whatever happens, what

possible reason is there for denying that all things happen through fate?’

(Cicero, Fat. 43).

The diVerence appears to be this. Carnead es denies that voluntary

actions have an external antecedent cause; Chrysippus aYrms that they

have, but appears here to deny that they are necessitated by it. How is this

to be reconciled with the universal determinism the Stoics maintained

elsewhere? To answer this question we must look more closely at the

analogy with the top. The top is set in motion by the whip, but it moves in

the way it does (a way diVerent from the motion, say, of a garden roller)

because of its own nature. Similarly, the mind’s assent, when a stimulus is

presented to it, is given because of its own nature. The assent falls under

the overarching rule of fate if it is the only possible outcome of the joint

causes, the external stimulus and the agent’s own nature. But it is not

necessitated by the external, antecedent cause, and in this sense Chrysippus

can deny that it is necessary.

Many philosophers in later ages have claimed that if a human agent is

responsible for an action X, it must have been possible for her, at the

moment of action, both to do and not to do X. Such freedom of alternative

choice was later given the technical name of ‘liberty of indi Verence’.

Chrysippus is not claiming that liberty of indiVerence is compatible with

fate: he is interested rather in what later philosophers called ‘liberty of

spontaneity’. An agent enjoys liberty of spontaneity if he does X because he

wants to do X. Chrysippus’ humans do enjoy liberty of spontaneity,

because they do X because they assent to X, and they assent to X because

197

PHYSICS