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WHAT IS TOKEN PHYSICALISM?
Noa Latham
The distinction between token and type physicalism is a familiar feature of
discussion of psychophysical relations. Token physicalism, or ontological
physicalism, is the view that every token, or particular, in the spatiotemporal
world is a physical particular. It is contrasted with type physicalism, or property
physicalism -- the view that every first-order type, or property, instantiated in
the spatiotemporal world is a physical property. Token physicalism is
commonly viewed as a clear thesis, strictly weaker than property physicalism,
strictly stronger than substance physicalism, and as a good statement on its own
or in conjunction with other theses of minimal physicalism.1 It is also generally
simply assumed to be true, though Davidson has offered a famous argument for
its truth, and some have argued against it. Many of those arguing against it are
substance physicalists, indicating that they believe token physicalism to be a
strictly stronger view.2
In this paper I argue that token physicalism is not a clear, univocal, thesis,
and hence does not have any useful role to play in the philosophy of mind, such
as in characterising minimal physicalism. In order to interpret and assess it, it is
necessary to specify the notion of particular under consideration and what it is
for such a particular to be physical. The kinds of particulars concerning which
token physicalism has been debated are substances, objects, events, states, and
processes. In this paper I take objects to be a special case of substances, and in
the interest of greater generality I talk mainly of substances. I do not offer here
any further characterisation of the notion of a substance or of the thesis of token
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physicalism for substances, which I refer to as substance physicalism, but have
done so elsewhere.3 This paper is concerned, rather, with what other token
physicalism theses there might be. To this end I focus on events, which I take to
be spatiotemporal particulars, i.e. particulars occupying spatiotemporal regions,
where occupying a region means existing everywhere in it and nowhere outside
it. I assume processes are a special case of events. And I suggest later that states
of a region or substance do not differ from events in a way that could give rise to
any further token physicalism theses. I take this survey to cover the entire range
of particulars for which token physicalism can be formulated. The paper is
concerned with the general claim that all particulars in the spatiotemporal world
are physical. But as mental particulars are the principal candidates for
nonphysical particulars, much of the discussion is focused on psychophysical
relations.
My strategy is to begin by attempting to unearth all the coherent event
notions there are. Then I enquire what it is for a property and a particular to be
physical, and accordingly, what token physicalism amounts to for each coherent
event notion. In the course of this I argue for an asymmetry in the notions of
mental and physical -- to be physical is to be robustly physical, while to be
mental is to have a trace of the mental. It emerges that there are two kinds of
particulars -- property exemplifications and concrete particulars. I conclude that
token physicalism for property exemplifications is equivalent to one or another
sense of property physicalism, and that token physicalism for concrete
particulars is most plausibly interpreted as equivalent to substance physicalism.
One sense of property physicalism regards all properties as identical to, or at
least nomologically coextensive with, properties drawn from sciences that are
undisputedly physical sciences. A weaker sense of property physicalism (though
I have not seen this referred to as type physicalism) merely regards all properties
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as conceptually supervenient on microphysical properties.4 Property
physicalism in the weaker but not the stronger sense has often been referred to as
nonreductive physicalism.5 Thus I conclude that token physicalism is not a
distinctive thesis strictly weaker than property physicalism and strictly stronger
than substance physicalism. And it is an unclear thesis in the sense that it
depends on unobvious claims about what particulars there are and how they are
to be characterised as physical.
I distinguish token physicalism from the stronger thesis of token identity,
which I take to embody an extra modal claim that is hard to assess and that
seems to take us beyond what people debating physicalism are most interested
in. In accordance with Kripke's arguments, token identity would claim that
every particular in the actual spatiotemporal world is physical in every possible
world in which it exists. To illustrate this, consider Descartes's claim that God
could create my mind exactly as it is in this world, but without my body.
According to Kripke, the logical possibility of my mind coming apart from my
body in this way shows that my mind is not identical with my body. To assess
this identity thesis we would need to consider how a particular is to be identified
in other possible worlds, and we would need to assess the modal claim. I shall
ignore these complications and throughout the discussion of particulars I shall be
interested in criteria of individuation that apply within the actual world,
ignoring transworld criteria. For suppose Descartes and Kripke were right and
there really were some logically possible worlds in which my mind existed
without my body. Then we would be obliged to deny token identity, since there
would be particulars in the actual world, such as my mind, which are
nonphysical in some other logically possible worlds. But there would remain an
interesting thesis naturally designated token physicalism that many may be
prepared to accept. What Descartes's audience wanted to know was not whether
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God could have created a world in which minds such as mine and yours exist
without their bodies, but rather whether my mind and yours will exist without
their bodies in the actual world, or more generally whether there are minds
separate from bodies in the actual world, or more generally still whether there
are particulars in the actual world that are not physical in the actual world. It is
the thesis that every particular in the actual world is physical in the actual world
that I am calling token physicalism and investigating in this paper.
Events and Spatiotemporal Regions
The first task is to consider what kinds of events there are. The event
notion or notions we get from ordinary language, and perhaps also from more
theoretically motivated semantic theories and accounts of causation, are usually
regarded as narrower than the notion of an occupant of a spatiotemporal region.
It is usually thought, that is, that not all spatiotemporal regions can be occupied
by an event suitable for such purposes, since many regions are too disconnected.
For example, there will be no event occupying the region comprising a point
somewhere in my apartment today and Antarctica during the Pleistocene period.
But it is fine for the purpose of examining psychophysical relations to make use
of a more general event notion. For the question of token physicalism can be
raised about any coherent notion of spatiotemporal particular, whether or not it
corresponds to a notion in ordinary or theoretical discourse. Thus I shall use
'event' to mean 'spatiotemporal particular', regarding this as a stipulation. And
in discussing the following views of events, I shall therefore focus not on how
well they accommodate ordinary event talk or fit some theory, but on their
coherence and on those differences among them which could give rise to
different accounts of what it is for an event to be physical, and thereby to
different token physicalism theses.
Events as Property Exemplifications
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A popular view of events developed by Kim6 and Goldman7 construes
them as exemplifications of a property (or relation) by a substance (or
substances) at a time (moment or interval). They can be regarded as occupying
the spatiotemporal region traced out by the spatial boundary of the substance
over the designated time. Such events are isomorphic to ordered triples
consisting, e.g., of a substance, one of its properties, and a time at which it has
the property. Some have cited ontological parsimony as a reason for simply
identifying the events with such sets.8 I prefer not to do so since these ordered
sets are not particulars but abstract entities in the sense that they do not have any
spatiotemporal location and do not occupy spatiotemporal regions.
More recently Bennett has offered a simplified version of the
Kim/Goldman view. It is that events are instances of a property in a
spatiotemporal region -- also describable as exemplifications or instantiations of
a property by the region.9 Such events are isomorphic to ordered pairs
consisting of a spatiotemporal region and one of its properties. Both property
exemplification views appear coherent, and are promising candidates for the
kinds of events people are referring to when making such claims as that it wasn't
my walking that caused my lateness but my walking slowly. On this view, my
walking and my walking slowly are distinguished by construing them as
exemplifications of different properties—the property of walking and the
property of walking slowly. (For convenience I shall refer from now on to
exemplifications of properties by regions, mentioning exemplifications of
properties by substances at times only when significant differences arise.)
There are also contexts in which people would say that my walking is the
same event as my walking slowly, but different from various other events
occupying the same spatiotemporal region, such as my smoking (assuming that
the nicotine permeates my body). One attempt to capture this kind of event
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individuation is to depart from the standard view that property exemplifications
by a given region are identical if and only if they are exemplifications of the same
property, and say instead that x's having P is the same event as x's having Q if
and only if P entails Q or Q entails P.10 This would support the intuition that my
walking and my walking slowly are the same event. But it would have the
unacceptable consequence that all property exemplifications by a given region
would be equivalent, for they would all be equivalent to the exemplification by
that region of the conjunction of all its properties. And thus it would run afoul of
the intuition that my walking and my smoking at that time are different events.
One might try to block this by barring the having of a heterogeneous conjunction
of properties, such as the property of smoking and walking, from counting as an
event in the sense at issue. However, the same problem arises if we consider not
the conjunction of x's properties but the maximal physical property possessed by
x, since on most views, higher-level properties such as being a smoking and
being a walking will be entailed by structural or functional properties of x which
will in turn be entailed by its maximal physical property.11 It is hard to see how
such event individuation could be captured by property exemplifications or any
other metaphysics of events. Before discussing token physicalism for property
exemplifications let us examine whether there are any other coherent event
notions.
Concrete Events
It is often said that events are basic, unanalysable spatiotemporal
particulars. This would be hopelessly unclear if by it we meant that, whatever
else they are, events are not property exemplifications or sets, and that we do not
need to know whether there can be more than one such event per spatiotemporal
region.12 But if it is just a way of saying, as Quine does,13 that events are contents
of spatiotemporal regions, it is somewhat clearer and may provide an intelligible
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event notion. I shall use the popular term 'concrete event' to refer to the content
of a spatiotemporal region, though the notion I am discussing is more specific
than the notion of concrete event defined by Bennett as one which contains all
the detail about the region it occupies, since, as we will shortly see, there are
further distinct event notions satisfying his definition.14 (Some seem to use the
term 'concrete event' more loosely to mean any event which is not a property
exemplification.) Concrete events satisfy the criterion of identity, offered by
Lemmon15 and recently endorsed by Davidson16, that such events are identical if
and only if they occupy the same spatiotemporal region. It follows that there can
be only one concrete event occupying a region. So if in the previous example
‘my walking’ and ‘my smoking’ are taken as referring to concrete events, they
will be referring to the same concrete event. Such events are strong candidates
for the kind of event Davidson has in mind, and I will be attempting to find an
event notion to fit Davidson's account of token physicalism for events.
Bennett has suggested a couple of ways of interpreting this notion of the
content of a region that Quine leaves unexplained. One suggestion is to ignore
the notion of content altogether. He says that it would be in the spirit of Quine's
work to say that nothing is lost if we simply identify this notion of the content of
a region with the region itself.17 Now it may be that regions are the only
particulars needed for scientific laws to quantify over. But it is natural to
distinguish between a region and what's in that region.18 And we would
automatically say that a region is physical, but I shall argue that there are
circumstances under which we would deny that its content is physical. So I shall
continue to take the content of a region to be distinguished from the region itself.
Bennett's other suggestion for interpreting the notion of the content of a
region is to regard it as the extreme case of property exemplification by a
spatiotemporal region in which the property exemplified is the conjunction of all
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the properties the region possesses.19 If all the relational properties of the region
are included, such an event would contain all the information about the entire
universe, rather as a Leibnizian substance has been thought to do. This is a
coherent event notion, but it might be thought more plausible to interpret a
concrete event as the exemplification by the region of the conjunction of all its
intrinsic properties, as such events contain no detail about regions they do not
occupy.
Property exemplification events of both these kinds are similar to concrete
events in a number of respects. They contain all the detail there is about the
regions they occupy. And there can be only one event of each kind occupying a
given spatiotemporal region. However, they appear to differ from concrete
events in that they are exemplifications of properties while concrete events are
bearers of properties. Whether one should think of concrete events as a different
kind of event from property exemplifications is hard to decide, but this does not
matter for the purpose of interpreting token physicalism. I shall argue later that
concrete events require a different account of what it is to be physical. We can
interpret this as showing that they are events of a genuinely different kind, or as
showing that there is a further way of defining a physical property
exemplification event in these conjunctive cases.
It will emerge, I think, that the notion of a concrete event is sufficiently
clear to discuss the question of token physicalism with regard to it. If it is not,
then the discussion of token physicalism would be considerably simplified.
Many authors have thought that there are events of some sort that are not
property exemplifications. The notion of a concrete event as I have characterised
it strikes me as the best attempt to articulate such a notion. As I have said, I
think that it is impossible to assess any talk about token physicalism for events
that are not property exemplifications, if nothing more is said about such events
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or about what it is for them to be physical. And I do not think that any attempts
in the literature to provide coherent alternative event notions have succeeded.
One candidate, proposed by Brand, construes events as identical if and
only if they are spatiotemporally coincident in all possible worlds.20 But this is
inadequate without an independent way of telling whether two events are
necessarily coincident.21 And a similar problem besets Davidson's original
criterion that events are identical if and only if they have all the same causes and
effects.22 Judgements concerning singular causal statements are hopelessly
dependent on judgements concerning event individuation.23
What about saying that events are changes?24 It is hard to see how this
could provide an event notion different from those already considered. Rather,
it appears that the way we use the notion of a change as a particular in ordinary
language is in classifying property exemplifications as changes or nonchanges
according to whether the property exemplified is a change property or a
nonchange property. As we sometimes talk of nonchanges as events and treat
them as causes and effects, e.g. the soldier's standing still when called upon to
salute, it would be a stipulation going beyond common usage to insist that
events are changes. Concrete events, on the other hand, are not nontrivially
classifiable either as changes or as nonchanges, except under descriptions. For
they are not associated with any particular property that might be so classifiable,
and they pretty clearly have both change and nonchange properties. Unless they
are at absolute zero temperature they will have some properties pertaining to the
motion of their internal parts, and it is hard to envisage an account of change on
which all of these would escape designation as change properties. And they will
have nonchange properties such as that of containing some oxygen (or some
other element if they contain no oxygen). So it seems all concrete events will be
classified as changes, or all will be classified as nonchanges. The notions of
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change and nonchange thus do not provide us with anything more in the way of
event notions than special cases of property exemplifications.
Some Objections to Token Physicalism
We can gain some further understanding of these event notions by
considering some objections to token physicalism for events that have been
raised without a full account of what events are and what makes them physical.
A common thread running through such objections is that no unique
physical event can be found matching a given mental event, because mental
events don't have precise spatial or temporal boundaries.25 However, this
objection can be raised much more generally about a wide range of events
couched in ordinary macroscopic vocabulary, such as Hurricane Flora, the
erupting of Vesuvius, and the spreading of Dutch Elm disease. It seems that
there ought to be a way of capturing the intuition that having no precise
spatiotemporal boundaries is no obstacle to counting all three of these events as
physical. And this would surely generalise, removing the obstacle to counting
mental events as physical. Indeed there are two ways of replying that strike me
as adequate. It is perhaps best to attribute the apparent lack of precise
boundaries to a vagueness in event names and descriptions such as 'Hurricane
Flora' and 'the erupting of Vesuvius' concerning which fully determinate region
is picked out. But one might even allow that physical events can be vague
particulars with fuzzy spatiotemporal boundaries.26 Such replies apply for any
kind of event, and could be extended to apply for any other kind of particular,
such as states or objects, for which a similar problem might be raised.
A special problem in matching every mental event with a unique physical
event might be thought to arise for token physicalism for concrete events. The
problem wouldn't arise for mental events consisting of the entire contents of a
person's mind over an interval of time. But it might be thought that there is a
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problem with intentional and phenomenal events because there are indefinitely
many such mental events occurring within a given spatiotemporal region
incorporating the brain, but only finitely many relevant ways of dividing the
region at the neurophysiological level. However, there is no reason to think that
there are indefinitely many mental events occurring within a short time interval.
The problem is more plausible for states such as believing that 2+2=4, and
believing that 2x2=4, as a person might be thought to hold indefinitely many
such mathematical beliefs at a given time. This would make trouble if states
were concrete entities. But it is far more plausible to regard them as property
exemplifications by a substance or spatial region,27 and there is no obstacle to a
given substance or region exemplifying indefinitely many properties. Returning
to the case of concrete events, even if there could be indefinitely many mental
events occurring within the brain over a given time interval, I do not think this
would show that there are some concrete events which are mental but not
physical, for we would need to argue for this on the basis of an account of what a
physical concrete event is -- an approach I will be examining shortly. Rather, it
would show that certain kinds of discourse about mental events must be
construed as discourse about property exemplifications, not concrete events.
Another problem in matching each mental concrete event with a unique
physical event arises for intentional events with wide content, since these would
have to be construed as contents of regions of space extending beyond the brain
to include the content of the thought in order to distinguish, e.g., between seeing
a daffodil and seeming to see one. In the case of beliefs about the universe it is
difficult to see what spatiotemporal region my belief would occupy and how it
could be a different region from your simultaneous belief. What I think these
reflections show, again, is not that some concrete events are mental not physical,
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but that property exemplifications may be better suited than concrete events to
capture certain kinds of mental event discourse.
The Mental and the Physical
With this account of what coherent event notions there are, I will shortly
be examining what token physicalism amounts to in each case. But first, if we
are to raise the philosophical question whether mental items (properties or
particulars) are also physical items, we need a characterisation of what we mean
by 'physical' and 'mental' in which the terms are neither mutually exclusive by
definition, nor synonymous. The truth or falsity of physicalism is not analytic.
But it may turn out upon philosophical enquiry to be a posteriori, or conceptual
but unobvious.
Let us begin the task of characterising the mental and the physical by
looking first at properties. In its broadest usage, the notion of mental property
might be thought to cover psychological properties such as being honest,
intelligent, funny, and disgusting, as well as sociological properties such as being
married, and economic properties such as being bankrupt. The best approach to
characterising mental properties, I think, is to say that these are all mental
properties, related in some way to what can be regarded as core mental
properties. It is an interesting question what this relation is. But it is
unnecessary to discuss it in order to examine psychophysical relations.
The core mental properties are phenomenal properties, such as being or
having28 a pain or a sensation of redness, and intentional properties, such as
being or having a belief, thought, desire, or intention. (Some phenomenal
properties, such as those involving perceptions and emotions, may be both
phenomenal and intentional.) Some might find this characterisation of core
mental properties unsatisfactory because it leaves out what phenomenal and
intentional properties have in common. But it does not matter for the purpose of
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discussing psychophysical relations if core mental properties are characterised
disjunctively. In fact the relation between mental and physical items may
depend to some extent on whether the mental item is (or is related to) a
phenomenal or an intentional property.
As mentioned earlier, there are two main approaches to characterising
physical properties. One approach requires a physical property to be identical
to, or at least nomologically coextensive with, a property drawn from those listed
in idealised final sciences that are uncontentiously regarded as physical sciences,
such as microphysics, chemistry, biology, and neurophysiology, but not
psychology. Such properties typically consist of an assignment of the listed
properties to all the parts of a given type of region. Another approach requires a
physical property to conceptually supervene on microphysical properties. That
is, a property A is physical according to this approach if and only if for every x
such that x is A, there is some microphysical P such that P-->A holds as a matter
of conceptual necessity. By a microphysical property I mean one consisting of an
assignment of the properties listed in idealised final microphysics to all the parts
of a given type of region. But as I want the following discussion to apply for all
reasonable views of physical properties, I will continue to talk simply of physical
properties, getting more specific where necessary.
Mental and Physical Property Exemplifications
I turn now to consider how these ways of characterising mental and
physical properties can be applied to the characterisation of mental and physical
events. As argued earlier, property exemplifications and concrete events appear
to be the only plausibly coherent event notions there are, and hence they are the
ones I shall be considering in examining token physicalism theses for events.
Bare spatiotemporal regions would not be thought of as events. But token
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physicalism for spatiotemporal regions would in any case be trivial as all
spatiotemporal regions would be regarded as trivially physical.
It seems there is no plausible alternative to defining an event which is the
exemplification of a property by a spatiotemporal region as mental if and only if
it is the exemplification of a mental property, and as physical if and only if it is
the exemplification of a physical property. On this view, as has often been
pointed out, for example by Kim,29 token physicalism reduces to property
physicalism. For if a mental event is physical, the mental property exemplified
must also be a physical property.30 So every mental property that is exemplified
in an event is a physical property. And every mental property that is
instantiated in the spatiotemporal world can be featured in a property
exemplification. Different characterisations of property physicalism give rise to
correspondingly different characterisations of token physicalism.
The situation is a little more complex for events which are
exemplifications of a property by a substance at a time, however. One might
again define such an event as physical if and only if it is the exemplification of a
physical property, and as mental if and only if it is the exemplification of a
mental property. On this view token physicalism again reduces to property
physicalism for such events. But if mental substances can exemplify physical
properties, and the resulting exemplifications would not be regarded as physical,
then we must instead define such an event as physical if and only if it is the
exemplification of a physical property by a physical substance.31 On this view
token physicalism for such events reduces to property physicalism together with
substance physicalism. And since the former uncontroversially entails the latter,
this reduces again to property physicalism.
Such a view conflicts, however, with the familiar account of token
physicalism for property exemplification events presented by Fodor. He says
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that the view that every event is physical (which he labels 'materialism',
reserving 'token physicalism' for the weaker view that all the events that the
sciences talk about are physical events) is weaker than type physicalism and
reductionism. And he explains this by saying that the contingent identity of x's
having S at t and x's having P at t presumably does not guarantee the identity of
S and P, where 'S' is a special science predicate and 'P' is a microphysical
predicate.32 But if he is right, a new criterion of identity for property
exemplification events is required, and it's hard to see what it could be. As
mentioned earlier, a criterion that takes the two events as identical if and only if
P-->S or S-->P leads to counterintuitive identifications of seemingly different
events (such as my walking and my smoking). Nevertheless, even if no suitable
alternative criterion of identity can be found to prevent token physicalism for
property exemplifications from collapsing into property physicalism, all is not
lost. The contrast Fodor is seeking between token physicalism and materialism
on the one hand and reductionism and type physicalism on the other, is
preserved on my view, albeit at a different location, as a contrast between two
senses of property physicalism. When a physical property is construed merely as
one that conceptually supervenes on microphysical properties, we get an
interpretation of property physicalism that is nonreductive. And when a
physical property is construed as one that is identical to or at least nomologically
coextensive with a property drawn from the physical sciences, we get an
interpretation of property physicalism that is commonly designated type
physicalism or reductionism.
The discussion of token physicalism has not yet taken us beyond a
discussion of relations between mental and physical properties -- whether there
are one-way or two-way conditionals connecting them, and the status of the
necessity of these conditionals.
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Mental and Physical Concrete Events
To consider token physicalism for concrete events let us begin by
returning to Bennett's suggestion that they are simply exemplifications by
regions of all their properties. Bennett argues that token identity for such events
amounts to a virtual triviality.33 Why is that? A spatiotemporal region is pretty
obviously going to have some physical properties, so the conjunction of all the
properties the region possesses will contain some physical conjuncts. But now
Bennett takes a conjunction of properties with a physical conjunct to be
physical,34 which would lead straightforwardly to the conclusion that all
exemplifications by a spatiotemporal region of all its properties are physical, and
hence would indeed reduce token physicalism for concrete events, so construed,
to a triviality. This would be an unacceptably weak interpretation of token
physicalism as it is compatible even with substance dualism (as I will show later).
However, a more plausible interpretation of token physicalism for
conjunctive property exemplifications is available. I do not think it accords with
common understanding or has any theoretical utility to say that a conjunction of
properties is physical merely because one of its conjuncts is physical. It is more
natural and plausible to say that a conjunction of properties is physical if and
only if each conjunct is physical. If a conjunctive property is to be classified
either as physical or as nonphysical, a single nonphysical conjunct would taint
the conjunction and render it nonphysical. Hence we should say that the
exemplification by a spatiotemporal region of the conjunction of all its properties
is physical if and only if all the properties exemplified by the region are physical,
thereby reducing token physicalism again to property physicalism.
The same is true for the modified version of Bennett's view in which
concrete events are taken as the exemplification of the conjunction of all the
intrinsic properties the region possesses. For token physicalism for such events
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entails the view that all the intrinsic properties a region can have are physical.
And a region cannot have a nonphysical relational property without some region
having a nonphysical intrinsic property. Thus treating concrete events as such
property exemplifications reduces token physicalism for concrete events to the
view that all the properties an event can have are physical, i.e. once again to
property physicalism.
However, I now wish to argue that when construed as bearers not
exemplifications of properties, and as contents of spatiotemporal regions,
concrete events give rise to at least one different view of token physicalism. The
main task, to which I now turn, is to say what it is for a concrete event, so
construed, to be mental or physical. One might think that a concrete event
should not be classified as mental or physical at all, but that all we should be
entitled to say is that it is mental or physical "as described" or "under a
description", which would amount to saying that the description used to pick it
out is mental or physical.35 But there is a clear sense in which we would regard
concrete events as classifiable as physical or mental simpliciter. We would
regard the content of an inert region of spacetime as physical but not mental.
And we would regard the content of a region of spacetime in which someone is
thinking as mental and perhaps also physical. We need criteria of mental and
physical concrete events which accommodate these intuitions.
Assuming the existence of a suitable language, a concrete event will have
uniquely identifying descriptions of the form '(>x)(x is the content of R)', where
'>' signifies 'the unique', and 'R' picks out a spatiotemporal region. One might
try to define mental concrete events as those with a uniquely identifying
description containing a nonredundant mental verb. But this fails to capture the
intuitive notion of a concrete event's being mental, because the definition allows
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every concrete event to count as mental. For the temporal location of R can
always be described in mental terms. As Davidson puts it,
Take some event one would intuitively accept as physical, let's say the collision
of two stars in distant space. There must be a purely physical predicate 'Px' true
of this collision, and of others, but true of only this one at the time it occurred.
This particular time, though, may be pinpointed as the same time that Jones
notices that a pencil starts to roll across his desk. The distant stellar collision is
thus the event x such that Px and x is simultaneous with Jones's noticing that a
pencil starts to roll across his desk.36
To remedy this problem we might try defining a mental concrete event as
one which can be described as (>x)(Mx and x is the content of R), where 'M' gives
a mental property of the event. As (>x)(x is the content of R) already uniquely
identifies the concrete event, the extra conjunct 'Mx' is redundant and serves only
to allow us to define mental concrete event. (Such a redundant addition to the
uniquely identifying description can be made for any property of the concrete
event.) This will not quite work, though, for we have not yet excluded from M
the troublesome relational mental properties, such as being simultaneous with
the noticing of a pencil, that come from the location of R rather than its content.
And we do not want to count a concrete event as mental merely because it has
some relational mental property, such as having amused someone, that does
come from the content of R. To capture intuitions about what makes a concrete
event mental we need to amend the proposal by requiring that M be an intrinsic
mental property. This seems to work for all mental events including intentional
concrete events with wide content if there can be such events. For if these
concrete events are contents of spatiotemporal regions extending beyond the
spatiotemporal boundaries of the person in the intentional state, then the
intentional properties can be intrinsic properties of this event. And if they are
contents of spatiotemporal regions bounded by the person in the intentional state
19
then they will have corresponding narrow content intentional properties, and
these will be intrinsic.
Likewise, it will not work to say a concrete event is physical if and only if
it has a uniquely identifying description containing a nonredundant physical
verb. For the spatial or temporal location of R can always be described in
physical terms, trivially allowing every concrete event to count as physical.37 But
this definition cannot be amended in the way just mentioned for mental concrete
events. The analogously amended definition would be that a physical concrete
event is one which can be described as (>x)(Px and x is the content of R), where
'P' gives an intrinsic physical property of the event. The amendment fails
because a concrete event could satisfy the uniquely identifying description given
above even if it contained or overlapped with the thinking or acting of some
immaterial minds. For the region's having some intrinsic physical property does
not preclude its containing an immaterial mind. And we would surely want to
bar such a concrete event from counting as physical. We would have failed to
capture the meaning of 'physical concrete event' if it followed as a trivial analytic
truth that the concrete event which has P, is the content of R, and contains the
thinking or acting of an immaterial mind is physical. This problem would not
arise if immaterial minds could be shown to be conceptually impossible. But in
the absence of such an argument, it is necessary to provide an account of the
concept of a physical event that deals with the problem.
One might respond that immaterial minds, if they were to exist, would
have no spatial location so would not occupy spatiotemporal regions. But even
Descartes came to admit a kind of spatial extension for minds, claiming that they
can be regarded as having the same extension as the bodies to which they are
united.38 If immaterial minds engage intimately in causal interactions with
physical bodies, another reasonable way to locate them in space-time would be
20
to define their spatial extension at any moment by their proximate causal
relations with the physical world. This is, after all, no different from the way we
locate physical objects. And it is no different from the way we would assign
immaterial minds a temporal location. Even if it is insisted that immaterial
minds would not occupy spatiotemporal regions, we'd want to bar an event from
counting as physical if it contained the manipulation of matter by an immaterial
mind. And this also shows what's wrong with the idea that token physicalism is
simply the view that every event is the fusion of primitive events defined as
those satisfying primitive predicates of microphysics such as 'is an alpha-decay'.
We would not want to count the fusion of such primitive events as physical if
this fusion is the work of some immaterial mind.
Consider next Mark Johnston's suggestion that physical events are those
with lawful physical descriptions defined as "definite descriptions which are
built up simply out of a predicate occurring in the antecedent or consequent of
some strict physical law plus space-time co-ordinates to secure uniqueness."39
For this proposal to be plausible as a way of defining a physical concrete event it
should be specified that such definite descriptions are to present an intrinsic
property of the event. Perhaps the actions, though not the thoughts or
sensations, of an immaterial mind could be ruled out on this view by construing
'lawful physical predicate' so as to preclude the physical description of a
spatiotemporal region in which violations of physical law occur. For on a
deterministic view of physical law, if an immaterial mind is to act on the physical
world it must do so by violating physical laws. But it is hard to see how the
actions of an immaterial mind would be excluded by Johnston's criterion on an
indeterministic view of physical law. And it still seems unsatisfactory to allow
that an event is physical if it contains the soaking up of information or plotting of
an immaterial mind, even if during that time the mind is leaving the physical
21
world alone. The mind could also be seen as engaging in acts of omission during
that period. So although Johnston's suggestion may overcome part of the
problem, it is ultimately unsatisfactory because it does not go far enough.
Furthermore, it is likely that Johnston has instantaneous events in mind
since predicates of strict physical laws naturally relate instantaneous events and
only derivatively and redundantly relate noninstantaneous events. But his
criterion would be entirely unsatisfactory for dealing with instantaneous events,
since it would counterintuitively rule as physical any instantaneous events which
include the thinking or acting of immaterial minds at that time. For it is only
through violations of physical law that immaterial minds could be detected and
excluded on Johnston's criterion. And a complete physicalistic description of an
instantaneous event would be unable to capture a violation of a physical law
since a violation is an unlawful transition from one state to the next.
As mentioned earlier, Davidson has recently endorsed a criterion of
individuation of events in terms of sameness of spatiotemporal region, so it may
well be that the events he has in mind are concrete events as I have characterised
them. Davidson's well-known argument for token event physicalism states that
mental events entering causal relations with physical events must have
descriptions fitting strict laws. But these laws must be physical. Therefore such
mental events must have physical descriptions, and hence must be physical.40 As
this argument depends crucially on taking a physically describable event to be
physical, it must be rejected for concrete events. And although the argument can
be amended to establish that such mental events must have lawful physical
descriptions, we have seen that this doesn't guarantee that they are physical
events either. Indeed the argument should be rejected altogether if, as our search
suggests, there is no coherent event notion for which we should define a physical
event as a physically describable event.41
22
I have been following Davidson in talking of an event's having a mental or
physical description, but have done so in a way that allows an equivalent
rephrasing as talk of an event's having a mental or physical property. We
needn't worry that something might have a property without falling under some
predicate, because talk of there being a description of the event of a certain form
was qualified by the assumption of a suitable language. And we needn't worry
that an event might fall under a predicate without having a corresponding
property, because I explicitly specified that the predicate in the description was
to give a property of the event.
A Psychophysical Asymmetry
In the course of this discussion we have encountered an asymmetry in the
concepts of the mental and the physical. A concrete event may be designated
mental merely on account of having an intrinsic mental property, whereas
having an intrinsic physical property does not establish that a concrete event is
physical in an intuitive or interesting sense. And the same asymmetry holds for
conjunctive properties. A conjunction of properties would appear to be mental
in virtue of having a single mental conjunct, but (as I suggested earlier) having a
single physical conjunct does not guarantee that a property is physical in an
intuitive or interesting sense. It seems that having a trace of the mental is
enough to guarantee that an entity is mental, but having a trace of the physical
does not guarantee that the entity is physical.42
Physical Concrete Events and Substances
But how then should we define a physical concrete event if we cannot
define it as one which has an intrinsic physical property? The failure of this
definition parallels the failure of the definition of a physical exemplification by a
region of the conjunction of all its intrinsic properties as one which has a physical
conjunct. Both definitions produce token physicalism claims that are compatible
23
with substance dualism, and thus are unacceptably weak. For parallel to what
we have just seen with a concrete event, a property exemplification of all the
intrinsic properties of a region should not be designated physical if an
immaterial mind is thinking or acting in the region. And the presence of such a
mind would not be ruled out by the region's having at least one physical intrinsic
property in its huge conjunction of intrinsic properties.
The exemplification by a region of the conjunction of all its intrinsic
properties is physical, I suggested, if and only if all its intrinsic properties are
physical. This definition would appropriately exclude the presence of
nonphysical minds in the region since an immaterial substance is a bearer of
nonphysical intrinsic properties. We could extend the parallel between concrete
events and property exemplifications by requiring that in order for a concrete
event to be physical, all its intrinsic properties must be physical. This definition
makes token physicalism for concrete events incompatible with substance
dualism, but reduces it to property physicalism. Indeed the close parallel
between our investigation of token physicalism for concrete events and for
conjunctive property exemplifications so far suggests that there is no significant
difference between them and that we should embrace Bennett's proposal, or the
amended version of it, that we understand concrete events as such property
exemplifications.
However, there is another way we might characterise a physical event,
that I think we should adopt for concrete events but not in general for property
exemplifications, and that would be widely regarded as giving rise to a different
account of token physicalism. Since the problem we are having with some of
these attempts at defining a physical concrete event is that they would be
satisfied by the content of a region that contained or overlapped with the
thinking or acting of an immaterial mind, an obvious suggestion is to define a
24
concrete event as physical if and only if there are no thoughts or actions of an
immaterial mind in, or overlapping with, its region. (An analogous definition
would be unnatural and inappropriate for property exemplifications in general
as the physical or nonphysical status of the properties exemplified would not
then feature in the definition. This suggests that it is better not to think of
concrete events as a special kind of property exemplification. But if one
preferred to do so, our enquiry should be construed as showing that for a special
type of property exemplification there is an additional way in which such events
are designated physical.)
This definition of physical concrete event leads straightforwardly to an
equivalence between substance physicalism and token physicalism for concrete
events, and this can be taken to lend support to the definition. To see the
equivalence, if substance physicalism is true then mental substances are physical
substances, so there will be no immaterial minds and so every concrete event will
be physical. Conversely, if every concrete event is physical, then there will be no
thoughts or actions of immaterial minds in any spatiotemporal regions, i.e.
substance physicalism will be true. (I discount the idea that there could be
immaterial minds that never do any thinking.) One reason why it is natural to
think that token physicalism for concrete events should be aligned with
substance physicalism is that every substance is closely related to a concrete
event that might be described as the substance's life. It is highly plausible to
suppose that a substance is physical if and only if the event of the substance's life
is physical. Indeed it is a trivial truth on the quite popular view that substances
just are such spatiotemporal particulars. If all concrete events are physical then
all lives of substances are physical and hence all substances are physical, so token
physicalism for concrete events entails substance physicalism. Conversely, if
substance physicalism is true, then concrete events which are lives of individual
25
minds are all physical. And if, as seems plausible, physical concrete events have
no nonphysical concrete events as parts, it follows that all concrete mental events
that are part of the life of a mind are physical. This is equivalent to token
physicalism for concrete events on the plausible assumption that all mental
events are part of the life of a mind.
The interpretation of token physicalism I am offering here would of
course be unavailable if the notion of an immaterial mind were incoherent or
hopelessly obscure. But I argue elsewhere that such a notion can be given a clear
and independent characterisation.43 In that paper I also offer reasons for denying
that having all its intrinsic properties physical is necessary for a concrete
particular (substance or event) to be physical,44 and this blocks the entailment
from substance physicalism and concrete event physicalism to property
physicalism. Here I am just assuming that substance physicalism is genuinely
weaker than property physicalism, as is commonly supposed.
The entailment from token physicalism for concrete events to substance
physicalism would not be alien to Davidson's view, since in his classification of
theories of how mental and physical events are related he lists as dualist
positions Cartesianism and 'various forms of parallelism, interactionism, and
epiphenomenalism'.45 These are all positions that are frequently classified as
substance dualist. So it is clear that he takes his token physicalism for events to
preclude substance dualism. What may come as a surprise is my conclusion that,
on its most plausible construal, token physicalism for concrete events is no
stronger than substance physicalism.
Conclusions
The thesis of token physicalism for events depends on the sort of events
under consideration and on what it means for such events to be physical. The
only plausibly coherent event notions I have found to serve as those tokens are
26
property exemplifications and concrete events. In the case of property
exemplifications it is natural to take an event to be physical if and only if the
property exemplified (and in some cases perhaps also a substance) is physical,
from which it follows that token physicalism for events is equivalent to property
physicalism in one or another of its senses.46 But in the case of concrete events
there is no obvious choice of what it is for an event to be physical. The most
plausible choice is to say that an event is physical if and only if it doesn't overlap
with the thinking or acting of any immaterial substances, from which it follows
that token physicalism of events is equivalent to substance physicalism. In the
course of the discussion an asymmetry in the concepts of mental and physical
entities emerges. Entities are mental in virtue of having a mental trace, but
physical entities are not guaranteed to be physical in virtue of having a physical
trace. Consequently, there is no event notion for which a physical event can be
identified with a physically describable event, and this undermines Davidson's
argument for token event physicalism.
The focus of this paper has been token physicalism for events. Token
physicalism for substances is simply the thesis I have called substance
physicalism and left entirely unexamined. And I have suggested that no further
token physicalism theses could come from considering processes or states. Thus
we are left finally with substance physicalism and different senses of property
physicalism from which plausible interpretations of token physicalism are to be
selected. The journey to this conclusion has not been straightforward. Token
physicalism -- the deceptively simple-sounding thesis that every particular is a
physical particular -- is not a clear, distinctive, thesis. If one is interested in
designating some thesis "minimal physicalism", the bald statement of token
physicalism is thus unsuitable on its own or in conjunction with other theses,
27
though some of the candidates I have considered as interpretations of it might
seem apt.
Department of Philosophy
University of Calgary
Notes
Examples of those taking ontological physicalism as part of a characterisation of
minimal physicalism are Hellman and Thompson “Physicalist Materialism”
Nous 1 (1977) p 310, John Post, The Faces of Existence (Ithica: Cornell University
Press, 1987) pp 125-7, and Jeffrey Poland Physicalism: The Philosophical
Foundations (Oxford: Oxford University Press, 1994). I take Davidson and many
of his followers as regarding token physicalism as minimal physicalism.
2 Jennifer Hornsby, “Which physical events are mental events?” Proceedings of
the Aristotelian Society 81 (1980-1) pp. 73-92. Horgan and Tye, “Against the
Token Identity Theory” in LePore and McLaughlin (eds.) Actions and Events:
Perspectives on the Philosophy of Donald Davidson (Blackwell, 1985) pp. 427-43.
Hereafter: AE. William Child Causality, Interpretation and the Mind (Oxford:
Clarendon Press, 1994) pp. 80-9.
3 In my “Substance Physicalism” in Barry Loewer and Carl Gillett eds.
Physicalism and its Discontents (Cambridge: Cambridge University Press, 2001)
pp 152-171.
4 See, e.g., David Chalmers’ The Conscious Mind (Oxford: Oxford University
Press, 1996) p 125.
5 Lately, this weaker sense of property physicalism has also come to be
designated reductionist. See, e.g. Chalmers, op.cit. and Jaegwon Kim, Mind in a
Physical World (Cambridge: MIT Press, 1998).
6 See, for example, his “Causation, Nomic Subsumption, and the Concept of an
Event” or “Events as Property Exemplifications”, where he changes 'object' to
'substance' so as to include such things as bits of water. Both in Supervenience
and Mind (Cambridge: Cambridge University Press, 1993).
7 A Theory of Action (Englewood Cliffs N.J.: Prentice-Hall, 1970) chapter 1.
8 Quine suggests that we might have to construe an event as the pair of a
physical object and a distinctive set, AE p. 167. And David Lewis identifies an
event with a class of spatiotemporal regions in his “Events” Philosophical Papers
Vol II (New York: Oxford University Press, 1983) p. 245.
9 Events and their Names (Hackett, 1988) hereafter: EN p 88. Bennett also refers
to these as tropes. Not all properties that the region possesses, e.g the properties
of being connected, or occurring on the earth, or occurring before 2000 AD, yield
1
28
property exemplifications that would commonly be understood as events. For
further discussion of such properties see Kim SM pp 36-7.
10 Views of this sort have been offered by Beardsley “Actions and Events: the
Problem of Individuation” American Philosophical Quarterly 12 (1975) pp. 263276, and T. Parsons “The Progressive in English: Events, States and Processes”
Linguistics and Philosophy 12 (1989), pp. 213-41.
11 See, e.g. Chalmers' section 2.5, Almost everything logically supervenes on the
physical, in The Conscious Mind (Oxford: Oxford University Press, 1996) pp 7186.
12 This appears to be the view of Helen Steward in The Ontology of Mind
(Oxford: Clarendon Press, 1997) p. 100.
13 Word and Object (M.I.T. Press: New York, 1960) p 171.
14 EN p 103.
15 “Comments” in Rescher (ed.) The Logic of Decision and Action (Pittsburgh:
University of Pittsburgh Press, 1967) pp. 96-103.
16 AE p 175.
17 EN p 104.
18 We might also want to make modal claims such as that the region could have
had a different content, or that the content of this region could have occupied
another region. But for reasons previously mentioned, I am not treating
transworld identification of events as relevant to the formulation and assessment
of token physicalism.
19 EN p 104. This in turn he represents as the fusion of all the events consisting of
exemplifications of the properties the region possesses. EN pp 145-6.
20 See his “Events as Spatiotemporal Particulars” p. 65, or “Identity Conditions
for Events” American Philosophical Quarterly 14 (1977).
21 For a critique see Schlesinger's “Events and Explicative Definitions” Mind 93
(1984) pp. 216-218.
22 Essays on Actions and Events (New York: Oxford University Press, 1980)
hereafter: EAE p. 179.
23 For the critique that led Davidson to abandon this causal criterion, see Quine's
“Events and Reification” AE p. 166, and Davidson's response in “Reply to
Quine” AE p. 175. Horgan and Tye assume such an event individuation in their
critique of token identity, 'we would claim that mental events can be
individuated only by means of their causal roles' AE p. 428. And in arguing
against token correlations, Child assumes such an individuation for mental
states, op. cit. p. 82.
24 Brian Lombard develops the view that events are changes in a substance at a
time in his Events: a Metaphysical Study (London: Routledge and Kegen Paul,
1986). And Davidson has recently emphasised in “Cause and Laws” Dialectica
49 (1995) p. 273, that the events he has in mind are changes. I do not know
29
whether he is thinking of this as designating a species of concrete event or as
marking an alternative event notion.
25 See e.g. the articles cited earlier by Hornsby, Horgan and Tye, and Child.
26 These replies can be given also to those such as P.M.S. Hacker “Events and
Objects in Space and Time” Mind 91 (1982) p. 11, and Robert Binkley “Particular
Actions” in D. Stewart (ed.) Entities and Individuation (Edwin Mellen Press, 1989)
pp. 32-4, who argue that these observations show that events do not have spatial
dimensions and thus are not spatiotemporal particulars.
27 States are continuants, i.e. spatial particulars essentially capable of enduring.
Spatial particulars individuated one per spatial region would be regarded as
spatial regions or substances. Thus there are no concrete states. As states are
property exemplification continuants they can be taken to give rise to the same
token physicalism theses as property exemplification events.
28 Substances have properties of having sensations or intentional attitudes.
States, events, and processes have properties of being sensations or intentional
attitudes.
29 See his Philosophy of Mind (Westview Press, 1996) p 60.
30 As Lewis describes events as properties, op. cit. p 245, it appears that token
physicalism for events will reduce even more directly to property physicalism on
his view.
31 And one might define such an event as mental if and only if it is either the
exemplification of a mental property by a substance or the exemplification of a
mental property by a mental substance. But the definition of mental event makes
no difference here to the thesis of token physicalism.
32 See his "Special Sciences, or The Disunity of Science as a Working Hypothesis"
reprinted in N.Block (ed.) Readings in Philosophical Psychology vol 1 (London:
Methuen, 1980) p 122.
33 EN p 146.
34 Helen Steward joins him in this assumption. She takes Bennett's argument for
the triviality of token identity to be invalid, but that is because she thinks he is
making a general case for the token identity of all property exemplifications,
rather than for the token identity of the exemplifications by regions of all their
properties, op. cit. pp. 46-7.
35 Davidson sometimes appears to talk this way, e.g. at EAE p. 215. But he
clearly considers events as mental or physical simpliciter in arguing that some
mental events are physical.
36 EAE pp. 211-2.
37 A point made, e.g. by Mark Johnston “Why Having a Mind Matters” in
AE p. 411, and by Cynthia MacDonald in Mind-Body Identity Theories (London:
Routledge, 1989) pp. 4-5.
38 In his letter of June 28th, 1643, AT III 690, and in the Sixth Replies AT VII 442.
30
AE p. 411. Macdonald claims that Johnston's suggestion at least solves the
problem of trivially rendering all events physical, op. cit. p 10. And McLaughlin
endorses this account of what it is for an event to be physical at AE p. 338.
40 EAE p. 224.
41 To put this point another way, as the conclusion of Davidson's argument -that every mental event has a physical description -- fails to preclude substance
dualism, it is thus so weak that it should not be designated a form of physicalism
at all. This is a very different point from that made by Kim in arguing that a
token physicalism such as Davidson's that lacks any account of psychophysical
property relations is a very weak physicalism. See his Mind in a Physical World
(Cambridge, Mass: MIT Press, 1998) p 5.
42 This asymmetry is closely related to Davidson's claim that 'the physical
vocabulary is, so to speak, recessive relative to the mental, in determining
whether a description is mental or physical'. EAE p. 211.
43 In “Substance Physicalism” op. cit.
44 I argue on p. 156 that such a necessary condition would wrongly exclude the
case in which concrete events and substances can be physical while having
nonphysical causally inert intrinsic properties. My claim on p. 155 of that paper
that ‘a substance could be nonphysical in virtue of any intrinsic nonphysical
properties it might have’ and the following footnote 3 should have been
corrected to express the weaker claim that a substance could be nonphysical even
if it has some intrinsic physical properties.
45 EAE p. 213.
46 A further conceivable form of property exemplification event is the
exemplification of a property by the content of a spatiotemporal region. Such an
event would be physical if and only if the property is physical and the content of
the region is physical. Token physicalism for such events thus reduces to
property physicalism conjoined with token physicalism for concrete events. And
since the former entails the latter on all interpretations we have encountered,
such token physicalism also reduces to property physicalism.
39