ESSAY REVI EW

The theory of everything?

Brian Ellis: The metaphysics of scientific realism.Durham: Acumen, 2009, x+179pp, £16.99 PB

Emma Tobin

Published online: 6 April 2011

� Springer Science+Business Media B.V. 2011

The aim of this monograph is to develop a metaphysics for scientific realism, which

has the characteristics of a first philosophy. In the first instance, this monograph is

an excellent chronological and philosophically honest account of the avenues,

which led Ellis to his scientific essentialism. This book takes his essentialism further

than ever before. It presents a systematic version of metaphysical realism, which

accommodates not just all of science, including the quantum world, but anydiscipline, which makes assumptions about what there is in the real world, including

mathematics, ethics, freedom of the will and many other thorny metaphysical issues.

This is a very ambitious project and even after putting the parts of the puzzle

together into an integrated first philosophy, the reader is still left with many

questions about the overall picture. Nevertheless, this is a book not to be missed by

metaphysicians.

Chapter 1 provides a discussion of the claim that metaphysics is required for

scientific realism. This is justified on the basis of a particular construal of the

relationship between science and metaphysics, namely that scientific knowledge has

limitations. The question ‘‘what sort of world would be required to accommodate

quantum field theory’’ is a relevant question, which quantum field theory cannot

answer (20). Ellis rejects semantic and epistemic accounts of scientific realism

based on theories of truth and reference, because there is no relevant theory of truth

to take on the burdensome task of explaining how truths supervene on reality. The

correspondence theory of truth cannot do the job and the semantic theory of truth

entails a commitment to realism about possible worlds.

Ellis’s project then is an enquiry into the truthmakers of science, and he argues

that a metaphysical theory of reality is required to accommodate those truthmakers.

There is a logically inescapable circle in metaphysical reasoning: namely, any

E. Tobin (&)

Science and Technology Studies, University College London,

Gower Street, London WC1E 6BT, UK

e-mail: e.tobin@ucl.ac.uk

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DOI 10.1007/s11016-011-9527-3

postulated existent is ontologically plausible only if it fits into an adequate

metaphysical theory, but any metaphysical theory is only adequate if it accommo-

dates all the things that exist. Nevertheless, Ellis makes a simple inference to the

best explanation: a metaphysics for scientific realism is the best explanation for

realism in science.

In chapter 2, Ellis assesses Smart’s original argument for scientific realism. This

argument was also an inference to the best explanation: if the world behaves as if

entities of the kind postulated by science exist, then the best explanation of this

is that they really do exist (30). Ellis favours this argument over more recent

arguments for scientific realism, all of which are committed to descriptivism, the

view that the aim of science is to give a true, generalised description of reality (25).

This kind of descriptivism is rejected on the grounds that scientific realism should

aim to account for why the theoretical entities of science explain the world, not just

describe it.

Ellis offers a further causal argument for the existence of theoretical entities:

causal connectivity characterises real entities because they have effects other than

those effects that were used to define them. This causal argument is compelling,

because we can infer two further arguments from it: the first is an argument for the

existence of properties, the properties of these entities must be capable of causally

interacting in the way that they do, while the second is an argument for the existence

of forces, fields, spatio-temporal relationships and so on. But this sophisticated

realist ontology for science is inadequate for a more general theory of what there is.

The aim of ontology, according to Ellis, is to say what kinds of elements must be

thought to exist fundamentally and to explain the ‘‘kinds of things we really need for

an ontological reduction of everything there is’’ (34).

Chapter 3 concerns scientific essentialism. Ellis formulates a more general theory

of what there is, viz. an essentialist account of natural kinds. The existence of a

natural kind hierarchy is not an empirical discovery, but more of a metaphysical

hypothesis being proposed in order to explain the exact and structured nature of the

entities that are found in science and the precise hierarchical arrangements between

them. Natural kinds are intrinsically disposed to behave in the way that they do,

because of their intrinsic causal powers. This ontology has the added benefit of

providing truthmakers for the laws of nature.

The conception of natural kinds is more liberal than in traditional substantive

accounts of natural kinds. Three categories of natural kind are distinguished:

substantive, dynamic and tropic. Where a natural kind is a generic kind, composed

of different species (e.g. chlorine and its isotopes), then any species must be a

member of the generic kind. In other words, it is impossible for there to be a species

of chlorine, which could be a species of some other element. In contrast, generic

kinds in biology do not satisfy this constraint, because the species of any genus

overlap if we go far enough back in evolutionary history.

Ellis discusses some concerns with this earlier ontology. (1) He accepts that his

earlier system was too lavish. (2) He was incorrect to include relations as natural

kinds, because many relations (e.g. numerical and spatio-temporal) relations lack a

definitive causal role. (3) Natural kinds of substance must now be construed as

ongoing physical processes, so that the category of natural kinds of objects is a

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subcategory of natural kinds of processes. At the fundamental level, the category of

natural kinds of processes must be split into two distinct kinds: the first, temporally

extended continuing processes (e.g. energy transmission processes) and the second,

spatially extended instantaneous ones (e.g. entangled electrons will remain

quantum-linked until some interaction breaks the link). This ontology while more

parsimonious retains the explanatory power of its predecessor.

Chapter 4 examines the claim often made that quantum mechanics (henceforth

QM) is a problem for scientific realism. The problem associated with realism and the

two-slit experiment in QM is that we have to accept both that Schrodinger waves are,

on the one hand, real and that, on the other hand, they do not behave as waves (they

act locally and behave like classical particles). Ellis argues that the best option for a

scientific realist is to say that the transmitted wave has the potential to reconstitute

itself into a particle instantaneously and act as a classical particle would. However,

this has extreme consequences since the known laws of mechanics are time-

symmetrical, but the scientific realist description of this quantum mechanical process

is temporarily irreversible, and thus, it contradicts the time-symmetry thesis.

Ellis argues that a version of quantum mechanical realism is nevertheless

possible, on the basis of a distinction between time-reversibility and time-symmetry.

The time-symmetry thesis states that unless there are basic laws of a radically

different kind yet to be found, there is nothing to stop the world from evolving in the

temporally reversed direction. Ellis claims that we must distinguish between two

fundamental kinds of processes: continuous states of affairs and instantaneous states

of affairs. The time-symmetry thesis is only true for continuous states of affairs. In

contrast, because the ontology required for quantum mechanics includes instanta-

neous states of affairs (because there is an instantaneous change, a quantum leap

from the state of indeterminacy to that of determinacy in the collapse of the

wavefunction) and because the process appears to have no temporal inverse,

Schrodinger waves are not time-reversible.

This is quite a move, and of course, as Ellis acknowledges, an acceptance of QM

realism involves the rejection of one of the core tenets of Einstein, viz. that the

world is essentially symmetrical in time. Ellis gives very little time to the

alternatives to his version of Schrodinger wave realism discussing Bohr, de Broglie,

Everett and Frisch in less that five pages of text. Moreover, there is no discussion

of recent collapse theories in the philosophy of physics. At the end of this

underdeveloped section, Ellis urges that the time has come to accept QM realism,

but the reader is left rather unsatisfied, given that Ellis has given his opponents

insufficient consideration.

Equally, problematic is the fact that the subsequent account of causation is based

on an acceptance of QM realism, namely if Schrodinger waves are taken to be real

and directed (that is, if Ellis is correct in rejecting Huw Price’s time-reversibility

thesis for Schrodinger waves), then elementary causal processes are real and

directed too and have nothing to do with the direction of entropy increase, nor paceHumeanism, with human psychology. Ellis’s account of causation is similar to the

proposal of Dowe and Salmon where the concept of a causal process is envisaged

as a physical event, involving a change in energy distribution. Nevertheless, Ellis

claims that his account of physical causation can be applied to all causal processes.

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Chapter 5 addresses properties. Ellis appears to move from property dualism to

property trialism. He accepts (1) causal powers (e.g. the power of one negatively

charged electron to repel another); (2) categorical dimensions (e.g. quantities,

shapes and molecular structure); and (3) those that are neither causal powers

nor categorical dimensions (e.g. the changes due to collapsing wavefronts and

radioactive decay processes) (99). Though Ellis makes this distinction and claims

that (3) is an interesting metaphysical category he does not discuss it at any length.

This is unsatisfactory, given the fact that QM realism is motivated on the grounds

of an interpretation of the collapse of the wavefunction and also given that the

subsequent metaphysical account of causation is based on the latter. Surely, it is

fundamental to the arguments that have gone before that Ellis provides a realist

account of the third category. Equally, given that at the end of chapter 3, Ellis

promised to economise his lavish 6-category ontology but is now expanding the

processes and properties subcategories, the reader is left wondering whether the

new metaphysics for scientific realism is just as lavish as his original scientific

essentialism.

Ellis argues for the inclusion of (1) and (2) above on the basis that the problems that

both face can be overcome, viz. the Meinongian argument and quidditism,

respectively. Taking the former first, the chief problem associated with dispositional

monism is the Meinongian argument; that is, anything that is the bearer of an

unmanifested disposition must point towards something that is a non-existent but

possible object: a mere possibilium. Ellis argues that this argument is flawed in that it is

committed to a possible world analysis of the truth conditions for causal conditionals.

On the converse, the main argument associated with categorical monism is

quidditism, i.e. that if the identity of a property depends not on what its bearer is

disposed to do, but merely on what it is, then we are necessarily ignorant of it. Ellis

claims that quidditism can be accepted, because a quiddity can be something that

even though it has no effects to be observed, is nevertheless observed accidentally.

For example, ‘the identity of a molecule depends on its structure and the identity

of the structure of a molecule depends essentially on what it is, not on what it does.

In [Alexander] Bird’s terminology, it is a quiddity’. (106). At first sight, this might

appear removed from scientific essentialism because the essences of molecular

kinds are their atomic structures and these atomic structures are categorical. Thus, it

looks as though Ellis is committed to the claim that the laws of chemistry are

contingent.

Moreover, the categorical monist will claim that there is nothing to stop this also

being true at a more fundamental level: the identities of atoms might also depend on

subatomic constitutions. But Ellis claims that ‘‘this process must have a natural

limit. At some stage one will have to admit that the basic constituents of the world

must behave as they do, because it is of their natures to do so, that is the basic tenet

of dispositional essentialism must be upheld’’ (114). But on what grounds should we

adhere to this basic tenet? There are several assumptions being made here; that

would not convince any of the essentialist’s opponents: (1) this process may not

have a natural limit; there may be no fundamental level to be relied upon; (2) it is

equally possible, as a structural realist for example might hold, that the subatomic

constitutions are all entirely structural.

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Why are categorical dimensions not reducible to lower-level categorical

dimensions or to structures (to satisfy the categorical monist and the ontic structural

realist on the one hand) or to more fundamental dispositional powers (to satisfy the

dispositional monist on the other)? If indeed it is to the third category mentioned

above, viz. those properties which are neither causal powers nor categorical

dimensions, then more needs to be said about it. Perhaps, Ellis has structures

themselves in mind, since he argued in chapter 4 that Schrodinger waves of particle

realisation potentials are entities that are defined by their structures (84). But

categorical dimensions are understood to be structures and relations too (93). Thus,

the discussion of properties is inconclusive and the reader is left extrapolating the

details from a comparison of the two chapters.

Moreover, this issue about the relationship between levels has implications for

the issue of the reduction of chemistry to physics. It is interesting that Ellis uses

molecular shape as the least controversial example of a categorical dimension. Yet,

recent discussions of reductionism in philosophy of chemistry have highlighted

molecular shape as a problem for reductionism. Quantum chemists have argued that

molecular shape cannot be described straightforwardly in terms of Coulombic

Hamiltonians. Thus, even if we grant QM realism, Ellis must provide an explanation

about the relationship between QM realism and molecular realism.

In chapters 6 and 7, ‘‘Realism as first Philosophy’’ and ‘‘Realism in Ethics’’, Ellis

takes the project even further showing how an ontology developed for scientific

realism could act as a first philosophy for any kind of discipline which makes

assumptions about what there is in the real world. What does this include? Just

about everything: realism about mathematics, time, freedom, personal, collective

and social responsibility to mention but a few. Though the space given to these

debates does not do them justice, one cannot help, but enjoy the grand theory of

everything presented. The philosophical honesty in this book, from one of

philosophy’s major authors in metaphysics, is refreshing and it makes it a book well

worth reading.

Acknowledgments I am grateful to Anjan Chakravartty for helpful comments on this review.

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