Reduction and Elimination in Philosophy and the Sciences

tween the two approaches. The task of both Antony’s and
Kim’s metaphysical projects is “back to basics”.
For Antony, reductive explanation of psychological
regularities in terms of basic physical entities and
mechanisms constitutes the necessary metaphysical
condition for an explanation to be true. We need ‘a
systematic account of mental phenomena in terms of
physical microstructures’ (Antony, Levine 1997, 94-ff.).
Although—for Antony—there are regularities that cannot
be apprehended at more basic levels of descriptions, such
as those of psychology, these ‘entail the existence of some
ultimately physical mechanism’, ‘a pattern of lower-level
events that guarantees, contingent on features of the
background, the emergence of some higher level
regularity’ (Antony 1995, 441).
The same holds for Kim. In fact, whether or not
reduction succeeds depends on the possibility to identify at
least the sufficient condition for the higher-level property to
inherit its causal power from its lower-level realiser, in
order for higher-level generalisations to be linked with
“real” entities and mechanisms: ‘The psychological
capacities and mechanisms posited by a true
psychological theory must be real [italics mine], and the
only reality to which we can appeal in this context seems
to be physical reality’ (Kim 2006, 161). Macrocausation,
i.e. causation at any higher level, can be proved to be
“real” only if systematically linked to microcausation, i.e.,
the causation at work at the bottom physical level, out of
which it emerges (Kim 1993, 100).
For both Antony and Kim the real causal job is only
done by “real” entities, i.e., entities which belong to the
ultimate ontology of the layered world. Any higher-level
observed regularity is maintained by some “genuinely
causal” interaction between ontologically prior physical
entities. Thus, mental laws describing these regularities
have explanatory force only if linked to microphysical
causal mechanisms. Some interesting questions arise.
First: What is the “genuine” feature of the mechanisms at
the microlevel which guarantees the truth of explanations
at higher levels? Secondly: What are the “real” entities
involved in these mechanisms?
Antony claims that a ‘physical model of causation’ is
to be applied to mental events (Antony, Levine 1997, 102),
but, regrettably, she does not go much further. It is clear,
however, that this model of physical causation is neither
regularity-based nor counterfactuals-based, insofar as
these are exactly the kinds of causation—holding for the
mental—that she is not satisfied with.
Kim shares the same perplexities but he is much
more explicit (Kim 1998, 45, 71; Kim 2007, 230-5). The
problem of mental causation cannot be resolved by
invoking a regularist-nomological or a counterfactualdependence
approach to causation, real causation being
“production”, or generation. What Kim means by model of
causal production is something close to a Salmon-Dowe
conservative quantity theory of physical causation (CQ)
(Kim 2007, 240 n.13; Dowe 1992; Salmon 1994). Kim’s
reasons for preferring this kind of causation are that only
the notion of causal production (i) permits the distinction
between real causal processes and pseudo-processes—
i.e., processes generating accidental, non-lawlike,
regularities, rendering dispensable the use of nomological-
and counterfactuals-based regularities (Kim 1993, 93-ff.;
Kim 1998, 45; Kim 2007, 231) and (ii) has the
characteristic of locality, for which ‘causes are connected
to their effects via spatiotemporally continuous sequences
of intermediaries’—i.e., generate their effects via
Mental Causation and Physical Causation — Lorenzo Casini
processes which propagate in spacetime along a
continuous trajectory (Hall 2004, 225; Kim 2007, 235). As
Kim puts it, human agency, i.e., the capacity to perform
actions in the physical world on account of beliefs, desires,
etc, ‘requires the productive/generative conception of
causation’ (Kim 2007, 236). Thus, mental causation can be
secured and explained only by backing psychological
regularities to causally productive mechanisms.
4. The ‘reality’ of microcausation
Unfortunately, there are strong reasons to doubt that production
can do the job. In fact, this model does not apply to
those phenomena where action-at-a-distance seems to
occur (Hall 2004, 226, Salmon 1984, 210, 242-59; Salmon
1998, 23, 224, ch. 16). In fact, there are quantistic phenomena,
where no continuous spatiotemporal process can
be identified, such as the well-known problem of EPR
causal anomaly—it takes the name of Einstein, Podolsky,
and Rosen, who formulated it in 1935, charging quantum
mechanics of incompleteness. Consider a quantum system
consisting in an atom of positronium—a positron (positive
electron) and a negative electron orbiting about one another.
The system’s total intrinsic angular momentum, or
spin, is zero. Let the particles be separated from one another
without affecting the angular momentum of the total
system or of either parts. The EPR problem is that a
measurement performed upon the positron seems to influence
the physical state of the electron, even if there is no
physical interaction between the two at the time of the
measurement. The enigma is how the remote parts of the
system can react instantaneously, i.e., without the medium
of a causal process in spacetime, to a local interaction with
one of the parts. This is the ground for Einstein’s opposition
to quantum mechanics: either quantum mechanics is
incomplete—i.e., there are “hidden variables” explaining
the phenomenon, or the relationship between momentum
and position is “non-real” (Mehra 1974, 70-1). However, no
later studies have discovered the presence of hidden variables
and dissolved the problem. As Salmon himself admits,
a single consistent description that explains what
happens in terms of spatiotemporally continuous causal
processes and local causal interactions cannot be given
for the quantum domain (Salmon 1984, 245).
Quantistic phenomena are currently considered
genuinely and irreducibly stochastic. Obviously, this does
not exclude that quantistic laws are incorrect, or that
quanta are not the ultimate microparticles, but I do not see
how it can suggest that causal production is at work at the
microlevel. Interestingly enough, Kim’s desideratum of
locality, as a continuous sequence of causal intermediaries
in spacetime, cannot be met exactly with reference to
mechanisms involving the physical entities of the
microlevel. Appeals to regularities or counterfactuals are
not dispensable at the microlevel. Does this mean that we
have to deny the ‘reality’ of the phenomena of quantum
mechanisms and treat them as pseudo-processes? Or can
we be content with a causal explanation in terms of
statistical correlations, i.e., a regularist approach?
Notice that Kim (2007, 232) concedes that only
regularities and Humean “constant conjunctions” may be
present at the microlevel. For him, this means either that (i)
‘it makes no sense to speak of “underlying” mechanisms,
or “real” causal processes at a lower level’, or that (ii),
‘although only “constant conjunctions”, but no causation,
exist at the fundamental level […], causal relations can,
and do, exist (or “emerge”) at higher levels’.
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