Commentary on Mumford’s “ Polygeny and Pleiotropy”
In “Polygeny and Pleiotropy” presents a case for the existence of a power ontology. Real powers
that produce the world of events as we perceive it. The central aim of the paper is to urge the
acceptance of powers as real things operating in the world. He gives three main arguments why we
should accept this ontology. The first one, and more important, is that it gives a plausible theory of
causation, one which would allow us finally to get in the road of a better understanding of the
phenomenon. This new theory involves a radical reconceptualization of causal connections. In
order to motivate the acceptance of this reconceptualization, offers two other arguments: the first
concerns the role of metaphysics in philosophy. Some theorists believe that metaphysics is a
branch of philosophy that is constrained by certain platitudes about the phenomena they study
(such as Lewis and Jackson’s Canberra plan). In contrast, others (such as Putnam and Quine) think
that it works as an empirical science: metaphysics is an posteriori matter that considers laws,
proprieties, events, etc, in an abstract and general way. According to Mumford, both conceptions of
the metaphysical tasks must be rejected so to make room for a Socratic critical philosophy, which
is conceived of as the proposal of a metaphysical framework independent of both considerations of
common sense and empirical knowledge.
Secondly, Mumford argues in favor of the ontology of powers saying that this is the best explanation
that we have for the following phenomena: cases of causation where no cause is distinguished,
cases of causation by omission, cases of simultaneity of possible causes, cases of different causes
acting against each other.
To sum up the three arguments: if the ontology of powers gives us the best explanation of
causation, we should let the new metaphysical insight guide our empirical investigations and correct
our common sense intuitions about what we take to be the typical cases of causation.
In this commentary I will argue that what Mumford offers us as an explanation of causation ends up
being something close to the Humean position. If that is so, we will need a further argument to
accept the existence of powers. What I’ll be trying to rebut is the claim that the kind of phenomena
that are in question get a better explanation in the new metaphysical framework of powers, I won’t
argue that these explanations are equivalent in any other sense. My strategy will be the following.
First, I will present the ontology of powers offered by Mumford as an alternative to the Humean
conception of causes. Then, I will argue that in giving the identity criterion for powers, Mumford
needs to correlate each power with a counterfactual conditional, just the kind of conditionals that
play a fundamental role in the Humean paradigm. Finally, I will show that the examples given by
Mumford can be accounted for within the Humean framework. The corollary will be that we still can
ask which one is the better explanation of the phenomena in question.
1- An Ontology of Powers
Humeans usually affirm that all there is to say about causation can be said with the establishment
of a true conditional that expresses a regular correlation between one kind of events and another (
Hume 1748, Sec VII, part II). Hence, according to M, we need to replace this image by one in which
we start by proposing the existence of powers that produce manifestations, where the relation
between a power and its manifestations is one of necessary connection.
The main idea is that powers can make for an explanation of those cases where the cause is
operating without giving rise to any specific event. The following paradigmatic example has been
giving by Martin in “Dispositions and Conditionals”. If a live wire is touched by a conductor, the
electrical current flows from the wire to the conductor. Martin proposes then to conceive of a
machine, called the electrofink, connected to the conductor, in such a way that each time that the
conductor touches the live wire it makes it dead –and live when dead. Since powers need not
always manifest themselves through Humean events, the example does not pose a problem for the
ontology of powers. A similar example is given in terms of the force of gravity operating over a
magnet on the fridge: we can say that although the magnet doesn’t fall, the force is acting. The
manifestation event is hidden.
On the other hand, we have cases where it is not clear that there is only one event causing the
effect. This is the case of the barge that is drawn down a canal by a horse on each bank (Molnar
2003): on the northern bank a horse produces a force north west, while on the southern bank a
horse produces a force south west. Neither force is able to display itself unfettered. The forces both
pull west but also pull against each other on the north-south axis, this produces that the barge
moves down the center of the waterway, in a westerly direction, rather than crashing against either
side. To explain this type of case, Mumford elaborates the idea that powers cause events
polygenically –meaning that the events are produced by many powers acting together with small
additive and sometimes subtractive effects- and pleitropically- meaning that they contribute to many
different events at different times or at the same time in different places (this is what the
trnsfactually image allow us to say)
2- The identity of powers
Now, one can ask how we can establish the identity of each power. Regarding this point Mumford
says that there is a connection between a power and its manifestation which is essential. Hence,
Mumford states that the identity of a power is specified in terms of the manifestation of which it is a
power for. But Mumford also holds that the power in question is the cause of the manifestation
(power explains causation and not the other way around), and
since the identity of the power is
fixed by that of the manifestation the causal relation in question is necessary.
This can be specified by saying that the following definition is true:
X is P =df x has some property S ( and S is the cause of x G-ing if x F-ed in conditions Ci)1
This relation is an essential one: the power wouldn’t be the power it is unless it is the power to be
manifested in that way. This means that in certain conditions -maybe ideal ones- a determinate
effect will follow from the presence of the object which is said to possess the power plus a triggering
or a releasing event; i.e., if sugar is soluble then, necessarily,
in certain ideal conditions, the
dissolution of sugar will follow from the immersion of that sugar in water.
It is true, as we can see in the examples quoted before, that we do not need the manifestation to
actually occur in order to affirm the connection between the ascription of the power and
the
conditional describing the manifestation. We may say that even if the event doesn’t actually occur
we have a true counterfactual conditional that enables us to identify the powers in counterfactual
situations ( i.e., the contribution of the force of gravity in the example of the magnet on the fridge
requires, in order to be identified, that that there is a possible situation where the magnet actually
falls by the attraction of the force of gravity, i.e., where the attraction of magnet to the fridge its
weakened).
So, it seems that in order to establish the identity of each power we need to correlate each one of
them with a counterfactual that describes the corresponding manifestation, even if, as Mumford
argues, in the actual world, we may not see this power operating in isolation because of the
pleiotropy and the polygeny of
these phenomena. So, given this close connection with
counterfactuals, I wonder whether a supporter of the Humean framework could not steal the trick ,
and use those counterfactuals to exhaustively account for causation.
I think that the examples given by Mumford admit a redescription in terms of counterfactuals, which
will count for a Humean as cases of Humean causality. Let’s take for instance the example of the
1
This is the Rylean equivalence between a disposition and its manifestation, X is D ( ie solubility) =df If Fx
in conditions Ci then Gx . ( If submerged in water in ideal conditions, then it will dissolve), plus the causal
relation (Mumford (1998, chap . 6 Dispositions))
barge. A Humean could describe this case by saying that there is a regular correlation so that “any
time that the barge that is drawn down a canal by a horse on each bank one on the northern bank
which moves north west, while on the southern bank the other moves south west, the barge moves
down the center of the waterway, in a westerly direction, rather than crashing against either side”.
Now, in the case where one of the horses were missing, the barge would crash against the sides,
which means that the presence of each horse causes the barge not to crash and to move down the
waterway.
As far as the magnet example is concerned, it is a case where the gravity force does not cause the
magnet to fall because the conditions for the corresponding regular correlation to take place are not
satisfied. On the contrary, if such conditions were given, for instance by way of the weakening of
the magnet, the object would fall. The gravity force can be thus taken to be operating even when
the manifestation event does not occur because of an interfering force.
The Humean can say that the ascription of a causal connection requires the satisfaction of a set of
ideal conditions that include, for example, that no other events that could inhibit the effect took
place. By contrast, in an appropriate counterfactual situation, given the cause, the effect would
follow. Roughly C caused E just in case C had not occurred E would not have. Or in the nearest
possible world where E fails, C fails too 2 This means that Humeans can make room for that kind of
phenomena without submitting to an ontology of powers, just by accepting the conditionals and the
framework of possible worlds, conceived of as hypothetical changes in the states of affairs. 3
What I am trying to rebut is Mumford’s claim according to which the previous examples get a better
explanation in the new metaphysical framework of powers. It may be worth emphasizing that I am
not taking Mumford’s explanation to be equivalent to the Humean in any other sense.
3- Final remarks
To sum up, Mumford tells us that the best explanation of what takes place is to think of a world of
powers that underlies the world of events. Nevertheless, if what I have said is true, much of what
this new ontology of powers can explain could be also be explained by a Humean, without the
ontological commitment to powers. My question then is: is Mumford’s explanation of the
phenomena of causation really better than the Humean one? and if it is not, then what reasons do
we have to accept the existence of powers?
It is worth noticing, that it is difficult to see why a strong ontological commitment is thought to
produce much more progress in philosophy than a poor one, as Wittgenstein and others thought:
one can be persuaded instead that the compromise with metaphysical truths previous to empirical
2
See Lewis Philosophical Papers II , Oxford: Oxford University Press, ( p. 159-84)
In the case of the Humean account the counterfactual would be constitutive of causation ( this is different
from Mumford’s account although this is not relevant for the point I’m stating)
3
investigation or to our common intuitions can turn out to be more of a dangerous dogmatism than
an exercise of Socratic critical philosophy. Perhaps, after all, the Euthiphro question remains open.