Connecting causal closure and its backing via physical causation

In document The chances of higher-level causation: an investigation into causal exclusion arguments (Page 95-101)

Chapter 2: Kim’s causal exclusion argument against non-reductivism

2.2 A summary of Kim’s exclusion argument

2.3.3 The empirical/inductive argument for closure Connecting causal closure and its backing via physical causation

There are at least two ways of achieving a match. One is to reformulate causal closure in terms of physical causation. The new principle could rely on a suitable version of the so-called transference theories of causation (Dowe 2008, Salmon 1984) stating that the causal relation can be reduced to the transference of some conserved physical quantity. This option has serious drawbacks.

Let us start with a problem pointed out by Gibb (2010:377). Reliance on a transference theory of causation in the premises would make the first premise redundant and render the whole project based on conservation laws empty. The best way to show this is to include the transference-based definition of causation as a premise and see what happens:

CONSERVATION: Every physical system is conservative, or it is part of a larger conservative system.

NO-ENERGY: There is no non-physical energy

CAUSATION: Causation is transference of a physical quantity from cause to effect ---

CLOSURE: Therefore, the causal closure of the physical is true

The premise concerning causation entails causal closure without the conservation and/or no-energy premises. However, this comes at a cost; the resulting new argument for causal closure is analytically valid but less informative than the former version. It basically says: everything that is caused is caused by the transference of physical energy or momentum therefore it is impossible for things to happen because of other factors. This might be true independently of what we know about conservation laws. A probably unwanted consequence

of all this is that making the conservation premise redundant in the argument makes the original question concerning the empirical support for closure obsolete. To have a meaningful discussion concerning the support conservation laws provide for closure and physicalism, which is the only properly worked out empirically based defence, one has to find a different way of formulating the whole argument. Instead of getting rid of the original premises, one should make the relation between the body of supporting evidence relied on by most physicalists, conservation and no-energy, and the conclusion, causal closure, as explicit as it can be.

I think, it would be false to say that there is no motivation for relying solely on physical theories of causation as a starting point. Proponents of transference theories like Dowe or Salmon had reason to go with this idea. Being naturalist philosophers, they turned to science for answers concerning causation and their reasons for believing that physics might provide a good answer are similar to the reasons we can provide for believing in physicalism as a general metaphysical doctrine. The no-energy and conservation premises do provide direct motivation for the causation premise. If all physical energies/quantities are conservative, there are successful reductions of certain macro-level properties and seemingly non- conservative physical forces reduce to fundamental level conservative forces and there is no evidence for the existence of other kinds of energy then it is plausible to think that in this world the causal relation reduces to the transference of conserved physical quantities inside the physical realm. So, one way to go is to regard the causation premise as an intermediary conclusion between the original premises and the original conclusion:

CONSERVATION: Every physical system is conservative, or it is part of a larger conservative system.

NO-ENERGY: There is no non-physical energy

--- CAUSATION: Therefore, causation is transference of a physical quantity from cause to effect

CAUSATION: Causation is transference of a physical quantity from cause to effect ---

CLOSURE: Therefore, the causal closure of the physical is true

Note, that the argument for physical causation is as vulnerable as the argument for closure was. For example, one might say that there is still room for finding special energies in some context or another we still don’t know enough about. But, this is uninteresting, in Papineau’s treatment the whole idea of closure is predicated on the plausibility of the no energy premise, so to reject physical causation we need points that only apply more specifically to the argument for physical causation.

The first line of argument against the physical reduction of the causal relations might be the following. It is fair to say that starting with physical causation would commit one to a radically reductive view of causation, a view that begs the question against any metaphysical views opposing physicalism, like interactive dualism or ontological emergence. If causation in general is identified with physical causation, then no other “mechanism” for causal “doing” is possible. Even if one believes in some form of physicalism about our world it does not follow that there are no possible non-physical worlds or that there are no non-physical entities in our world in causal interaction with each other even though they are not in causal interaction with the physical realm. Even the causal closure of the physical realm applied to our world is compatible with the existence of non-physical things isolated from physical goings on and

causation between them that is not based on physical mechanisms. Therefore, even if there are good empirical arguments for reducing causation to physical causation at least in our world it would be too hasty to do so. If possible, it is advisable to find other ways to argue for the causal closure of the physical.

Furthermore, to rely on less metaphysical, more sober-minded arguments it is enough to attend to some empirical facts concerning higher-level causal relations in our world. Phil Dowe, a major contemporary proponent of the transference view of causation, says this:

“ suppose that the conserved quantity theory will deal with causation in other branches of science [outside physics] also requires commitment to a fairly thorough going reduction, since clearly there is nothing in economics or psychology that could pass for a conservation law.” (Dowe 2008, section 6.6)

The idea is the following: if, at present, most higher-level properties/quantities don’t seem to reduce to basic level physical goings on in any straightforward manner and, as Dowe pointed out, there are no insights concerning many important higher-level quantities suggesting their conservativeness then it is an open question whether causal relations determined for these quantities can be reduced to the transference of basic physical energy. This thought provides empirical motivation for the view that it would be too hasty to accept physical causation on the evidence at hand and therefore a more permissive theory of causation should be relied on.

There are also plausible arguments against accepting physical theories of causation as good theories of causation. Transference theories of causation suffer from well-known internal problems. They have certain advantages compared to the metaphysically more neutral counterfactual theories, as they can avoid problems concerning negative causes or

effects or those of late pre-emption(more on this in section 2.5.3), but at the same time they suffer from a serious and notable disadvantage: transference theories have a hard time handling problems of causal relevance. A theory of causation should be able to differentiate aspects of the cause that are relevant for bringing about some effect from aspects that are not. But from the point of view of most physical theories any physical transmission between the cause and the effect counts as a causal relation which results in so called causal misconnections, failures of causal relevance (see: section 2.5.4). This is the main reason why most philosophers agree that physical theories of causation only provide necessary conditions for causation, but the theory is not good enough to provide sufficient conditions. Metaphysically more neutral theories like counterfactual theories are better in handling this issue. And they have a further advantage, they can incorporate non-physical causes into causal discourse. Taking the above worries seriously provides sufficient motivation for the conclusion that even if there are no positive arguments for the existence of special higher- level or non-physical causes, we should leave the door open for that option.

Let us turn to the second step of the argument, the inference from physical causation to closure. If causation is physical causation, then it is obvious that there can be no non- physical causation. So, mental causes are excluded from the get-go. The good news is that the premise seems to entail physical causal closure. But, is this really so?

There is at least one argument against the validity of this inference. According to our best scientific knowledge it is possible that there are uncaused events in the physical realm (the received example is radioactive decay in the case of a particular atom where it is impossible to predict the exact time of decay39). This is something that the causal closure

39 For interesting interpretations of uncaused physical events and their non-causal powers see Lowe (2013),

argument wouldn’t necessarily allow for in its canonical formulation. If every physical effect at time t1 has a sufficient physical cause at time t1 then there can be no uncaused physical

occurrences as every physical effect has a cause. However, this problem can be easily avoided by clarifications of the terms used. In case the term “physical effect” refers to a physical occurrence that is caused by something, either a physical or a non-physical cause, then uncaused physical occurrences fit neatly into the picture.

Unfortunately, there is also bad news concerning the argument from physical causation. Not only the conservation and no energy premises are made redundant by this premise in the previous version of the argument, but in case one plugs this into Kim’s physical causal exclusion argument, replacing more permissive versions of the causal closure premise, it makes redundant the no overdetermination premise. In case the no overdetermination premise is dispensed with, the exclusion argument becomes quite empty or in other words it becomes more of a statement than an argument. (See: Lowe 2000:571-573).

Kim formulated causal closure in a way that allows for non-physical causation. His version of the causal closure principle only states that every physical effect has a sufficient physical cause. This does not exclude mental events as causes of physical events. However, formulating causal closure in terms of a transference theory excludes mental causes from the get-go and by doing that begs the question against possible opponents. From physical causation it jumps to the conclusion that mental causes cannot be distinct from physical causes as there are no mental causes. I agree with Kim (2005:51) that there is a philosophical gain to be had from separating the causal closure principle from the no overdetermination and exclusion principles. These have different sources of support. Closure only has empirical support or opposition whereas the no overdetermination premise of the exclusion principle is considered to be analytically true by Kim, while others like Menzies and List (2009) and

Raatikainen (2010) think that it is far from it (more on this in sections 2.4 and 4.1). By keeping the two premises separate we render the exclusion argument more interesting in terms of its content and avoid begging the question against interactive dualists and other opponents of physicalism. This is a serious reason why physical causation is a bad candidate for a starting point if one wants to argue for physical causal closure.

To sum up, physical causal closure is entailed by the physical causation premise, but the premise is too strong for two main reasons: (1) it makes the conservation premise redundant and (2) that version of the argument pre-empts the causal exclusion argument. Therefore, we should try a different approach.

There is one interesting insight from the discussion of closure based on physical causation we should incorporate into an amended formulation of physicalism. The plausible existence of uncaused physical events requires a modification that allows for them. Reacting to arguments from Lowe (2000), Kim (2005:43) defines closure in the following way:

Causal closure: If a physical effect has a cause that occurs at t, it has a physical

cause that occurs at t.

In document The chances of higher-level causation: an investigation into causal exclusion arguments (Page 95-101)