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Scientific Essentialism is a view that has received increased attention within recent works[1]. Two central features of this view are:
(i) “…inanimate matter is not passive, but essentially active,” and
(ii) “…anything that belongs to a natural kind is logically required (or is necessarily disposed) to behave as its essential properties dictate.”[2]
What Ellis takes to be the opposing view is the “Humean” position which has as one of its central features being:
(H)“…things behave as they are required to by the laws of nature.”[3]
The question can easily be raised, if matter is active, its activity is the result of its essential properties, and its activity is not required by the laws of nature, then what reason do we have to think that there are laws of nature when activity comes from matter? Stephen Mumford[4] has answered such a question in the negative. Mumford points out many problems with essentialism, but his rejection of laws seems (as I will argue) more in line with scientific essentialism.
Another position that scientific essentialism is committed to is scientific realism.[5] Scientific realism, according Richard Boyd, maintains the “…product of successful scientific research is knowledge of largely theory-independent phenomena and that such knowledge is possible (indeed actual).” [6] It has been argued that a significant number of scientific theories have been acquired through the application of simplicity. If theory T1 is simpler than theory T2 then we should choose theory T1.The scientific realist (essentialist) can easily ask the following questions, if a theory is chosen because it is simple then does the theory have anything to do with the theory-independent phenomena?
If such a question does not have an acceptable answer for the scientific essentialist then the scientific essentialist must reject simplicity as a characteristic of a good theory. This creates a dilemma for the scientific essentialist, (1) Thomas Kuhn[7] maintained that, historically, some scientific theories have been accepted because they were simpler than the alternatives; (2) Hugh Gauch’s[8] account of scientific practices maintains many scientific theories apply simplicity when dealing with the “curve-fitting problem.” Mario Bunge[9] and Richard Boyd[10] have argued that the historic importance of simplicity has been exaggerated by philosophers of science and really has little or no importance when choosing between scientific theories.
What remains is the “curve-fitting problem.” Elliot Sober[11] has produced a number of works attempting to maintain both scientific realism and justify simplicity within such a doctrine. After reviewing the various works concerning these topics, I have concluded that simplicity is inconsistent with scientific essentialism by an argument that will be presented within this paper. If such an argument is correct then I foresee two options either another account of simplicity needs to be given or simplicity needs to be abandoned for some other notion within scientific essentialism. While I leave the former as a possibility, my focus will be on the latter. The dispositional account of science suggested by Mumford[12] gives a better interpretation of scientific essentialism.
[1] See Bird (2005, 2007), Mumford (2004, 2005), Heil (2005), Ellis (2001, 2002, 2005a, 2005b), Lowe (2006)
[2] Ellis (2002) p. 59
[3] Ellis (2002) p. 59
[4] See Mumford (2004)
[5] See Ellis (2002) p. 23-25, But scientific realism isn’t necessarily committed to scientific essentialism. See Mumford (2004, 2005) and Tiercelin (2007)
[6] Boyd (2002), Introductory Paragraph
[7] See Kuhn (1977)
[8] See Gauch (2003)
[9] See Bunge (1963)
[10] See Boyd (1989)
[11] See Sober (1975, 1988, 2001)
[12] See Mumford (2004)
If theory T1 is simpler than theory T2 then, all other things being equal, we should choose theory T1. Such a conditional, according to Alan Baker[1], most philosophers would accept. This has created a problem for those philosophers that accept the doctrine of scientific realism, whether or not to reject the notion of simplicity as a characteristic of a good theory. Scientific realism, according Richard Boyd[2], maintains the “…product of successful scientific research is knowledge of largely theory-independent phenomena and that such knowledge is possible (indeed actual).” The scientific realist can easily ask the following questions, if a theory is chosen because it is simple then does the theory have anything to do with the theory-independent phenomena? Why think that the simpler theory is more likely to give us knowledge of these theory-independent phenomena?
If such questions do not have an acceptable answer for the scientific realist then the scientific realist must reject simplicity as a characteristic of a good theory. This creates a dilemma for the scientific realist, (1) Thomas Kuhn[3] maintained that, historically, some scientific theories have been accepted because they were simpler than the alternatives; (2) Hugh Gauch’s[4] account of scientific practices maintains many scientific theories apply simplicity when dealing with the “curve-fitting problem.” If the scientific realist rejects simplicity then either she needs to maintain all of the theories where simplicity was applied as unjustified or give some other interpretation as to why these theories are correct. Mario Bunge[5] and Richard Boyd[6] have argued that the historic importance of simplicity has been exaggerated by philosophers of science and really has little or no importance when choosing between scientific theories.
What remains is the “curve-fitting problem.” For over the past 30 years, Elliot Sober[7] has produced a number of works attempting to maintain both scientific realism and justify simplicity within such a doctrine. After reviewing the various works concerning these topics, I have concluded that simplicity is inconsistent with scientific realism by an argument that will be presented within this paper. If such an argument is correct then I foresee two options either another account of simplicity needs to be given or simplicity needs to be abandoned for some other notion. While I leave the former as a possibility, my focus will be on the latter. The dispositional account of science suggested by Mumford[8] gives a better interpretation for the scientific realist.
Given OR and assuming entities either exist or they don’t exist there is no circumstance where two theories are equally accurate and differ in terms of simplicity. In order to demonstrate this let us suppose that some theory, T1 is more complicated than another theory, T2. The only way for T1 to be more complicated than T2 (given OR) is for T1 to postulate more entities than T2. This means that T1 says that the entities not mentioned within T2 are present within the world. The number of entities that they postulate has to be different in order for one theory to be more or less complicated than another.
Let us consider the most basic case possible where one theory is more complicated than another, T1 postulates only 1 entity and T2 postulates 0 entities. This means T1 is more complicated than T2. How could T1 and T2 be equally accurate? T1 postulates only 1 entity and in order for T1 to be accurate that entity has to exist. T2 postulates no entities and so if T1 is accurate then there is no way that T2 can also be accurate (since the world would contain only 1 entity and no entities). If T2 is accurate then there is no way for T1 to be accurate.
Considering the next possible case, T1 postulates only 2 entities and T2 postulates only 1 entity. The same situation is present, T1 postulates only 2 entities and either those entities exist or they don’t. T2 postulates only 1 entity and so if T1 is accurate then there is no way that T2 can also be accurate. If T2 is accurate then there is no way for T1 to also be accurate. This can be shown no matter how many entities are postulated in T1 or T2. It is not possible for two theories to differ in terms of simplicity and be equal in terms of accuracy.
Sober says something very interesting with respect to the notion that simplicity is evidence for the truth of a theory. If we consider simplicity as the mechanism that gives us a line for some scientific theory then it doesn’t like simplicity is evidence for truth. I remember the line fitting problem (or curve fitting problem) being describe to me in this manner (from Dr. Symons’ Philosophy of Science course). If you can remember from any science course you took in high school then you probably did some simple experiments and recorded what happened in that experiment. Now the text probably had a law that made a claim about how the experiments should come out. After you record the data and map them out on a graph you will not have a straight line like the law says. You have something more jagged. The law itself is a straight line.
Such a situation makes for an interesting dilemma, as Sober points out, “…theory that goes beyond the evidence by systematizing what appear to be unrelated data is simpler, and less probable, than the evidence itself.” (Sober 1975 p. 166) Which goes against what Popper (1968) and Quine (1966) argue. They argued that the simpler theories are more likely to be true, but Sober notices that the reverse is actually true. Applying simplicity reduces what the data actually tells us, we are sacrificing truth in order to get the line to fit. At the same time, if we don’t apply simplicity then a theory has no predictive powers. This does put us in a rather awkward situation, if we are more interested in truth, we should reject such theories. If we are more interested in accepting those scientific theories that apply simplicity and have some predictative ability then we should accept such theories. At the moment, I can’t really see any justification for making the move from the data to the line.
I noticed that Sober has made an interesting change somewhat recently concerning his views of simplicity, “Just as the question ‘why be rational?’ may have no non-circular answer, the same may be true of the question ‘why should simplicity be considered in evaluating the plausibility of hypotheses?’ (Sober 2001 p.19) Baker asserts that Sober is trying to justify ’simplicity’ in terms of something ‘intrinsically valuable’ to simplicity itself, but I am not sure what that means.
Well, even though I am not done with my Contradictory Beliefs paper (it is taking me forever!) I have found myself having to put the topic on hold for a week or two to write a draft for my Phil Science, Phil Language, and Ancient classes. I wish I were smarter, this would probably be a lot easier.
After reading several views about simplicity in scientific theories I have found Sober’s to be the most interesting and I find myself agreeing with him to a certain degree. Instead of trying to relate simplicity to the correctness of a theory, Sober has related simplicity to the informativeness of a theory, “The theory that I have been elaborating and defending can be said to justify the use of simplicity in hypothesis choice on the grounds that informativeness is one of our goals in choosing hypotheses and, according to the theory, simplicity is informativeness.” (Sober, Simplicity 1975 p. 161) What it means for a theory to be simple (according to Sober) has to do with how much information it gives us in relation to how many laws/axioms we begin with. I guess giving it in terms of inputs/outputs; simpler theories will produce more outputs with fewer inputs. This appears to have a very important difference when relating it to a notion of simplicity that comes from Popper or Quine. Popper and Quine believed that simple theories have a higher probability of being true, so simplicity and truthfulness are directly related. This way of looking at simplicity seems to give it an epistemic importance; we can get more information from simpler theories so our ability to apply the theory and make predictions will be better. The problem I see with Sober is that he tries to make this an ontological importance as well and I don’t quite see the connection. If the simpler theory is false then it will be giving information about the false theory, not any truths about the world.
Should we reject simplicity as a characteristic of a good theory? According to Alan Baker “Most philosophers believe that, other things being equal, simpler theories are better.” My guess is that simplicity is irrelevant when deciding whether a theory is good or not. I think this is especially true when considering theories from an ontological standpoint. If you can get a simpler theory of the world that leaves out objects of the world then that theory should be rejected. Of course, this notion is mentioned in Alan Baker’s quote, “other things being equal,” but it is hard to think of a situation where you have two competing theories that are equally accurate but one of them is simpler than the other. Say you have two different theories, T1 and T2. How is it the case that T1 is more complicated than T2 or vice versa? Well, if we consider Occam’s Razor
(OR) Entities are not to be multiplied beyond necessity. (Baker)
then the theory that has more entities is the more complicated theory. Let us consider T1 being the more complicated theory so that means there are more entities in T1 than T2. Do we reject T1? Well, what if the entities discussed in T1 are actually in the world? Well, it seems like accuracy would dictate that we choose T1. What if the entities discussed in T1 are not there? In that case it would appear that we should choose T2 (assuming it doesn’t talk about things that are not in the world). It would seem like simplicity drops out when taking an ontological view. When considering the situation from an epistemic view, maybe a simpler theory is more appealing to us (persons) but I don’t have a clear guess on that subject yet.
Baker, Alan, “Simplicity”, The Stanford Encyclopedia of Philosophy
