The widespread philosophical view is that reductionism in the sciences is a dead view and perhaps slightly distasteful to boot. As I outlined in an earlier post, the received view assumes that “reductionism” is semantic, or Nagelian, reduction. The goal of such semantic reduction was to show that higher sciences are dispensable, leading Dennett to label it “greedy” reductionism, and that there are no higher levels in nature.
I earlier suggested scientific reductionist like Weinberg, Crick or E.O. Wilson, have different views from such greedy reductionism. In this post, I sketch my theoretical reconstruction of these novel views and show why the differences from semantic reduction matter a great deal. Rather than doing away with them, scientific reductionists like Weinberg seek to provide the best account of higher sciences and higher levels in nature. As a result, I outline why scientific reductionism avoids the famous philosophical objections to “reduction” and looks like a very live, and challenging, form of reductionism in the sciences.
Engaging compositional explanation and its features shows its worth in a couple of ways when seeking to understand scientific reductionism. To start, we can appreciate the most widely held, opposing, view in the sciences (and philosophy). Within the domains of particular sciences, we use intra-level causal explanations to understand specific phenomena using other entities at this level. But the sciences then go on to explain the entities used in such explanations through compositional explanations positing compositional relations to entities at lower levels. Putting together the apparent commitments of both intra-level causal, and inter-level compositional, explanations we have a picture of nature with many levels of determinative entities which are all horizontally determinative by producing various events at their own levels, but where we also have vertical relations of determination flowing upwards in compositional relations from the lower to higher level entities posited in inter-level explanations.
Adapting Sellars (1963a)’s famous terminology, the result is what we may term the ‘Scientifically Manifest Image’ because it is the picture of nature manifest in our scientific accounts and it is unsurprisingly widely endorsed in the sciences. The Scientifically Manifest Image also plausibly underlies the reigning ‘non-reductive physicalism’ in philosophy that is ‘physicalist’ by taking all entities to be composed and ‘non-reductive’ in accepting composed entities are nonetheless still determinative at their own levels.
Appreciating the Scientifically Manifest Image is important because it is the main target of scientific reductionism that claims to offer a better account of the import of compositional explanations and hence the best account of both the structure of nature and the sciences that study it. Crucially, the scientific reductionist accepts the descriptive account of compositional explanations, and compositional notions, outlined in the last post, but then offers arguments that putatively show that these concepts lead to a starkly different picture of nature and the sciences than that offered by the Scientifically Manifest Image.
Utilizing my framework for composition, I reconstruct the ontological parsimony reasoning using compositional concepts that the scientific reductionist plausibly uses to defend their emblematic claim that ‘Wholes are nothing but their parts’. Initially, I focus on the simplest of version of such reasoning, in what I term the ‘Argument from Composition’, that is based solely upon the successful application of compositional concepts in some scientific case. Given the nature of composition, rather than explaining by positing determinative composed and component entities, the reductionist concludes we can instead explain everything at the higher and lower levels equally well using the existence of component entities alone. But, given this sub-conclusion, applying the Parsimony Principle the scientific reductionist further concludes that we should only accept that component entities are either the only determinative, or even existent, entities in a case of compositional explanation.
The scientific reductionist’s picture of nature, which I term ‘Fundamentalism’, takes there to only be one level of determinative entities in any case of compositional explanation, in the relevant components. However, I use my account of composition to highlight why Fundamentalism is not committed to the hackneyed “Atoms-in-the-Void” picture so often ascribed to reductionism. Crucially, I highlight why, given her focus on compositional explanation, the scientific reductionist is committed to what I term a ‘Collectivist Ontology’ encompassing isolated components and also collective phenomena like collectives of inter-related individuals. For at the base of compositional explanations we always find collectives of entities – i.e. inter-related individuals and processes – and so her parsimony reasoning commits the Fundamentalist to such collective phenomena.
Most importantly, I outline how the Collectivist Ontology allows the scientific reductionist to endorse a sophisticated account of the macro-world, and its levels, encompassing multiple realization, qualitative emergence and the fact that ‘More is Different’, albeit on her own terms. And I consequently detail why the scientific reductionist’s Fundamentalist position endorses both a macro-world and indispensable higher sciences that study it – just not the treatment of these phenomena implied by the Scientifically Manifest Image.
Scientific reductionism consequently accepts that higher sciences are in principle indispensable because I show that under the reductionist’s Collectivist Ontology the predicates of higher sciences are needed to express many of the truths about nature concerning collective phenomena. I thus conclude that Weinberg is right to press what he aptly terms the “compromising” nature of contemporary scientific reductionism (Weinberg (2001), p.13), since my work establishes that this position is best understood as a combination of a thorough-going ontological reductionism and an equally robust semantic anti-reductionism that takes higher sciences to be significant and indispensable.
My theoretical framework for scientific reductionism thus highlights its many contrasts with the philosophically influential semantic model of reduction. For the Fundamentalist framework of scientific reductionism conflicts with all four commitments of semantic reduction I highlighted in an earlier post, by (i*) accepting the central role in the sciences of compositional explanations and their compositional concepts; (ii*) pressing an ontological form of reduction; (iii*) accepting the in principle indispensability of higher sciences, and (iv*) embracing a complex macro-world where ‘More is Different’. And I consequently show that the famous philosophical objections to semantic reduction, utilizing the features of compositional explanations and their compositional concepts, all fail against scientific reductionism that accepts the premises and conclusions of these critiques, albeit on its own terms.
Two main arguments are taken to have dispatched “reductionism”: the Multiple Realization Argument and the Argument from Predicate Indispensability. Let me briefly examine their impact on scientific reductionism.
With regard to the Multiple Realization Argument, Fundamentalism is driven by parsimony arguments using compositional notions like realization, so although multiple realization undercuts the identities needed for semantic reduction it provides the engine of the Fundamentalist’s ontological reductionism.
Turning to the Predicate Indispensability Argument, it shows higher predicates are indispensable – hence undermining greedy semantic reduction which entails such predicates are dispensable. But Fundamentalism endorses the in principle indispensability of higher sciences and their predicates. Consequently, Fundamentalism accepts the conclusion of the Predicate Indispensability Argument and is again untouched by it.
The last generation of philosophers of science, like Fodor and Kitcher, were right that semantic reduction is a dead view because of the features of compositional explanations and their compositional notions like “realization”. But the wager of these writers was that their arguments showed “reductionism” more widely is also consequently a dead position. Unfortunately, that wager did not succeed. I show that scientific reductionism, contrary to the received wisdom in philosophy, is very much a live position.
The pressing question that confronts us is one Weinberg has long emphasized: Why are we not all scientific reductionists now? Since the philosophical critiques of “reduction” only engage semantic reduction, leaving scientific reductionism untouched, I turn in Part III of the book to whether work on “emergence” might help to assess the viability of Fundamentalism. I look at scientific emergentism in the next post.