2012-08-26 What is scientific realism? The metaphysical - PDF document

2012-08-26 What is scientific realism? The metaphysical stance…asserts that the world has a definite and mind- independent natural kind structure … [this] thesis is a basic philosophical In Defense of Taxonomic Monism: On presupposition of scientific realism. It is meant to make scientific realism distinct from all those anti-realist accounts of science…which reduce the What What There Is Does content of the world to whatever gets licensed by a set of epistemic practices and conditions. In particular the metaphysical stance implies that if the unobservable natural kinds posited by theories exist at all, they exist independently of humans’ ability to know, verify, recognize, that they Anna-Sofia Maurin do. Instead of projecting a structure onto the world, scientific theories, and scientific theorizing in general, discover and map out an already structured and mind-independent world … this metaphysical thesis is prerequisite to any meaningful defense of scientific realism. S. Psillos 1999: xix-xx Science as the window to the world Scientific realism as the solution to two problems… A problem for metaphysics A problem for science Mind-independent science How do we explain the fact that science On what grounds can we justifiably make reality has been, is, and continues to be metaphysical/ontological claims about successful, both when it comes to making mind-independent reality? predictions and retrodictions, etc.? Answer: on SCIENTIFIC grounds Answer: With reference to our REALISM Trouble for the scientific realist? Scientific Realism & Taxonomic Monism Taxonomic pluralism: In e.g. biology; ”Species” is codified in four different ways, where each serves a different scientific end, and neither can arguably be mapped onto any of the others. 1. The world has one unique mind-independent structure; Phenetic Interbreeding Ecological Phylogenetic 2. Scientific theories discover and map out the structure of mind- Degree of similarity Reproductive Ecological role or Speciation and independent reality. of phenotypic traits boundaries of niche Extinction (historical) actually or potentially interbreeding populations What is the scientific realist to make of the classificatory practices in at least some parts of science? 1

2012-08-26 Ways out? Can you eat your cake and have it too? What we need: Reductionism A way to accept the classificatory practices of modern science while maintaining that science can teach us about the structure of mind- BUT…even if possible, what prevents the reduction-base from independent reality. being i turn amenable to alternative mutually incompatible classifications? To Charavartty this means that we should become Realist Taxonomic Pluralists! So much the worse for science! BUT…that arguably amounts to giving up on scientific realism. First step: Make science informative again! The first step explains scientific classificatory practice The mind-independent content of scientific descriptions is given by the Properties can be conventionally grouped in different ways to properties used to describe the particulars involved. form different categories of particulars. ”…we learn that bodies with charge, in virtue of having this property, Mind-independent reality exhibit certain characteristic behaviors involving electromagnetic Mind independent reality contains properties x, y, z forces; in virtue of having the disposition to donate a proton or accept an electron pair, acidic substances exhibit certain characteritic behaviors when brought into contact with alkaline substances” Claim: Science is primarily concerned with picking out properties and property-structures and NOT natural kinds and natural kind structures; x, y, z can be usefully Science teaches us which properties there are, not which natural kinds classified in ways A, B, C there are! Against going Ramseyan Adding flesh to the Ramseyan bones Though scientists are at liberty to call different groupings of properties kinds as best suits various and different scientific needs, they are not ”…arguably, any position is rendered nearly empty qua at liberty to determine what groupings of properties there are, in realism if it is compatible with the view that a scientific reality. Properties are not as far as empirical investigation would appear to suggest, randomly distributed across spacetime. Rather, they theory is true merely in virtue of there being some are systematically sociable. unobservables such that the observable consequences of the theory are true. I submit that if there is to be an “…while scientists are certainly free to label different patterns of account of Taxonomic Pluralism that is compatible with coherence as constituting different structures of entities and realism, it should yield more substantive knowledge of the processes, it is surely not up to them what patterns there are . The unobservable.” choice as to which we recognize is conventional, but the structures we recognize are not.” 2

2012-08-26 A Sociality-Based Pluralism ”There is an important feature of what realists take to be mind- independent reality that is not captured by the notion that the dispositions conferred by causal properties account for the regular behaviours of things. Properties or property instances, are not the sorts of thing that come randomly distributed across space-time. They are systematically ”sociable”. They ”like” each other’s company… It is C this fact that one captures with talk about natural kinds and this feature of reality surely has a place in the ontology of scientific realism.” Mind independent reality contains properties x, y, z, … B x, y, z can be usefully classified in ways A, B, C A Monism or Pluralism? Back where we started? 1. Given how science works, it cannot tell us about the natural kind Properties Properties not Metaphysical Conventional sociable sociable Taxonomic Taxonomic structure of mind-independent reality; Pluralism Pluralism 2. Even if science can tell us about what natural kind structure s there Structures X X X are, this is arguably not the sort of information the metaphysician conventional Structure is after; mind- X X independent 3. According to Chakravartty, science can tell us which properties there are. If the structures are conventional (and so mind-dependent) , then irrespective of 4. This means that he thinks that science can tell us that there is whether properties are sociable or not, Taxonomic Pluralism is NOT a thesis about the properties – to a metaphysician that claim is clearly structure of mind-independent reality. underdetermined by scientific data. If the structure is mind-independent because properties are inherently sociable, then 5. But then what can science justifiably inform us about concerning even if we admit that our pragmatic interests may change and contradict one another, mind-independent reality? there is still just one unique structure underlying all classification. How to be humble AND bold ”…we learn that bodies with charge, in virtue of having this property, exhibit certain characteristic behaviors involving electromagnetic forces ; in virtue of having the disposition to donate a proton or accept an electron pair, acidic substances exhibit certain characteritic behaviors when brought into contact with alkaline substances” 1. Science can tell us what whatever there is does. 2. Metaphysics can furnish actors suitable for those roles 3. What those roles are is a scientific, not a metaphysical question. 4. Who can best play those roles is a metaphysical, not a scientific question. 3