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

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In Defense of Taxonomic Monism: On What What There Is Does

Anna-Sofia Maurin

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 presupposition of scientific realism. It is meant to make scientific realism distinct from all those anti-realist accounts of science…which reduce the 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

• 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

Scientific realism as the solution to two problems…

A problem for metaphysics A problem for science

On what grounds can we justifiably make metaphysical/ontological claims about mind-independent reality? Answer: on SCIENTIFIC grounds How do we explain the fact that science has been, is, and continues to be successful, both when it comes to making predictions and retrodictions, etc.? Answer: With reference to our REALISM

Science as the window to the world

science

Mind-independent reality

Scientific Realism & Taxonomic Monism

1. The world has one unique mind-independent structure; 2. Scientific theories discover and map out the structure of mind- independent reality.

Trouble for the scientific realist?

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. What is the scientific realist to make of the classificatory practices in at least some parts of science? Phenetic Interbreeding Ecological Phylogenetic

Degree of similarity

• f phenotypic traits

Reproductive boundaries of actually or potentially interbreeding populations Ecological role or niche Speciation and Extinction (historical)

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Ways out?

Reductionism BUT…even if possible, what prevents the reduction-base from being i turn amenable to alternative mutually incompatible classifications? So much the worse for science! BUT…that arguably amounts to giving up on scientific realism.

Can you eat your cake and have it too?

What we need: A way to accept the classificatory practices of modern science while maintaining that science can teach us about the structure of mind- independent reality. To Charavartty this means that we should become Realist Taxonomic Pluralists!

First step: Make science informative again!

The mind-independent content of scientific descriptions is given by the properties used to describe the particulars involved. ”…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” Claim: Science is primarily concerned with picking out properties and property-structures and NOT natural kinds and natural kind structures; Science teaches us which properties there are, not which natural kinds there are!

Properties can be conventionally grouped in different ways to form different categories of particulars.

The first step explains scientific classificatory practice

Mind-independent reality

Mind independent reality contains properties x, y, z x, y, z can be usefully classified in ways A, B, C

Against going Ramseyan

”…arguably, any position is rendered nearly empty qua realism if it is compatible with the view that a scientific theory is true merely in virtue of there being some unobservables such that the observable consequences of the theory are true. I submit that if there is to be an account of Taxonomic Pluralism that is compatible with realism, it should yield more substantive knowledge of the unobservable.”

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 at liberty to determine what groupings of properties there are, in

• reality. Properties are not as far as empirical investigation would

appear to suggest, randomly distributed across spacetime. Rather, they are systematically sociable. “…while scientists are certainly free to label different patterns of coherence as constituting different structures of entities and processes, it is surely not up to them what patterns there are. The choice as to which we recognize is conventional, but the structures we recognize are not.”

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A Sociality-Based Pluralism

Mind independent reality contains properties x, y, z, … x, y, z can be usefully classified in ways A, B, C

A B C

”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 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.”

Monism or Pluralism?

Properties sociable Properties not sociable Metaphysical Taxonomic Pluralism Conventional Taxonomic Pluralism Structures conventional X X X Structure mind- independent X X

If the structures are conventional (and so mind-dependent), then irrespective of whether properties are sociable or not, Taxonomic Pluralism is NOT a thesis about the structure of mind-independent reality. If the structure is mind-independent because properties are inherently sociable, then even if we admit that our pragmatic interests may change and contradict one another, there is still just one unique structure underlying all classification.

Back where we started?

1. Given how science works, it cannot tell us about the natural kind structure of mind-independent reality; 2. Even if science can tell us about what natural kind structures there are, this is arguably not the sort of information the metaphysician is after; 3. According to Chakravartty, science can tell us which properties there are. 4. This means that he thinks that science can tell us that there is properties – to a metaphysician that claim is clearly underdetermined by scientific data. 5. But then what can science justifiably inform us about concerning mind-independent reality?

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.