Realism and Anti-Realism

Realism and Anti-Realism

Universals

Universals

We use universal terms "dogs" "time" "causation" "human" etc. all the time and our language leads us to attribute causal properties to them but we never experience them directly.

So, are (some) universals real entities or are they merely labels we construct out of convenience?

Some Theories

Realism: Universals exist independently of us. (Platonism)

Moderate realism: Universals exist as they are instantiated in particulars

Nominalist: Universal terms are simply names for e.g. bundles of sense data (Hume/ Russell)

Anti-Realism: Universals serve a purpose in relation to our explanatory goals.

Why Does It Matter?

Science is our best bet at understanding the world and it relies heavily on postulating theoretical entities i.e. universals

Most scientists are scientific realists: they believe that the task of scientific enquiry is to reveal a mind-independent reality.

If realism is false, then they are radically misguided about that they are doing and so are we insofar as we follow

them.

Case Study: The Species Problem

The Species Problem

'Species' is a key theoretical term in biology

However, there is remarkably little consistency on how to define 'a species'/

There are about 37 different ways of doing speciation, each of them respectable, empirically fruitful and inconsistent.

Darwin himself was agnostic about the

reality of species despite penning a rather well-known work on their origins.

Species as Individuals

"Species" means a reproductively isolated breeding population

Problem: most species are asexual.

Also: whether some sexual species reproduce depends upon ecology.

Scientific Realism

Nominalism

When applied to science, nominalism would suggest that theoretical entities are posits which explain past observations and predict future ones.

This ignores the fact that much science has very little to do with observation

The Quine-Duhem thesis

Einstein: "The theory determines what counts as an observation"

Therefore nominalism doesn't do justice to the role of theoretical entities in science.

Anti-Realism

Natural Kinds

What happens when theoretical terms change?

E.g. phlogiston vs. oxygen

The realist would suggest that we get closer to the truth

The anti-realist would argue that one term is more useful than another given a whole series of other explanatory commitments.

Science aims at empirical adequacy not truth (in any metaphysical sense)

The traditional view of science is that it is in the business of uncovering laws of nature.

Do The Laws of Physics Lie?

Phenomenological laws cover what can in principle be observed.

Fundamental laws purport to explain what can be observed

However, "the cost of explanatory power is descriptive adequacy. [r]eally powerful explanatory laws of the sort found in theoretical physics do not state the truth."

Nancy Cartwright (1983) How The Laws of Physics Lie Cambridge: CUP. p.3

A law quantifies across classes of objects

not individual objects.

Newton's Law of Gravity

A particle attracts every other particle in the universe using a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.

This is supposedly true of every particle in the universe.