Sunday, July 11, 2010

The "no miracles" argument against scientific realism

By "no miracles" I'm referring to Hilary Putnam's observation:

“The positive argument for realism is that it is the only philosophy that doesn't make the success of science a miracle”

Let's assume that our best scientific theories tell us something true about the way the world *really* is, in an ontological sense. And further, for simplicity, let's assume a deterministic interpretation of those theories.

In this view, the universe as we know it began ~13.7 billion years ago. We'll set aside any questions about what, if anything, preceded the first instant and just draw a line there and call that our "initial state".

Given the specifics of that initial state, plus the particular causal laws of physics that we have, the universe can only evolve along one path. The state of the universe at this moment is entirely determined by two, and only two, things: its initial state and its casual laws.

But this means that the development of our scientific theories *about* the universe was also entirely determined by the initial state of the universe and it's causal laws. Our discovery of the true nature of the universe has to have been "baked into" the structure of the universe in its first instant.

By comparison, how many sets of possible initial states plus causal laws are there that would give rise to conscious entities who develop *false* scientific theories about their universe? It seems to me that this set of "deceptive" universes is likely much larger than the set of "honest" universes.

What would make universes with honest initial conditions + causal laws more probable than deceptive ones? For every honest universe it would seem possible to have an infinite number of deceptive universes that are the equivalent of "The Matrix" - they give rise to conscious entities who have convincing but incorrect beliefs about how their universe really is. These entities' beliefs are based on perceptions that are only illusions, or simulations (naturally occurring or intelligently designed), or hallucinations, or dreams.

It seems to me that it would be a bit of a miracle if it turned out that we lived in a universe whose initial state and causal laws were such that they gave rise to conscious entities whose beliefs about their universe were true beliefs.

A similar argument can also be made if we choose an indeterministic interpretation of our best scientific theories (e.g., quantum mechanics), though it involves a few extra steps.

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