What Is Reality: Reviewing The Grand Design, III

After the general patterns established last chapter, I was surprised to see a change of pace in Chapter 3. One might get the impression that scientists drawing a dichotomy between natural and supernatural explanations are headed inexorably towards a declaration of scientism and a denigration of religion. That wasn’t the case here, well… at least not as explicitly as in some other books of similar nature. Of course, we’ve still got five chapters to go.

Though in Chapter 1 they declare “philosophy is dead,” something the authors call model-dependent realism turns out to be the key point of Chapter 3. They begin by summarizing the differences between philosophical realism – essentially the view that stuff exists objectively – and philosophical anti-realism – essentially the view that everything is a construct of mind, or the view that we would lack access to any objective reality should one exist. Seemingly well aware of the battles which rage between these two disciplines, the authors waste no time presenting model-dependent realism’s strength, and they are also poignantly honest about it:

Another problem that model-dependent realism solves, or at least avoids, is the meaning of existence. [p47]

Under this view, there is no point to have arguments over “what really exists.” Rather, utility lies in the usefulness of any given model, it’s apparent degree of correspondence with reality. The authors use the analogy of a goldfish in a round bowl, noting that it would still be possible for the goldfish to come up with a model that accurately described and accounted for the events they saw. Though the goldfish would have a distorted perception of reality, this fact wouldn’t preclude their ability to construct useful models.

It’s quite an interesting idea, when you think about it. After a minute or so of contemplating this, I came to the conclusion that even if everything science described was a distorted reality, our models could still be useful for making accurate predictions. Whether or not our best theories actually describe actuality depends on the shape of the bowl.

Instead of approaching Genesis from a virulent Sam Harris or Richard Dawkins perspective, the authors simply refer to it as a different model. Of course, they don’t imply that it’s on equal par with QM, but it’s refreshing to get the feeling that the book might not be framed in the atheist vs. theist context that’s become so pervasive in intellectual discourse these days.

The authors share their criteria for good models:

A model is a good model if it:

1. Is elegant
2. Contains few arbitrary or adjustable elements
3. Agrees with and explains all existing observations
4. Makes detailed predictions about future observations that can disprove or falsify the model if they are not borne out. [p51]

I liked that the authors were quick to concede the inherent subjectivity at play here. For example, they concede that “elegance” is a matter of subjectivity. They spend the next few pages discussing examples of models that gave way to observation: Aristotle’s four-element theory, which predicted that heavier objects should fall faster; and static-universe theory, which predicted observations in support of a fixed universe. Galileo and Hubble produced observations that directly challenged these models, and when the modifications needed to salvage them became to baroque, they ceded to observation. That’s science.

The next key concept the authors introduce is that,

With each theory or model, our concepts of reality and of the fundamental constituents of the universe have changed. [p54]

This is an oft-repeated premise of those favorable to scientific anti-realism [and I am not putting the authors in that category, either]. I often think of this fact, and wonder how many of our current models will be found wanting in the years to come. Often, science can reconcile apparently contradictory claims. The authors use Newton’s rings to demonstrate this. Newton described light as corpuscular, but that theory couldn’t explain what he observed while illuminating a flat reflecting plate with light of a single color. The “rings” seen are difficult to explain on corpuscular accounts, yet, seem easily explainable via the phenomenon of interference – which would imply that light retains wave-like properties.

Building on this same example, the authors note that many nineteenth-century scientists saw Newton’s rings as disproving corpuscular theory. However, sometimes the pendulum swings too far in the other direction. Einstein’s twentieth-century demonstration of the photoelectric effect seemed to confirm the corpuscular theory just as much as Newton’s rings seemed to confirm the wave theory. Today, we simply say that light acts both as corpuscle and wave.

The authors use these examples to further demonstrate the concept of model-dependent realism:

Dualities like this – situations in which two very different theories accurately describe the same phenomenon – are consistent with model-dependent realism. Each theory can describe and explain certain properties, and neither theory can be said to be better or more real than the other. [p54]

All of this makes me eagerly await their explanation of M-theory, but that’s Chapter 5.

Chapter 4 introduces the concept of alternative histories, and we’ll pick up there next time.