Stephen Hawking (SH) is one of the greatest scientists ever. He is a cosmologist, particularly well-known for his work on black holes. The book THE GRAND DESIGN, published last year by Hawking and Mlodinow (H&M), has a touch of finality, as if an unusually sharp scientific brain has finally succeeded in finding rational answers to the basic questions about ourselves and about our universe. I have summarized the main ideas of this book in an online article. Here I give a glimpse of that work by discussing the meaning of 'reality'.
There are several umbrella words like ‘consciousness’, ‘reality’, etc., which have never been defined rigorously and unambiguously. H&M argue that we can only have 'model-dependent reality', and that any other notion of reality is meaningless.
Does an object exist when we are not viewing it? Suppose there are two opposite models or theories for answering this question (and indeed there are!). Which model of ‘reality’ is better? Naturally the one which is simpler and more successful in terms of its predicted consequences. If a model makes my head spin and entangles me in a web of crazy complications and contradictory conclusions, I would rather stay away from it. This is where materialism wins hands down. The materialistic model is that the object exists even when nobody is observing it. This model is far more successful in explaining ‘reality’ than the opposite model. And we can do no better than build models of whatever there is to understand and explain.
In fact, we adopt this approach in science all the time. There is no point in going into the question of what is absolute and unique ‘reality’. There can only be a model-dependent reality. We can only build models and theories, and we accept those which are most successful in explaining what we humans observe collectively. I said ‘most successful’. Quantum mechanics is an example of what that means. In spite of being so crazily counter-intuitive, it is the most successful and the most repeatedly tested theory ever propounded.
A model is a good model if: it is elegant; it contains few arbitrary or adjustable parameters; it agrees with and explains all the existing observations; and it makes detailed and falsifiable predictions.