Why do we need science in the first place? This is the first question we should ask in ascertaining a philosophy of science. The answer is already familiar to us. We need science because we have explanations about how the world works and we know many of them are wrong.If the explanation of physical phenomena were evidence in their appearance, as empiricism suggests, we would know things pretty easily. Science arises precisely because it is hard to explain the world. Or, more accurately, because it is hard for us to explain the world.
Deutsch writes about the scientific revolution being born out of a time where dogmatic, weak explanations gave way to critical search for strong, hard to vary explanations.
What does 'hard/easy to vary' mean?
People once accepted myths and these explanations were such that it was of no real consequence if you varied their details. For example, the ancient Greek myth explaining the weather stated that winter was caused by Hades, long ago, kidnapping the goddess of spring, Persephone. Persephone's mother negotiated a deal where Hades would let her go, but under the agreement that she would eat a magic seed that would compel her to still visit him once a year. This is fundamentally different to the tight explanations that we associate with science. Why a magic seed and not another kind of magic? This is a detail that could be changed. Likewise, it could be that her father made the deal. It could be that she visits once a year to get her revenge on Hades. Or he is obsessed and kidnaps her every year. They could even easily be different gods entirely.
Scientific explanations, are hard to vary.
When philosophy of science became prominent in the early 20th century it was in part to do with how impressed people were by science. There was an idea that it served some kind of noble function, and served it with unusual reliability. The philosophers were not interested because their passions lay with science, particularly, but because they wanted to know if there was anything philosophy could learn about itself. And indeed they were right. Science does serve a noble function. It is not just that we have expectations, and the world will occasional disagree with them by having things like stars not fall to the ground, science is important because we have a history of accepting our expectations and ignoring the problems with them. As Deutsch illuminates, science began when we stopped making it so easy to fool ourselves--when we began a trend of looking for problems and creating hard to vary explanations.
Karl Popper sums up why we need science:
“Science, one might be tempted to say, is nothing but enlightened and responsible common-sense—common-sense broadened by imaginative critical thinking. But it is more. It represents our wish to know, our hope of emancipating ourselves from ignorance of the expert, the narrow-mindedness of the specialist, or the fear of being proven wrong, or of being proved 'inexact', or having failed to prove or justify our case. And it includes the superstitious belief in the authority of science itself”
Most philosophies of science time and time again get this wrong. They treat science as almost obvious. Empiricists describe science as being something you can quite easily read in nature. Even more common is to treat scientific theories as easy to verify. It is a fundamental misunderstanding of what science is for: to challenge what we think is obvious about reality.