This is because the book misses out a whole chunk of philosophy of science in favour of dedicating the second half to 'what science means for us', which primarily seems to be more a summary of some areas of soft science rather than true philosophy. We have some great material in the first half on what science is and on the work of the terrible twins Popper and Kuhn (of whom more in the moment), but I was left wanting so much more. What came after Kuhn (whose work is 50 years old)? We only get a few passing comments. There is nothing about peer review. Nothing about fraud in science. Nothing about the relationship of maths and science - in fact there was so much more philosophising I would have loved to have read about.
What there was proved excellent. I was vaguely familiar with the two big names in the philosophy of science, but only at a headline level. I knew, for instance, that Karl Popper's ideas, while still widely supported by scientists, are frowned on by many in philosophy of science - but I didn't know why. In a nutshell it's because Popper took things too far, not just talking about scientific theories being falsifiable, which most find acceptable, but going on to the say the process of inductive reasoning, so important to science, isn't valid - which no scientist can honestly find acceptable.
Similarly, while I had got a vague idea of Thomas Kuhn and his paradigm shifts, like everyone else except philosophers I wasn't really sure what a paradigm was - apparently Kuhn used the term as a kind of definitive exemplar driven change rather than a traditional revolution. I also wasn't aware of Kuhn's rather nutty ideas that taking a new scientific view didn't just change the view, but changed the actual universe. Really.
There were still points I'd disagree with. Lewens dismisses Popper entirely because of his anti-induction views, but doesn't say what's wrong with the apparently very sensible Popper Lite approach, with appropriate recognition that one experiment doesn't make a falsification isn't acceptable. Similarly but in the opposite vein, he gives in far too easily to Kuhn's idea on changing the universe, taking the example of the subjective nature of colour as showing that the way we look at things truly does alter reality. Well, no it doesn't. A flower is giving off exactly the same photons however you look at it - it's the interpretation that changes, not the universe itself. But I don't mind this - argument is the whole point of philosophy and why it's far more fun than the grumps like Stephen Hawking who claim we don't need it any more seem to realise.
So an excellent start first half to a book that I think all scientists and those with a true interest in science should read. But I just wish that second half had filled in those missing bits rather than trying to be a mini-popular science book with a touch of philosophical justification in its own right.
Review by Brian Clegg