Nowhere does science meet philosophy more profoundly than in quantum physics. Intellectual excitement, and sometimes also frustration, is tangible in the thriving debates about what our best physics is telling us about the world. Much publicised conceptions of the 'many worlds' and 'pilot waves' of quantum physics represent radically different ways of making sense of the theoretical framework that revolutionised 20th century science, and there is no shortage of alternative ideas. It is undeniable that central notions of quantum theory — superposition, entanglement, spin, and the like — capture strange features of the physical world. But which features exactly? Many old controversies surrounding this question are still fiercely debated, fuelled by often unacknowledged presuppositions that are as much philosophical as they are scientific. The unabating uncertainty about what exactly quantum physics is telling us about the world also raises an important issue about the very nature of physics: what kind of knowledge does it provide? 

Science is often regarded as being in the pursuit of knowledge and understanding. Indeed, according to the Science Council, the very definition of science is “the pursuit of knowledge and understanding of the natural and social world following a systematic methodology based on evidence." This definition has its limitations, however, and reflecting on the kind of knowledge that quantum physics provides suggests a different, complementary way of appreciating the grand theoretical edifices of science. How grand? Well, ‘quantum physics’ encompasses a truly enormous set of specific theories, including those of particle physics with its celebrated discoveries of the Higgs boson, quarks and the like, and the image of reality they imbue us with.