Science is not a ‘body of knowledge’ – it’s a dynamic, ongoing reconfiguration of knowledge and must be free to change ... each scientific discipline is governed by an accepted set of theories and metaphysical assumptions, within which normal science operates. Periodically, when this rather humdrum ‘puzzle solving’ leads to results that are inconsistent with the regnant perspective, there follows a disruptive, exciting period of ‘scientific revolution’, after which a new paradigm is instituted and normal science can operate once more. ... When Newton said: ‘If I have seen farther, it is by standing on the shoulders of giants’, he wasn’t merely being modest; rather he was emphasising the extent to which science is cumulative, mostly building on past achievements rather than making quantum leaps. ... the accumulation process generates not just something more, but often something altogether new. Sometimes the new involves the literal discovery of something which hadn’t previously been known (electrons, general relativity, Homo naledi). At least as important, however, are conceptual novelties, changes in the ways that people understand – and often misunderstand – the material world: their operating paradigms. ... The world’s factual details are in continual Heraclitean flux, but the basic rules and patterns underlying these changes in the physical and biological world are themselves constant. ... Our insights, however, are always ‘evolving’. ... Science is a process, which, unlike ideology, is distinguished by intellectual flexibility, by a graceful, grateful (albeit sometimes grudging) acceptance of the need to change our minds, as our understanding of the world evolves. Most people aren’t revolutionaries, scientific or otherwise. But anyone aspiring to be well-informed needs to understand not only the most important scientific findings, but also their provisional nature, and the need to avoid hardening of the categories: to know when it is time to lose an existing paradigm and replace it with a new one. ... Holding still is exactly what science won’t do.