Science: has it gone too far? This sounds like one of those vox-pop questions from The Day Today (readers who don't know what I'm talking about should click here). But if you follow these matters, you'll know that it's been the topic of a fractious recent debate among scientists and philosophers. The accusation – made, for example, in Curtis White's book The Science Delusion, and elsewhere – is that we're living in an era of rampant "scientism". This is a vague term that refers, broadly, to scientists overstepping their boundaries, applying scientific forms of thinking where they don’t apply.

The opposing case got a major boost this month from Steven Pinker's essay in The New Republic, entitled Science Is Not Your Enemy; scientism, he argued, was "more of a boo-word than a label for any coherent doctrine". The whole concept, he strongly implies, is a straw man, "equated with lunatic positions, such as that 'science is all that matters' or that 'scientists should be entrusted to solve all problems'. Nobody really thinks science can tell us how to live. ("When I hear people accused of scientism, they’re not trying to determine the moral law with particle accelerators," adds Scott Alexander at Slate Star Codex, echoing this point.) The reliably, um … forthright Chicago University evolutionary biologist Jerry Coyne calls scientism a "canard" – as evidenced by "the failure of 'scientism' critics to give examples of the sin."

Wow. Just wow. I don't know how to respond to this.

Harris is refreshingly upfront about his argument: the subtitle of his book is How Science Can Determine Human Values. It's a full-frontal assault on the Humean notion that you can't get an "ought" (a principle about how the world should be) from an "is" (a descriptive finding about how the world actually is). Neurobiology is changing all that, Harris insists. In principle, if not yet in practice, we'll be able to study – as a matter of scientific fact – which policies, laws and lifestyles lead to the greatest human wellbeing. Dictatorships can thus be shown to promote more misery and less happiness than democracies. Dodgy relativistic notions about, say, female genital mutilation being acceptable in certain cultural contexts, will collapse; science can demonstrate that FGM greatly reduces wellbeing for those who undergo it, and that's the end of the argument. Science can show us not just how the world is, but "what we should do and should want".