The power of words is a wonder, and language perhaps our greatest skill. Yet the gap between the sound of a bell and its description is huge. Are the limits to language so profound that the big questions of science and philosophy are beyond us? Or can everything be said if we try hard enough?

In this issue of IAI News we interrogate the limits of knowledge. All human knowledge is conceived and expressed through language, argues author Joanna Kavenna. But language is radically limited. We can never simply step outside the limits of language. The realm of eternal truths is ultimately beyond us.

Given the radical contingency of linguistic truth, how can we understand and effect changes in the world? Can we hope to diagnose illness accurately or is all knowledge fantasy? Consultant psychiatrist Mark Salter outlines his new theory of psychiatry after postmodernism.

Elsewhere in this issue, we explore three very different limits: the limits of science, the limits of leadership, and the limits of free speech. Cosmologist George Ellis asks: will science uncover every mystery in the universe or are there some questions best left to philosophers? Meanwhile, author and CEO Margaret Heffernan warns of the limits of leadership. The hero and the genius are both fantasies, she says. We need a new model of collective decision-making. And, in light of Charlie Hebdo, philosopher Brian Klug asks: do we have a right to offend? Or do even fundamental human rights have their limits?

Finally, activist and writer Beatrix Campbell expounds the new sexual settlement. Despite feminism’s many triumphs, she says, it has not won. Nor can it in the neoliberal world order.