Doris Salcedo's work Shibboleth 2007 was a long snaking fissure that ran the vast length of the Turbine Hall, as if striking to the very foundations of the museum. Something similar might be said of the concept that underpins the piece.
The word 'shibboleth' refers back to an incident in the Bible, which describes how the Ephraimites, attempting to flee across the river Jordan, were stopped by their enemies, the Gileadites. As their dialect did not include a 'sh' sound, those who could not say the word 'shibboleth' were captured and executed. A shibboleth is therefore a token of power: the power to judge, reject and kill. What might it mean to refer to such violence in a museum of modern art?
For Salcedo, the crack represents a history of racism, running parallel to the history of modernity; a stand off between rich and poor, northern and southern hemispheres. She invites us to look down into it, and to confront discomforting truths about our world.