BY the end of its 100-minute span, Testimonium has jigsawed into a Chinese Box with the act and art of witnessing at its heart.

The crafting spirits are core members of Chicago's Goat Island, the now-disbanded group revered worldwide for powerful,affecting work that boldly grounded physical performance in an intellectual mindset. Now flying under the name Every House Has a Door, director Lin Hixson, dramaturg Matthew Goulish and performer Bryan Saner have brought their shared rigour to bear on the poems of Charles Reznikioff (1894 - 1976) whose unfinished work, Testimony, drew on transcripts of American court cases heard between 1855 and 1915.

This isn't, however, a simple narration of shocking facts, primarily industrial accidents that smack of criminal negligence, criminal cases that suffer from police and judicial negligence. Saner's calm, unhistrionic delivery of details is just one element in an over-arching structure that connects the linear precision of geometry with a similar integrity of moral values. As movement and music - with Stephen Fiehn's businesslike activities creating a visual dimension and live band, Joan of Arc, searing the ears with visceral-lyrical songs - build a mult-dimensional rhythmic interplay on-stage, so the concept of what it is to "witness" takes on a wealth of possibilities. Reznikioff's work is never judgemental, nor is this Testimonium. Things happen; people see them, talk about them, even go into court and swear to them, and make that their "truth". We watch this intense, wonderfully considered and nuanced performance and we witness - what? I saw a challenge to complacency, a reminder for us to keep questioning what passes for truth - and a company that cares to think seriously about art as a witness to life.