If origins are as complex and perturbing as Derrida suggests, then we might ask of the current anthropic environmental predicament: what kind of planet is it that gives birth to a creature capable of doing such things? Biological life may be at its liveliest along the earth's sutures and fault-lines. But so too is fire. If humans are a fire species, then this is a fire planet. From the point of view of a ‘speculative geophysics’, our combustive habits may say at least as much about the deep-seated role of fire in welding together a fractious and differentiated planet as they do about any aberration on our own part.