Two perceptions of `risk' tend to dominate leading conceptualizations of this term. The first perspective is largely held by government and the scientific community. Risk, in this view, is something that can be measured, observed, mapped and generally controlled. Under this perspective, planning is often perceived as playing a central scientific role in the achievement of this `management' task. The second perspective is a poststructuralist one where risk is a constructed concept. This article explores this perspective from the position that risk is a fear of the repressed, undecidable and unknown that haunts social reality, for it may spring up at any time to create adversity and misfortune. In this view, risk is inherently an ideological spectre responding to a lack of knowledge, uncertainty and/or inherent unknowability, which in turn induces society to crave and then seek to generate further constructs of certainty, even if these are mere fantasies and illusions that purport to control and overcome the unknown. In contrast to the scientific realist perspective of `manageable' risk, this article argues that planning often produces just such an ideological response. Further, it argues that a desire for certainty to offset the haunting of this risky future, no matter how illusionary, underlies and empowers planning's very ontological purpose. It concludes by proposing an alternative ontology for planning, which actively engages with change and the unexpected.