A "demand" is a determination that derives from a perceived (or felt) need, want, or desire for the purpose of narrowing or closing the gap between a perception an observed situation (what is) and a preference or value (what ought to be). Basic demands are usually for resource access, better living conditions, physical safety, and security, all of which are generally considered under the rubric of utility by economists; while economists consider demand as the "ability to purchase", lateral pressure theory makes no such assumption. To meet demands—and to close the gap between the "is" and the "ought to be" and possibly approach or establish a "preferred condition"—an individuals and societies must possess the required "capabilities".