No, war does not have to be inevitable. I agree with Horgan that war is not an innate biological function, rather an invention. My belief, that war is a social invention, is based upon the array of unpleasant emotions associated with the competition for human needs on a planet with finite resources. But as Horgan and Steven Pinker and others have noted, as our civilization evolves, we have become enlightened to ways in which we can organize our society so that competition need not involve lethal human interaction. As our civilization grows more enlightened to methods of peaceful organization and institutionalization war will continue to decline.