Suppose libertarians could prove that durable, unqualified private property rights could be created through 'original acquisition' of unowned resources in a state of nature. Such a proof would cast serious doubt on the legitimacy of the modern state. It could also render the approach to property rights that I favour irrelevant. I argue here that none of the familiar Lockean-libertarian arguments for a strong natural right to acquisition succeed, and that any successful argument for grounding a right to acquire would (...) have to use my favoured approach to property rights - the 'vector-sum' approach. I conclude with some doubts about original acquisition theory and natural property rights. (shrink)