He argues in the "Novum Organum" that our only hope for building true knowledge is through this careful method. Old knowledge-building methods were often not based in facts, but on broad, ill-proven deductions and metaphysical conjecture. Even when theories were based in fact, they were often broad generalisations and/or abstractions from few instances of casually gathered observations. Using Bacon's process, man could start fresh, setting aside old superstitions, over-generalisations, and traditional (often unproven) "facts". Researchers could slowly but accurately build an essential base of knowledge from the ground up. Describing then-existing knowledge, Bacon claims: