The axiomatic Method The axiomatic method involves replacing a coherent body of propositions (i.e. a mathematical theory) by a simpler collection of propositions (i.e. axioms). The axioms are designed[by whom?] so that the original body of propositions can be deduced from the axioms. http://en.wikipedia.org/wiki/Axiomatic_system Here we see that any system of propositions can be reduced or replaced by axioms. Langan refines the definition of reality as follows. Reality is the perceptual aggregate including (1) all scientific observations that ever were and ever will be, and (2) the entire abstract and/or cognitive explanatory infrastructure of perception. That is, reality consists of (1) perceptions, and (2) all relevant supporting structure. For example, if you see an apple fall from a tree, your perception of the apple qualifies as real by (1), while the law of gravity that caused the apple to fall qualifies as real by (2). http://ctmucommunity.org/wiki/Reality In Langan's view, reality, as the aggregate of perceptions, is therefore axiomatic.