 For instance, Margolis argues that Aristotle's discussion of the principle of non-contradiction presupposes the changelessness of individual things rather than providing any proof of the alleged law.In Margolis's view non-contradiction applies to "sentential formulas" and not to "meaningful sentences", since discourse in use may always offset any seeming contradiction via re-interpretation, as is routinely done in science (for instance, in the case of the wave theory versus the corpuscular theory of light).In other words, there is no conceptual necessity to accept a strictly bivalent logic; our logics depend, in a deep sense, on what we pre-thinkingly take the real world to be like.