This is another Canon of Construction which holds that each claim should be presumed to differ in scope from every other claim in the patent. The underlying assumption here is that an applicant wouldn't intentionally draft two claims that covered, in different words, the exact same subject matter. Note that this doctrine of claim differentiation is not absolute, however, for sometimes the only reasonable interpretation of a claim is one that makes it redundant. See Kraft Foods, Inc. v. International Trading Co., 203 F.3d 1362, 1368 (Fed. Cir. 2000).