As eloquent as this manifesto is, it fails to actually address some of the arguments against tau. In 2.1, it points out that d/dx sin(x) = cos(x) only holds if

As eloquent as this manifesto is, it fails to actually address some of the arguments against tau. In 2.1, it points out that d/dx sin(x) = cos(x) only holds if x is in radians. This is key Once you switch to expressing x in diameterians or tau-radians (or whatever you'll call them), this identity falls apart: d/dx sin(x) = cos(x) / 2 d^2/dx^2 sin(x) = -sin(x) / 4 ... And so on. The trig functions lose their cyclical nature. (More explanation on wiki: http://en.wikipedia.org/wiki/Trigonometric_functions#The_significance_of_radians http://en.wikipedia.org/wiki/Trigonometric_functions#The_sig... ) I hate to be a Debbie Downer, but you can't ignore these things.