9.1 Engineers are against τ
He has forgotten about the practical application of mathematics - engineering. Tau is already one of the most important symbols in mechanical engineering as it denotes shear stress. Additionally the ratio of diameter to circumference is very important when we work with bars of material or pipes. We tend not to purchase these by the radius. Perhaps a little more thought and debate are required in this matter before we start a revolution.
It should be mentioned that the Tau Manifesto does give a good argument for using the symbol τ. However, we question whether the constant τ=2π is actually needed in mathematics.
Uhhh... nice try? I'm an electrical engineer and τ is definitely preferable to π in every instance I can think of, even if the symbol is also used for RC time constants. This quote is just an argument against the symbol τ, anyway, not against the concept. Lots of symbols have multiple meanings in engineering, including π.
2π comes up constantly in engineering, especially in anything involving frequency. Inductance is 2πfL, cutoff frequency is [tex]1 \over 2 \pi R C[/tex], 2π is everywhere in Fourier transforms, etc. It's always struck me as odd, but now I know why: π is wrong.
Most of the arguments in this manifesto were pre-emptively addressed by the Tau Manifesto, especially all the variants of "π is natural for area", so I'm not sure why someone bothered to write them out.