Engineering POV makes sense, but Turing-completeness is well-defined in CS i.e. maths, and maths deals with unbuildable stuff all the time. You can't engineer a

Engineering POV makes sense, but Turing-completeness is well-defined in CS i.e. maths, and maths deals with unbuildable stuff all the time. You can't engineer a result into CS unless you prove your engineering in a mathematical fashion, e.g. the famous four colour theorem proof.