> a machine-executable model would be unhelpful in determining whether Jaffa Cakes should be taxed for VAT as biscuits, or exempt as cakes. You can have these

> a machine-executable model would be unhelpful in determining whether Jaffa Cakes should be taxed for VAT as biscuits, or exempt as cakes. You can have these definitions remain vague and still have an algorithm that is well defined over pre-labeled data. The purely mechanical steps based on arithmetic could (and should!) be defined as machine-parseable code or formulas.