One of the four requirements for well-formed goals is that you must know what you will hear, feel, see, taste and smell when you reach your goal. In other words, we want the results of NLP to be sensible. That means both smart and perceptible.
The proof of a prescription. – In general, the validity or invalidity of a prescription – a prescription for baking bread, for example – is demonstrated by whether or not the result it promises is achieved, always presupposing it is carried out correctly. It is otherwise now with moral prescriptions: for here the results are either invisible or indistinct. These prescriptions rest on hypotheses of the smallest possible scientific value which can be neither demonstrated nor refuted from their results: – but formerly, when the sciences were at their rude beginnings and very little was required for a thing to be regarded as demonstrated – formerly, the validity or invalidity of a prescription of morality was determined in the same way as we now determine that of any other prescription: by indicating whether or not it has succeeded in doing what it promised. If the natives of Russian America have the prescription: you shall not throw an animal bone into the fire or give it to the dogs – its validity is demonstrated with: ‘ if you do so you will have no luck in hunting’. But one has almost always in some sense ‘no luck in hunting’; it is not easy to refute the validity of the prescription in this direction, especially when a community and not an individual is regarded as suffering the punishment; some circumstance will always appear which seems to confirm the prescription.
Daybreak paragraph 24