Can we derive oat from whizz?

Hume:

In every system of morality, which I have hitherto met with, I have always remarked, that the author proceeds for some time in the ordinary ways of reasoning, and establishes the being of a God, or makes observations concerning human affairs; when all of a sudden I am surprised to find, that instead of the usual copulations of propositions, is, and is not, I meet with no proposition that is not connected with an ought, or an ought not. This change is imperceptible; but is however, of the last consequence.

Popper:

Perhaps the simplest and most important point about  ethics is purely logical. I mean the impossibility to derive non-tautological ethical rules-imperatives;  principles of  policy;  aims;  or  however  we  may describe them-from  statements  of  facts.  Only  if  this  fundamental logical position is realized can we begin to formulate the real  problems
of moral philosophy, and to appreciate their difficulty

Searle:

1. Jones uttered the words “I hereby promise to pay you, Smith, five dollars”

2. Jones promised to pay Smith five dollars.

3. Jones placed himself under the obligation to pay Smith five dollars.

4. Jones is under the obligation to pay Smith five dollars.

5. Jones ought to pay Smith five dollars.

etc.

But, interestingly, Kuhn: