Fact Value Distinction

Me:

...The second point confuses me: is it a value judgment to say no ought from is, or is it, for some at least, a pure question of logical entailment? 

I'd think there's a difference between saying in one case: 

person A is drowning, we therefore ought to save him;

and in another case: 

Person A is drowning, but that doesn't entail our obligation to save him.

The first is an assertion of a logical consequence as a moral imperative. 

The second is a judgment or argument about whether as a matter of logic that consequence follows.

Does that difference make sense to you? 

Him, brilliant as usual:

....I don't think the fact value distinction is actually a rule derived from logic. None of the classic logicians, like Aristotle, used it.

Rather, as I understand it, it is a distinction drawn first by the empiricists (like Hume), and then more recently by behaviourists, like Skinner, and  stems from their view that a statement of fact and a judgment about value are different orders of statement.  

For them, statements of fact are the only reliable ones, because facts are observable,  verifiable and can be replicated in laboratories, etc.  Judgments about good and bad are, for them, none of those things. They are opinions, feelings, subjective, etc. So they can't be true or false the way a factual assertion is. And in this sense they cannot be derived from facts, because that would suggest they occupy the same status as  facts, which for these thinkers is false.

The knock against the fact value distinction as a matter of  internal consistency is this. The behaviourist asserts that the only statement that can be true or false is a statement of fact--one that is verifiable, observable, etc. All other statements are opinions, subjective, and neither right nor wrong.   But the statement "one cannot derive a judgment of value from an assertion of fact" is not a factual statement in the sense of one  observable in nature, verifiable and replicable in a laboratory or other scientific setting. 

So why treat it as anything other than the subjective feeling of the behaviourist, just like the behaviourist treats the statement "we should save a drowning person"?

Of course this argument is more of a gotcha than a full disproof. I suspect the disproof turns on the inaccuracy of the supposition that underlies the fact value distinction in the first place...