system
Given the following post, respond as if you're commenting on Reddit:
human
You can't form an "ought" from an "is"?

This phrase comes up a lot in internet debates and it always seems to end the debate, which seems wrong to me. What can you say in reply? What *can* you form an "ought" from? The trouble is that most statements you can make seem like "is" statements, even those about values, which would seem to be where the answer should come from. Is it just a debating trick?

I understand the phrase arises from Hume's philosophy but I can't find anything about it on his Wikipedia page.
gpt
It can be a little confusing to think about in the terms in which it's couched, since even obviously normative propositions like "it's wrong to cause unnecessary pain to others" are framed as "is" statements. But all Hume is saying here is that you can't get from purely descriptive facts to normative ones. So like: 

P1) Infidelity causes harm 

C) Therefore, infidelity is wrong 

is an example of an argument that would fall afoul of Hume's guillotine, and, as it happens, it's invalid. But something like: 

P1) Infidelity causes harm

P2) Causing harm is wrong 

C) therefore, infidelity is wrong

would not. It's really more about descriptive versus normative/evaluative than the literal words ought versus is. (Plus, any normative "is" statement could be rephrased in "ought" terms to avoid the semantic confusion).  Did this help at all?