Is–Ought Fallacy
Logical fallacyMoving from a description of how things are to a claim about how they ought to be, without supplying the moral premise that would connect the two. Identified by David Hume.
An everyday example
“Every society so far has had great inequality, so inequality is as it should be.”
The same move in this debate
“Animals eat other animals, so humans ought to eat animals.”
Where this appears
A fact about human physiology is offered as a conclusion about what we should eat, with no premise supplied to connect the capacity to the entitlement.
Even granting the anatomy in full, nothing follows about what we ought to eat without a premise connecting physical capacity to moral permission.
An account of how our brains developed is converted into a conclusion about how we should eat now, with no premise licensing the move.
Moves from the fact that we do breed animals for food to the claim that this is their purpose, with no premise connecting the practice to the entitlement.
Moves from what predators do to what humans ought to do, supplying no premise that would license the step from description to obligation.
Moves from a claim about where cattle belong to a conclusion about what we should do, without the premise that would connect the description to the obligation.
Moves from a description of what humans have historically done to a claim about what we are now entitled to do, with nothing supplied to bridge the two.