Final answer:
The logical error underlying the argument is 'begging the claim' because it assumes the conclusion to be true without evidence.
Step-by-step explanation:
The logical error that underlies the argument that Black people were inferior in the passage from the opinion of the court in Dred Scott v. Sandford is begging the claim. Begging the claim occurs when the conclusion of an argument is assumed to be true without providing evidence or support. In this case, the argument assumes that Black people were considered inferior based on their subordinate status at the time and does not provide any objective evidence to support this claim.
Learn more about Logical error in Dred Scott v. Sandford