Answer: that parents would rather sell their children than be responsible for them.
Step-by-step explanation:
A False Premise refers to a situation where an argument is based on a wrong assumption. Normally this would mean that the argument would be wrong as well but sometimes this is not the case.
In this essay, the author, Jonathan Swift relied on the false premise that parents would rather sell their children than be responsible for them. In other words he was saying that parents would sell their children to the higher classes to to survive.