What argument does the author counter in this excerpt from Thomas Paine's Common Sense?

I have heard it asserted by some, that as America has flourished under her former connection with Great Britain, the same connection is necessary towards her future happiness, and will always have the same effect. Nothing can be more fallacious than this kind of argument. We may as well assert that because a child has thrived upon milk, that it is never to have meat, or that the first twenty years of our lives is to become a precedent for the next twenty.