Parallel Argument vs Original Argument

This procedure is admittedly imprecise. There will sometimes be disputes about whether the premises of the parallel argument really are true, or clearly true, and whether the conclusion of the parallel argument really is false, or clearly false. Moreover, we have given no general explanation of the notion that two arguments have the same basic form. Some forms of argument were discussed in previous chapters, but they are only part of the story. We have not discussed and cannot discuss all possible forms of argument. Yet it remains a fact that people can often see that two arguments have the same essential form and, through seeing this, decide that an argument presented to them is invalid. This ability is the basis of sound logical judgment. It is also the basis of wit. It is at best mildly funny to say that if God had wanted us to fly, He would have given us wings. You have to be fairly clever to reply at once, “If God had wanted us to stay on the ground, He would have given us roots.”

In each of the following examples, does the parallel argument succeed in refuting the original argument? Why or why not? Consider the three possible responses listed above. If the original argument is refuted, is there some simple way to fix it so that it cannot be refuted by this parallel reasoning? If so, how? (You might try to add a premise whose analogue would be false in the parallel argument.)