You can overpower a human being. You can tie him up, lock him up, injure him. Others can bring his body and his outer life under their power.

But no one can coerce the free will itself.

How is that possible?

The will can always withdraw from everything external. We already know this from the start of the book. It can say: “Then just take it.” A blackmailer’s power lasts only while I cling to what he threatens.

Think of people who chose to lose everything rather than betray their friends. Others could take everything from them. No one could break their will.

A hard sentence:

From this follows a hard sentence: You can coerce only a person who wills to let you coerce him. Whoever gives in does so because he will not let go of something external. His will holds fast to this thing.

Summary: You can overpower the body, but not the free will. You can coerce only someone who holds fast to the external thing by which you grab him.