What does this passage mean in John Stuart Mill's essay On liberty?

Question

To make any one answerable for doing evil to others, is the rule; to make him answerable for not preventing evil is, comparatively speaking, the exception....
How does this have to do with liberty?
well yeah. but the rule is making him answer to something he has done which is an act of evil. but how is to make him answerable for not preventing evil and exception??

Answer 1

You could write a book on this question! Very briefly, though, Mill was concerned with both the letter and the "spirit"--the moral obligations--that come with liberty.

For Mill, "doing evil" in one way or another, translated into violating the legitimate freedoms of another person. And he (along with most of the earlier Enlightenment philosophes as well as the founding fathers of the United States) saw the defense of the liberty of all as the common obligation of all.

In short, if a person allowed another's liberty to be violated and took no action to counter that, he/she failed in the moral obligation to rise to the defense of liberty generally.

Put another way--could a person (say in antebellum USA) who had the power to free a slave but failed to do so, legitimately clame to be a real "champion of liberty?"

Mills' final point, of course, is that in such cases, people should be held accountable for the consequences of their choices, not merely their overt actions.

Answer 2

It has everything to do with liberty. To understand it, you have to know what liberty is about.

“Liberty is doing what you wish as long as you do not infringe the right of others” It is all about responsibility and accountability.

If you throw a broken glass on the road where people walk to their jobs, you have done something wrong, should be hole=d responsible and accountable for your dead.

If you walk on the same road and see a broken glass and do not remove it, it is wrong, you should be responsible and held accountable. Your non-removal of the broken glass; your silence, is considered a collaboration with the wrong-doer. You may not be as guilty as him, but you are still guilty to some degree. Won’t the society be a better society if we act in this way? RESPONSIBILITY and ACCOUNTABILITY.