Immanuel Kant believed that good will comes from inside and is not forced on a human being by anything external. He also considered the "good" to be fairly universal. By "without limitation," Kant means that, out of all good things in the world, only good will exemplifies "goodness" as an absolute. It's the only thing that cannot fail in being good.

A lot of things can be described as good, but all of them can falter, so to speak. For example, Kant is very careful not to say "good act" instead of "good will." If a person truly wants to do and be good, without any need for acknowledgement or rewards—that is Kant's good will. It's selfless, motivated only by the inherent moral drive.

Everything else that follows is already subject to failure and dispute. Take, for example, a person who wants to do good. Other than their desire to act morally, everything could go wrong. They could choose the wrong way to go about it, they could help out by accidentally causing someone else harm, or they could even do a good thing and then be struck by unforeseeable bad consequences. Acts have limitations and so do people. There are so many variables in the real world that almost nothing is untouched by subjectivity; what's good for one may not be so for another.

In Kant's mind, in that whole equation, only the good will remains pure and untouchable. Even if it's misguided, or if it fails in execution, the drive to be and do good is the one thing that can't be corrupted—that can never be bad.

Kant believes that the only thing that is absolutely, unconditionally good is the good will. It is the good will, the rational will, that according to Kant is the source of all true moral actions. We don't act morally because we're forced to; we don't act morally because we want to; we do it because we choose to follow the rational moral will that exists inside each and every one of us.

Kant argues that we are all morally autonomous. This means that we essentially choose to give the moral law to ourselves and act upon it. This doesn't mean that we can do whatever we want; although we choose to act morally, the actual content of the moral law is dictated by the demands of reason. Moreover, it must be possible to universalize moral acts, so that when we act in a certain way, we try to imagine that everyone else in a similar situation would act accordingly. This universal quality of the moral will, as well as its rationality, is what makes it an absolute good, at all times and in all places.

Kant, the German Philosopher from the 18th century, believed that good did not so much arise out of our experiences, or from agents acting outside the physical self, but that humans through reason had developed morals - a sense of right and wrong - and that a "good will" was intrinsic.  That is to say, humans had a good will, or acted from that good will, because they believed in the moral goodness of an act without any outside motivation to do so.  To put it another way, Kant was saying that true goodness comes from the heart, not because of some reward or fear, so that goodness of the human heart is unlimited because its source is within us.  It's a very interesting and hopeful idea.