The quote "Our guilt has its uses. It justifies much in the lives of others." refers to the idea that guilt, although often seen as a negative emotion, can serve a purpose. It suggests that our feelings of guilt can be used by others to justify their actions, behaviors, or attitudes towards us. It’s a commentary on the human tendency to use others’ guilt as a means to absolve ourselves of responsibility, to validate our own actions, or even to manipulate situations to our advantage.

In the first part, "Our guilt has its uses," the speaker is acknowledging that guilt can be functional. It serves as a moral compass, pushing us to correct our wrongs and improve ourselves. It’s a driving force for change and growth.

The second part, "It justifies much in the lives of others," is a bit more complex. It suggests that our guilt can be exploited by others. For instance, if someone knows we feel guilty about something, they could use that guilt to manipulate us or to justify their own actions or attitudes.

Applying this quote to today’s world, we can see how guilt is often used in various societal and interpersonal contexts. In politics, for instance, leaders might use the collective guilt of a nation to justify certain policies or actions. In relationships, one person’s guilt might be used by the other to justify control or emotional manipulation.

In terms of personal development, understanding this quote can help us be more aware of our emotions and how they might be used by others. It can teach us to manage our guilt in healthier ways, using it as a tool for growth rather than allowing it to be a source of manipulation. It also encourages us to examine our own behaviors and attitudes towards others, ensuring that we’re not exploiting someone else’s guilt for our own ends.

In essence, this quote serves as a reminder of the complex interplay between personal emotions and interpersonal relationships, and the importance of emotional awareness and integrity in our interactions with others.