The common good is that idea that whatever serves the most number of members in a community is deemed good. The common good is generally whatever rules or actions are needed to minimize the disharmony within the community.
The greater good is the idea that there’s a standard that we should collectively strive for to maximize the harmony within the community.
Depending on the demographics and characteristics of the community, whether either kind of “good” is actually good, is more a function of who’s left standing at the end.
Greater and common goods are about the collective needs of the individuals rather than individual individuals, where the community as a whole or as balancing interests of groups within the whole community – and not considering the interests of any individuals – but the decisions/actions of individuals contribute to either the common or greater good.
The common good, being about peaceful co-existence, is generally good under any system of objective or subjective measure. Paying taxes in exchange for services, following laws and social norms so as to as to not infringe on other people’s enjoyment or ability to live their lives as they see fit within the same rules. Your right to swing your arm ends before my nose begins type of rules and norms.
As long as the common good is mostly good, people are contented and engaged in society and committed to leave the status quo as it is.
The greater good is the higher order of good and it can be used for good purposes to address areas where the common good is not inclusive of groups of people – an example would be civil rights and social progress, where groups that were discriminated against, ie not included in the common good, have these historic wrongs righted or it can be used for bad purposes, which is to redefine what the common good is in terms of a narrower set of groups within the community – for example, the standby Nazi Germany redefining what a true German was and passing laws putting limitations on the rights of Jewish people, as if there was a limited amount of rights and freedoms or, in modern America, the issue of gays being denied marriage, as if allowing gays to marry diminished the marriages of straight people – anything that is to serve a deity or purist purpose is often deemed by those who benefit to be the greater good – and it comes down to great for them and sucky or worse for everyone else.
Individually, we contribute on a daily basis to the common good – when we take turns, when we don’t take more than we need and leave some for others, when we work cooperatively on common or group goals, when we treat others as we treat ourselves. We do not contribute to the common good when we put ourselves or put others above or ahead of the group, so it’s a fine balancing act of not shorting someone else or shorting ourselves.
Individually, we can also contribute to a greater good than living our normal lives allow – often these feel like calls to service or destiny. We are drawn to a greater good when we undertake an action that provides an example for others to follow because of the obvious benefits or improvement for the common good. This is as opposed to having others emulate the behaviours or actions by coercion, trickery or bribery to follow the set example, as exemplified by the behaviour or actions reduces the common good by eliminating or discriminating against segments of the community, with individuals of non-targeted groups joining in to avoid becoming outcast or because they benefit from casting people out.
Serving the common and greater goods, requires individuals to think beyond themselves; serving the common good is to think of other individual people as well as yourself and the greater good to think of other groups of people to whom the individual is not a member as well as your own group(s) – and creating a balance, a harmony, between and within.
To not serve either the common or greater good, is to serve your own or your groups’ narrow interest, usually at the expense of other people and groups. This is where the greatest dangers and threats to the whole of society lie, me at the expense of you.
To serve oneself alone, is to provide service to no one.