At some point in any discussion of societal justice, the only possible doctrinal defense seems to be “That is the way we do things here.” Different communities that each recognize the dignity and equality of all citizens will, for example, nevertheless settle on somewhat different provisions for the elderly.
Conclusion (So)
General principles of justice are never sufficient to determine the details of social policies fixed within a particular state.
Evidence (for example)
Different communities that recognize the dignity and equality of all citizens settle on somewhat different provisions for the elderly.
At some point in a discussion of societal justice, the defense is "That is the way we do things here."
Evaluate
The argument suggests that even if societies adhere to similar overarching principles of justice, they will still arrive at different detailed social policies. This suggests that broad principles are not enough to prescribe specific societal policies.
If we were being skeptical, we might say,
So an answer can help convince us that
Goal
Let's find an answer that shows societies with similar, general principles of justice implementing different specific policies, reinforcing the idea that these overarching principles don't alone dictate specific policy details.