Justice seems complicated because you can look at intent or outcomes or opportunities or resources or?.

If only one student learns at twice the pace, should twice as much course material be purchased for just them?

What if there are two students moving at twice the pace, one has tutors and works three hours a day at home on their education, the other only does school work at school. Should they get the same school resources?

24 students in a classroom, 18 moving at the same pace and can receive the same instruction, three moving faster and three moving slower need additional instruction to support where they are at. If the teacher has time each week for 24 hours of instruction for the classroom, should 18 of those go to the middle level, 3 to fast, and 3 to slow? Or should it be 8 hours to each group.

It's a pretty muddled sort of moral/ethical mix that can leave me feeling a bit uncertain about just where the line of "fair" exists.