This might be because a society is a group of individuals.
how do you know this? What reasons do you have for this assertion?
As for the first statement, yes, it is true that it is in the province of individuals to make moral (and non-moral) choices that often reverberate throughout that person’s life but also throughout the history of that person’s family, and I might add, even relations with others. For example, a woman who has an abortion, an immoral choice, carries with her this deed throughout her life, and because the newly created person was deprived of life, his/her destiny was cut short so that God’ will could not be fulfilled in that new person He created for a particular purpose. (However, if there is repentance, God will bring good out of evil.)
Even more so, choices made by an individual who is a ruler/political leader of sorts, will afffect the lives of citizens near and far and even into the annals of history. Although these choices are made by individuals, we could consider that each individual person is a “product of society” and is influenced by many things. It is easy to see that youth are first influenced by parents, then peers before entering adulthood where they are then influenced by political parties, religious faith, organizations they join. Nonetheless, we are, each and everyone of us, responsible for our choices and actions.
Also, societies are influenced by the philosophies of the age. Consider that early societies were held together by their gods, such as the early Greeks until neighboring gods brought havoc and relativism to their society.
“Man needs wisdom, but what he needs and what he buys are two different things. Wisdom may cry a the gates, but man is too busy at the mall to hear. He likes to hear Protagoras say that man is the measure of all things, and concludes that the good or the evil or the existence or nonexistence of a thing depends upon how he chooses to consider it.” (Anthony Esolen: The Politically Incorrect Guide to Western Civiliization
As for your question how do I know this (that there is a “conscience” or moral understanding about right and wrong? Although a conscience must be developed, there is still an understanding “in our hearts” (souls?) that, for example, murder, theft, coveting, pride, gluttony, lust (all the cardinal sin and in any way we are unlike God–imperfections) are evils of various degrees.
Consider that all life forms have a life principle that animates that form. All animals have this. Some contends that even plants do. Obviously, the life principle in human beings is much higher than that of the animals. The Catechism of the Catholic Church points out that Scripture uses the term “soul” to denote a human life and, also, to describe the innermost aspect of man. It is in this way that we are made in God’s image; it is the spiritual principle. (No. 363).
Catholic Answers relates that “the soul is the seat of our intellect and our will, including such aspects as consciousness, reason, memory, imagination, emotion and conscience.” Our soul and body are so intimately joined in this life that whatever affects one, has influence on the other. Therefore, “every time, in the body, we freely perform an immoral action, it is only because our soul–the animating principle–has chosen that action. This is why conscious bodily actions have eternal consequences. This is why sacred Scripture tells us that 'we must all appear before the judgment seat of Christ, so that each one may receive recompense, according to what he did in the body” (2 Cor. 5:10)."
“In those respects in which the soul is unlike God, it is also unlike itself.” (St. Bernard)