Session 2 · Isaiah 5:20-21
Convention or Conscience?
Learning to tell a local custom from a standard that binds everyone
Book reading: Mere Christianity, Book One, Chapter 2 (Some Objections)
Anyone who talks about right and wrong for long will hear this objection: "Morality is just how you were raised." Book One, Chapter 2 is Lewis's answer to that, along with a couple of related objections. This session is about learning to sort things into two piles, conscience and convention, and about answering the objection kindly instead of winning an argument.
Lewis separates the Law of Nature from herd instinct, which is the pull to go along with the group. He also separates it from mere manners or social convention. His comparison to mathematics supports the claim that the moral law is closer to a universal truth than to a local custom. Customs differ from place to place and can change without anyone being wrong. A truth is something we discover, not something we vote on. The point is that when we say one society's morals are better than another's, we are measuring both against some standard that is not either of them.
Isaiah 5:20-21 shows the Bible working from the same assumption. "Woe to those who call evil good and good evil, who put darkness for light and light for darkness, who put bitter for sweet and sweet for bitter!" Think about what that warning requires. You cannot call good evil by mistake unless good and evil are real things that exist apart from what we call them. Isaiah assumes the labels can be wrong. If morality were only taste, the prophet would have nothing to complain about.
The next verse is a good check for our own motives: "Woe to those who are wise in their own eyes, and shrewd in their own sight!" Part of why "it's all just upbringing" is so appealing is that it is convenient. If a standard is only a habit, I can drop it whenever it costs me something. Honest reflection means asking whether my doubts about morality tend to show up right when I would like permission to do something.
So how do you respond kindly when a friend says morality is only upbringing? Here are a few moves that follow the spirit of the chapter. First, agree with what is true: upbringing does shape us, and customs vary. Second, ask a gentle question: have you ever thought a society, maybe even your own, was wrong about something? Where did that judgment come from? Third, don't rush. You are not trying to pin anyone down. You are helping them notice something they already live by.
Be humble about yourself too. Sorting convention from conscience is hard work. Some of what feels like a deep moral conviction may be habit, and some habits we shrug off may be convictions we are dodging. Ask God to help you tell which is which.
Key idea
Lewis distinguishes the moral law from herd instinct and mere social convention, and compares it to mathematics to show it is closer to universal truth than local custom, so "it's just upbringing" does not explain it.
Questions to consider
- Name one thing your family or culture does that you would call a custom, and one thing you would call a matter of right and wrong. How can you tell the difference?
- When do your own doubts about morality tend to show up? Is there a time when "it's just upbringing" would be convenient for you?
Journal prompt
Write about a belief you once held that you later changed your mind about, either a custom you outgrew or a conviction you came to hold more firmly. What did you measure it against when you changed your mind?
Practice
Dose: 15 minutes, once. 1) Draw two columns, "Convention" and "Conscience." 2) Put at least five things in each column, drawn from your own life, family, work or church. 3) Circle any item you were unsure about. 4) Write one gentle question you could ask a friend who says morality is only upbringing.