Independent reader · Session 1 of 33
A Shared Core and the Law of Human Nature
Romans 2:12-16
Start with what Christians hold in common, and with the fairness you expect from everyone else
Book reading
Mere Christianity, Preface; Book One, Chapter 1 (The Law of Human Nature)
Before you get into the argument, take a minute with the title. In the Preface, Lewis explains what he means by "mere Christianity." He means the core beliefs Christians share. He presents them while deliberately steering around contested denominational questions. So you are not about to read a defense of one church's way of doing things. You are reading a case for the shared center.
That gives you a job before you start: decide for yourself what you think the shared core is, and which disputed questions you are setting aside while you read. Churches disagree about plenty, such as how baptism works, how a church should be governed, and what worship should sound like. Setting those aside is not saying they don't matter. It just keeps them from blocking the road while you look at something bigger.
Now to Book One, Chapter 1. Lewis begins with something nobody needs a seminary degree to recognize: ordinary quarreling. When people argue about fairness, they appeal to a standard they assume the other person also knows. Think about "You promised," or "That's not fair," or "How would you like it if someone did that to you?" Nobody says those lines expecting a blank stare. We assume the other person will get it. Lewis treats this Law of Human Nature as a solid, widely shared fact. He adds an uncomfortable second point: everyone believes in right and wrong, and none of us keeps the standard consistently.
Paul sketches the same ground in Romans 2. He says Gentiles, who did not have the law given to Israel, "by nature do what the law requires." They are "a law to themselves." Then he goes a step further: "They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them." Notice those last two verbs. Inside us there is something like a courtroom, with a voice that accuses and a voice that makes excuses. Most of us are fluent in the second voice.
Paul also closes the escape hatch of simply knowing the right thing. "It is not the hearers of the law who are righteous before God, but the doers of the law." Knowing the standard and keeping it are different things. Lewis starts his whole book at that point. He does not begin with a creed or a church. He begins with the standard we all lean on when we are the ones who have been wronged.
That can feel like bad news, but it is a starting place. A person who never senses a gap between how things are and how they ought to be has no reason to look for help. Over the next several sessions you will watch Lewis follow that gap to see where it leads. For now, just notice it in yourself, honestly and without panic.
Key idea
Lewis frames the book as a case for the shared core of Christianity, and he starts from something everyone does: appeal to a fairness standard we expect others to know, and then fail to keep it ourselves.
Questions to consider
- What would you put on your list of beliefs that Christians across many churches share? Which disputed questions are you willing to set aside while reading?
- Think of a recent time you appealed to fairness ("that's not fair," "you said you would"). Did you hold yourself to the same standard in a similar situation?
Journal prompt
Write down one recent argument or frustration where you expected someone to just know what was fair. Then write about a time you did the very thing you were upset about. What did your inner voice say each time, the accusing one or the excusing one?
Practice
Dose: about 10 minutes now, plus a day of noticing. 1) Make two short lists: "Shared core" (3-5 beliefs you think all Christians hold) and "Setting aside for now" (2-3 disputed questions). 2) Over the next day, jot down three times you or someone near you said something like "that's not fair." 3) Next to each one, write the standard being appealed to and one time you fell short of that same standard.