I didn't realize Mary had breezed into my office until she spoke. "Hi, Professor Theophilus. What's that you're playing?"

"Good morning. A Scarlatti sonata. Like it?"

"Sort of. But I thought you said you liked contemporary music." She threw herself into a chair.

"I meant the contemporaries of Johann Sebastian Bach. But I'll bet you're not here to talk about music!"

"Nope. This morning in my Con Law class, I was really ticked off by something a classmate said. What a fanatic. You're religious, aren't you?"

"I'm a Christian," I smiled. "I don't know whether you call that religious or not."

"Well, I'm not religious, but when I took your course I always thought you were fair, so I thought I'd ask what you thought about what she said."

"What did she say?"

"We were talking about whether legislators can restrict marriage to opposite-sex couples. She said she'd support a law like that because same-sex unions are 'against God's will.'"

"Why does that make you angry?" I asked. "Are you a same-sex union activist?"

"No, that's not my issue. I don't know what I think about same-sex unions. I just don't think legislators should be allowed to act from religious motives."

"So you don't think a law should be passed unless legislators can give a secular reason for it?"

"Yeah, like the good of society." Mary paused. "So do you agree or not?"

The computer shook out the last few notes of Scarlatti and made a little whuff as it closed the music player. "I think the good of society is what legislators should seek too," I said. "But isn't following God's will the highest good for society?"

"Maybe so, Prof, but just saying 'It's the will of God, so do it' doesn't convince anybody."

"So, your underlying principle is 'Legislators should have to give convincing reasons for their laws.'"

"That's it."

"Is saying 'It's for the good of society, so do it' more convincing than saying 'It's the will of God, so do it'?"

Mary got up and grabbed my guest mug, poured herself some coffee and sat down again. She frowned. "I see what you mean. Maybe not. But in that case it doesn't seem like anything could be a reason for a law. That doesn't seem right."

"The solution isn't to say less, Mary, but to say more. A religious believer like your classmate has to say more than just 'It's the will of God,' and a secularist like you has to say more than just 'It's for the good of society.' She has to say why the will of God is what she says, and you have to say why the good of society is what you say."

"All right. But it still seems to me there's a difference between saying 'It's for the good of society' and 'It's the will of God.' People can disagree about the will of God."

"Is the underlying rule then 'Legislators should only give reasons that everybody agrees with'?"

"Yes."

"But don't people also disagree about what's good for society?"

"Ye-es," admitted Mary. "Maybe I put that badly. I guess what I'm thinking is that people can change their minds about the will of God. Two generations ago a lot of people thought it was the will of God to segregate the races. Now most people don't."

"Two generations ago," I replied, "a lot of people also thought it was for the good of society to segregate the races. People can change their minds about the good of society just as easily as about the will of God."

She closed her eyes and shook her head. For a moment she was silent. "Okay," she said, "but look. A law is something that everyone is legally required to follow."

"Right."

"But in this country, no one is legally required to believe anything about God."

"Right."

"So it seems wrong to have, as your reason for passing a law, an idea that people are allowed to disbelieve."

I sipped my coffee. "Just to be sure we understand each other, give me an example."

"Sure. A legislator couldn't have the will of God as his reason for making abortion illegal, because citizens can't be required to believe that God is against abortion."

"Then would you also say a legislator couldn't have public health as his reason for making it illegal to sell spoiled meat, because citizens can't be required to believe that spoiled meat makes people sick?"

"That's not what I said!"

"No, but doesn't it follow from your principle? If legislators shouldn't be allowed to act upon ideas that people are allowed to disbelieve, what ideas could they act upon? Are there any ideas citizens are required to believe?"

"I guess not."

A hunch had been growing in my mind. "Mary, what is it that really bothers you about people mentioning God in political debate?"

"It just makes me furious."

"Yes, but why?"

"I think it's because ... I think it's because they claim to know what God wills."

"Is there such a difference between claiming to know something is against the will of God and claiming to know it's against the good of society?"

"Yes, because you can't ever know the will of God."

"Why not?"

"Because people disagree about it."

"Didn't we already admit that people also disagree about what's good for society?"

"Yes, but that's different. Suppose people disagree about whether raising the minimum wage would be good. The legislature can have experts testify."

"That's a good point," I conceded. "But don't experts disagree too? Some economists say raising the minimum wage will help unskilled laborers make more money. Others say it will throw unskilled laborers out of work."

"Then I'm stumped. I don't see how you could settle a disagreement like that."

"But the question has to be settled one way or the other. Either the minimum wage is raised, or it's not."

"I guess legislators just have to vote their feelings and let the majority rule." Mary made her face like a raisin. "And I know exactly what you're going to say next."

"Really?"

"Yes. You'll turn things around on me just the way you did before. You'll say that if legislators who disagree about the good of society should go with their feelings, then legislators who disagree about the will of God should also go with their feelings."

"Let me surprise you," I responded. "That's not at all what I was going to say."

"It's not?"

"No. I'm not interested in how legislators feel."

"Then what did you have in mind, Prof? You aren't going to leave me in suspense, are you?"

(I was going with a hunch, and leaving her in suspense was just what I wanted to do, so I took a long swig of my coffee before answering.) "Mary, I said earlier that your classmate has to say why the will of God is what she says, and you have to say why the good of society is what you say."

"Yes, I remember."

"But you don't really believe that's possible, do you?"

Mary looked startled. Then she slowly shook her head. "No. I guess I really don't."

"So when two different opinions are in opposition, you think 'going with our feelings' is really the only thing we can do."

"What else is left?"

"We could have each side give evidence and reasons for its opinion, and then see which one makes the most persuasive case."

"Maybe you could do that with the minimum wage. You can test what happened when the minimum wage was raised in the past. But I don't see how you test the will of God. And ... and ..."

"Yes?"

"To tell you the truth, I don't know how you could test what it means for something to be good for society, either. Maybe you were right. Maybe my classmate and I are in the same boat. Maybe we're both fanatics. Maybe everything depends on blind faith."

I cringed. "I didn't recommend blind faith."

"Is there another kind?"

"According to Christianity, faith doesn't mean you don't reason. It means you ground your reasoning on the trustworthiness of God."

Mary just stared. She said nothing. I asked, "Have I lost you?"

"Yes," she admitted. "You might be making sense, but if you are, I don't know what kind of sense it is. You might as well be talking astrophysics. Or you might have said that flying dogs are better than flying cats because they have a purer magic. I just don't know what you're talking about, Prof."

"Okay. If I've lost you, tell me how to find you again."

"I want you to explain how Christians 'reason.'"

"It's like this ..."

"Omigosh!" she cried, springing from her chair. "I'm late for my class! Can I come back and hear the answer tomorrow?"

"Sure, but ..."

"No time! See you at 10:30!" She was gone.

"Well," I thought, "I hope she remembers to bring back my mug."