He did not know what he could use it for, so he tried lots of different things. It wasn't very good at holding water, and was pretty rubbish at transporting rocks. It didn't keep meat fresh, and while it did make pleasing scrunchy noises, or could be blown up and hit with a hand to go BANG, it wasn't the same afterwards.
The man scratched his head for a bit, and then realised the paper bag was head-sized. He thought that putting it on a head would keep it dry and scrunch-free while he had the time to think what the bag could be used for.
He tried putting it on his own head, but while it did give him thinking time he couldn't see where he was going. So he put it on his wife's head, and promised to be her guide.
When they went out shopping the man noticed people did not flirt with his wife. The man's wife had thick and beautiful hair which people often commented on, and it always made the man jealous. Now no-one could see her hair and he was not jealous.
Also his wife was quieter. She did not chatter to the stallholders or flirt with other men, and relied upon her husband to lead her to the right shops. She could only talk to him, because with a paper bag on her head no-one else would talk to her.
All this pleased the man, and so it became a regular thing. Every day he would lead his wife to the shops with a paper bag on her head, and at home he was the only man to know how beautiful she was.
With time, people in the market became used to the man and his wife with a bag on her head. They forgot what her name was, and only spoke to him. When the couple had daughters he made them paper bags of their own, too.
After a while the man's friends asked him to make paper bags for their wives as well. One man, whose wife was very beautiful, had been attacked by a stranger and he thought if no-one could see her beauty she would be safe. Another man, whose wife was very argumentative, thought it would stop her haranguing him in the street. A third asked for bags for his daughters because they were rebellious and he wanted them to be meek.
The man made all the bags he was asked for, and was proud of his invention. One of the rebellious daughters decorated hers with shiny things, and then all her friends from school asked for paper bags too because they all wanted to be the same, but just a tiny bit different.
"It's called fashion," the man's wife told him. He shrugged, and made accessorised paper bags because he could charge twice as much that way.
In a few years every woman in the town had a choice of paper bags for different occasions, decorated ones, plain ones, patterned ones. It became known as The Town Of Women Who Wear Paper Bags, and tourists sometimes bought them to take away as a novelty and show people what the funny foreigners do.
The man who invented the paper bag was rich and happy. His wife almost never spoke to people outside their house, and their daughters were growing up just the same.
But he no longer took her shopping every day. He didn't have the time. His wife would often ask to go out, but because she always wore a paper bag on her head and needed him to guide her she usually had to stay in.
The man knew his wife was unhappy, but he was not prepared to let her go out without the bag on her head. It had been such a long time now it would cause uproar. So he cut some eye holes in the bag, and she was able to go to the shops but still no-one knew her name, or looked at her hair, or spoke much to her.
Because he no longer had to guide her, the man could carry on with his own things. He became selfish, and counted his money, and became terse with his family. He did not ask his wife her opinion.
Shortly afterwards a priest arrived in the town, bringing word of a faith which was very similar to all the others that were around at the time.
It was born of rocks and sand, so its roots were hard and dry. It told people to be good in this life in order to be three steps ahead in the next one, told them to love one another while killing those that didn't love them, and it was written by men who didn't really like women to do their own thing.
The priest saw that all the women had paper bags on their heads, and he liked the idea. He thought that women needed to know their place, and this was with men as their guide. A man had invented the paper bag and women had accepted it, so he thought it would persuade the town to adopt the religion if he showed how much it suited people with paper bags on their heads.
And so, while he did not write it into the holy book, the priest often preached that paper bags were the way towards familial harmony and marital happiness. He warmed to his theme, and said that without paper bags there would be social discord, rape, murders, all sorts.
The people of the town - who didn't speak much to towns elsewhere, and weren't to know that crimes were pretty much the same all over regardless of what you wore on your head - liked the priest because he said the things it suited them to believe.
But the wife of the man who invented the paper bag was getting bored. Her husband was rich, they had a religion which answered all their questions, and everyone copied what they did. They copied the paper bags, the eye slits in the paper bags, and when one of her daughters wore her paper bag in a more rakish fashion some of them copied that too.
The wife should have been happy, but she was discontent. Her husband no longer guided her, people in the market no longer spoke to her, and no-one ever gave her compliments on her beautiful hair any more either. Her husband had long since stopped bothering, and no-one else could see it.
No-one knew her name.
She decided she would like to get a job. That way she would not have to be bored at home all day with a husband who was not as loving as he used to be, she could talk to people, and she could earn some money of her own with which to buy her husband or daughters gifts. Perhaps she could even invent something as good as a paper bag herself.
So the wife went to the market and asked people for work. Most of the stall holders were men, and most of them could not hear her properly because of the paper bag. Eventually, one told her that he could not employ someone with a paper bag on her head, because customers would not like it.
"Human interaction is based on more than just hearing you speak," he said. "It is also about body language and eye contact, about how you hold your head and the expression on your face. We already can't hear you clearly, but it's very difficult to see any of this other stuff at all through a paper bag. People don't like it - not because they hate you, or paper bags, but because they want to interact with you. I think I could only employ you if you took off the paper bag."
"But the priest says we should wear paper bags all the time," said the wife. "And my husband wouldn't like it."
"Then we are at an impasse," said the stallholder. "Besides, have you been to school?"
The wife admitted she had not, and the stallholder said she would need to know some maths. So she went to the town's school and asked for lessons.
There, a teacher told her she could only have lessons if she took the bag off. "How can I teach you otherwise?" he asked. "I need to see the comprehension in your face, to know that you have learned. It is an interaction. Besides, the priest says we shouldn't educate women."
So the woman went to the priest. "Please," she said. "I am in a quandary. I would like to talk to people, and work, and be educated. I think I will be happier that way than I am now, waiting for my husband to allow me to do things. But I cannot with a paper bag on my head.
"Yet the bag itself is not harmful to me; I do not mind it, most of the time; and you tell us if we take them off we will suffer. But I suffer also with it on because there are things beyond my reach. What shall I do?"
And the priest, who was a wily man, said: "Let's have a vote."
So he called a meeting in the town square, and invited all the people telling them they would each have a chance to speak on this great issue.
There were men who said women should always wear the paper bag, it keeps them safe. There were girls who said I want to be grown-up, like my mother, and it is my choice to wear the paper bag so I can be like her. There were boys who said they would not marry a girl who did not wear a paper bag because it showed a lack of morals. And there were women who said we are happy like this.
There were those who said it was part of their faith, even though it was written nowhere in the holy book. There were those who said women covered their heads and hair all over the world in many faiths, and it was just a thing. There was one idiot at the back who piped up there was no-one on Star Trek in a paper bag, and she got pelted with rocks.
People from other towns heard about the debate and turned up to throw in their twopenn'orth. There were feminists who said a woman may choose to wear paper bags if she wants, and Liberal Democrats who said it wasn't for them to say while saying it was wrong and slapping themselves in the face for being illiberal. There were racists who said people only wore paper bags because they were planning to blow everyone up, and members of the commentariat not one of whom could make up their minds in case they were seen as illiberal or racist or feminist or misogynist.
And the wife heard all this, and saw the priest had called a vote he knew no-one would win so that nothing would ever change and no-one could answer her question.
She stood up, and cleared her throat.
She said: "I can understand all that everyone here has said. But I think the only people who can decide whether or not to wear paper bags on their heads are the people whose heads the paper bags are on.
"I also think the best way to make that decision is to be educated, not just in how the paper bag came to be invented and why we started wearing it, but also in science and maths and languages and what other people think about things.
"It is quite clear that it's harder to communicate with people wearing a paper bag, so perhaps for lessons we could cut a hole out for the face, or take them off entirely. School teachers can be a rum bunch but I've never yet heard of one turned bad by a woman's hair.
"When I have had my lessons, when I have got a job, and played a part in the society and economy of the place in which I live, I will be able to make my own decision about whether or not to wear a paper bag on my head. Perhaps I will like the freedom from sexualisation, and perhaps I will prefer to be bagless so everyone can see me for what I am. I do not know, but I would like to be able to choose.
"The bag does not make me love my husband more or less. It does not make me a fool, nor a genius. It is just a paper bag I wear on my head, and which unfortunately means that in the place where I live I am more likely to stay indoors, not leave my town, never go to a place or a time where things might be different. Different is not always bad. Paper bags were different, once."
The wife turned to the priest, and said: "You want women to wear paper bags because you are afraid that if we do not we will not like your religion so much. Yet I have heard there are men and women all over the world who do not wear paper bags and follow your faith. If we must trust you, why will you not trust us?"
And she turned to her husband, and said: "You put the paper bag on my head because you did not want it on yours. You did not want men to look at me, but you still look at women. Yet when we married we promised to be companions on equal terms. Will you let me be your guide?"
And she produced a blindfold, and tied it around his eyes so that he could not see, and relied on her to lead him. "I cannot see where I am going," he cried. His wife replied: "You never could."
To her daughters, the woman said: "Do not wear paper bags because I do. Learn about them, live life with and without them, and choose the one that suits you best. All I want is for my daughters to be happy, and to have better lives than me - if you wear a paper bag because someone has told you to, we have all failed."
Lastly the woman turned to the populace and told them: "The wearing of paper bags is a silly thing, in the great scheme of life. It is silly to think a woman who does not is immoral, or a hazard to men, or inviting sexual assault. But it is also very silly to think that a woman who does is a danger to society or about to blow herself up.
"If your society is strong enough, it can withstand a paper bag. And if it cannot, well, then it's not much of a society, is it? And by the way, my name is Eve."
With that the woman turned, and leading her husband, went off into the future.
And they all lived.