John was a lumberjack. Every day he would go to the forest, chop down trees, and haul them back to town to sell to anyone who needed lumber. Fortunately for John, everyone needed lumber, all the time, as the town had many flourishing businesses and the population was growing.

Because demand for lumber was always high, whenever John wanted to make a bit of extra money, he could push himself to work extra hard and cut down a few more trees to sell. While it was demanding work, he always felt incredibly gratified after such days. Not only was he rewarded for his effort; he knew he was also providing extra value to the people of the town, who could always put the lumber to good use.

One day, a traveling salesman came into town and showed John an incredible tool he had never seen before. The salesman called it a "chainsaw" and showed John that with very little effort, this tool could cut through logs in a fraction of the time it would take him with an axe. The chainsaw was awe-inspiring to John, who could plainly see that it would be more than worth the expensive price tag after only a short time given the number of trees he would be able to cut down.

Sure enough, the next day, John brought more than twice his usual daily haul of lumber into town. The people were astounded and overjoyed, and everyone congratulated John on his wise investment. John made more money than he had ever earned in a single day before, and went to bed that night knowing that his life had changed.

Weeks went by, and John continued to earn far more money than he ever had before. The people of the town built more and more with the lumber John supplied. Everyone was happy, but John started to wonder if he might be able to do even more. It was as if a switch had been flipped in his mind: seeing just how much of a difference the chainsaw had made, he soon began dreaming of other ways to achieve similarly transformative gains in the amount of lumber he could provide to the town.

After many late nights spent tinkering with the chainsaw he had bought, John finally came to understand the inner workings of the tool well enough to recreate it. But instead of creating a chainsaw with the same dimensions, John produced one that was 100 feet long. The night his work was finally completed, John went to bed as excited as a child on the night of Christmas Eve.

The next day John brought his 100-foot chainsaw into the forest eager to try it out for the first time. To his delight, in a matter of minutes, he was able to cut down not a single tree but dozens of trees nearly simultaneously. In a single sweeping gesture, John's new chainsaw ripped through trunk after trunk, scattering wooden splinters across the forest floor in a breathtaking display. Trees fell one after another causing the ground to shake and filling the air with a thunderous chorus of crashing branches and limbs.

When John finally returned to town with his haul of lumber at the end of the day, the townspeople were speechless. They had never seen so much lumber produced in a single day. It changed everyone's sense of what was possible. The business owners in the town updated their ambitions accordingly, planning for larger and larger construction projects to utilize the vastly increased supply of lumber now available to them.

Over a year passed, and John had become a very rich man. While he was incredibly proud of his work, once in a while he experienced a tinge of nostalgia. He remembered the thrill he experienced building his 100-foot chainsaw and using it for the first time.

Eventually John started having trouble sleeping. An obvious truth was lying just under the surface of his consciousness, waiting for him to acknowledge it. One night it forced itself into his awareness, hitting him rattling force: Why stop at 100 feet? Imagine how many trees you could cut in a day with a chainsaw a mile long.

It was an engineering challenge like nothing John or anyone had ever attempted. His neighbors helped him with the materials, and eventually with storage as he worked on creating a tool of such magnificent scale. Before long John was working on a chainsaw that stretched all the way through town. Transporting it to the forest was an ordeal, but he knew it would be worth it.

When the chainsaw first roared to life, John felt a rush of adrenaline like nothing he'd ever experienced. As he slowly lifted the chainsaw and began moving its blade through the forest, the sound of hundreds, thousands of trees being severed at the base and falling to the earth was almost deafening. The experience was overwhelming for John. For the first time, on that day, he cut down so many trees that he couldn't even see how many were falling. He wasn't sure how much lumber he could transport back to the town. He did his best to load up everything he found, but there seemed to be no end to it. When he finally returned home at the end of the day, he did so knowing that he was leaving some fallen trees behind.

The next day, John carried the chainsaw to a different part of the forest. Again, the metallic scream of the chainsaw ripping through an endless swath of foliage echoed far and wide. John returned to town again with every piece of lumber he could carry, knowing he wasn't able to collect it all.

After this carried on several more days, a stranger visited the town asking for the one who was tearing down parts of the forest with a howling blade. The people of the town sent the visitor to John, who greeted him and asked him why he had come. The man explained that he had been living in a secluded cabin in the woods, until John's fearsome weapon had appeared and destroyed his home.

John was deeply moved by the visitor's story. For a few days, he took time to reflect on his actions. He knew that the lumber he provided helped the people of the town. Was the value he provided to them enough to make up for the damage he had done to the visitor's house? He thought long and hard about it.

Eventually, the townspeople started visiting John and asking him to resume his work harvesting lumber from the forest. They needed it, they explained to him. Without it, the town could not continue to thrive.

John decided to hire some helpers. They would join him in the forest and spread out to survey areas for dwellings or anything of value that he shouldn't damage. Of course he couldn't hire enough people to be absolutely sure he wouldn't do any harm; but having the help soothed his conscience, and the business owners in the town were thrilled for him to get back to work providing their lumber.

This worked well for some time. Unfortunately every now and then John would still discover that he had accidentally destroyed someone's home or other property. But this was rare enough, and the value he provided to his town was so great, that he was able to continue sleeping at night knowing he was doing far more good than harm.

Years have passed. The needs of the town (now a city) have scaled tremendously, and with them so has John's output. Today he uses a chainsaw that is 100 miles long. He employs a considerable workforce responsible for surveying entire forests to help him decide where to clear trees for lumber production.

These days, it simply isn't possible for John to know how much damage he is doing. A 100-mile chainsaw can clear over 30,000 square miles of forest at a time. Even with the help of his team, a single person simply cannot assess the impact to such a large area. At this point John has become accustomed to learning that there are times he has accidentally destroyed entire villages. He still believes that the good he is doing by producing such vast amounts of lumber outweighs the unfortunate cost.

And if it weren't, how would he know? Why should he stop? What John knows is that the lumber he supplies is still being used by the city. And the visitors from the forest stopped making their pleas long ago.