This weekend I went on a hike with three PhD students visiting the Theory group at MSR, Alice, Bob and Charlie. At the trailhead, we met hikers who recommended a trail that they were going to follow, different from the one we had planned. We didn't have a map but looked at theirs, tried to memorize it, and decided to follow their suggestion.
They had said that after a creek crossing, the trail would go up and get covered with snow. The creek would have been a fine stopping point for a moderate and very pretty hike, but we were not ready to turn back, so, in spite of the knowledge of the difficulties that lay ahead, we kept going.
To gather information, we asked every hiker we met what the trail would be like ahead of us (is there a model for that in TCS?). None of them had continued very far, so we could have taken the cue and turned back, but the uphill path in the forest would have been such a boring, disappointing place to stop, that of course we kept going.
Then snow appeared, and walking started to require attention. We could have turned back, but we were still able to follow the trail and see footsteps of the people who had gone before us, so we stubbornly kept going.
Then the trail disappeared. We kept going a little ways, but, worried about getting lost, were just about to turn back, when we heard hikers above us. Two men appeared, one with an ice axe, and informed us that, equipped with a GPS, they had made it up to the ridge, a thousand feet above; they seemed to find it no big deal, so we decided to follow their footsteps. Adventure! Exciting! So we kept going.
Walking up steep snowfields between the trees was hard going, particularly for those wearing sneakers. We considered turning back, but the view kept getting better and better. Finally, the voice of reason:
"-[Alice:] I think we should turn back".
"-[me:] How about if we just keep going for another 45 minutes?"
"-[Alice:] I think that's too long. How about 15 more minutes?"
"-[me:] Ok, sounds good."
Thus was common sense neatly silenced by me, and we kept going.
15 minutes later -- only Bob had a watch, he didn't say anything, and no one asked him about it. Oh, the pride! So we kept going.
Worries were expressed by Alice and Bob about how we would get back down, but I peremptorily declared that we should defer discussing such non-constructive thoughts until we had to face them, and so, with that problem temporarily solved in that expeditious manner, we could keep going.
No more objections were raised. To prevent other non-constructive thoughts, Charlie entertained us with the story of Lord Shackleton's expedition. Another 30 minutes -- suddenly the ridge was in sight, only a short distance away! In no way were we going to stop at that point. We enthusiastically kept going.
Nothing is more beautiful than a hard-earned view. No wine is sweeter than on a wide ledge with a steep ravine down in front and a vertical cliff down in the back. No food tastes better than up in the heavenly solitude of the high mountains. There is no wind, the late afternoon sun dries our sweat, and life is good.
Unfortunately, what goes up must come down. But how?
Off we went reluctantly. Down steep snowfields among the trees. Slow, careful, yet slightly hazardous. I worried that it might be a harrowing experience for those wearing sneakers. Then - the incident I feared: Bob slipped, fell, and started sliding on the snow. I heard the sound, turned back, tried and failed to grab his hand as he passed me, but didn't have the presence of mind to put myself squarely in his way, and he ominously continued towards the trees. Then - he managed to stop himself after just a few yards. Phew! It had all happened in an instant. But really, now that it was over, it was as though nothing had happened: all was well, no big deal. Still, that'll be an interesting memory from his time at Microsoft Research!
We resumed our slow descent, retracing our footsteps with much care. We managed not to fall again, and not to get lost in spite of a couple of brief false alarms. Back on the trail, back across the creek, back down the mountain, and finally back at the car, with at least 20 minutes of daylight to spare. Perfect!
What a great hike!
In hindsight, although the hike was fun and beautiful, going all the way to the ridge of the mountain was not a wise decision. But making such decisions online in real time is extremely difficult, if not impossible. Who can fight the irresistible urge to keep going? How can the longing to reach the goal not cloud one's judgement? At some point, part of me knew that we ought to turn back, but I could not bring myself to let that thought quite emerge into my consciousness. How do mountain guides know when to stop, I wonder? How does one learn that kind of wisdom?
And that is how MSR visitors and interns spent their weekends.