In the Buddha's days - just about the same time he was establishing Buddhism - there was another religion established, the Jain Religion. The Jain religion was more extreme than Buddhism in which they actually wear a veil on their mouth so that they will never accidentally breathe in another creature. When they walk the streets they sweep the path in front of themselves. This appears to be extreme to the point of paranoia. The Buddha taught the middle way and not to go to extremes.
Why do we do walking meditation? What's the purpose? The purpose is not just to walk back and forth, and kill insects, etc. The purpose is to develop your mind. This is a good intention. That's the actual purpose. You walk back and forth to develop your mind.
Why walking meditation, why can't we just not do it because we might kill insects, and stand and sit all the time and never move at all? Because in normal daily life you move. In normal life you are moving all the time. Walking meditation is the link between formal mediation and your normal life, you put the two together. You learn to formally meditate when you walk, which means while you're moving. That means you can meditate while grabbing a door, sitting down on a toilet, eating your food, brushing your teeth, everything else. If you never practice meditation in a movement activity, how are you going to be able to do it in your normal life when you move? You've got to practice it. So, the walking meditation is the time you are practicing being aware of movement. It's an important part of this practice. Some teachers don't teach it at all, we definitely do. When you think of the purpose, then you don't stand still, afraid of possibly killing insects.
However, when we have Compassion/Lovingkindness as our intention at the time, we are more careful. We are not going to just walk blindly and step all over everything. The eyes are going to be down, two meters or so, we are going to look out. If we see that there are too many insects in this walking track, we go to another one. When I'm walking and I see the ants making a trail across the track, I will get sticks and put them down on each side of the trail so that I can remember they're there, and try to step over them. Especially if my thoughts get lost, I still see those sticks and I will go over the sticks. You can make adjustments in that way to make certain as much as possible you don't kill any other creature. But it's important to think of the intention for the walking. Then it doesn't stop you from actually walking.
In Thailand, at some of the monasteries Rosemary and I have been, they often don't have electricity. Which means at night if you are going to do walking meditation you put out candles. Ok, candles. Have any of you put candles outdoors? What's one of the first things that happens within ten or fifteen minutes? The flies, the moths, etc. come flying right into the flame and they die. Personally, when I am at those meditation centers that don't have electricity I will never walk outside at night. I won't light the candles. If I have a tiny, tiny hut to sleep in which has about three meters distance, that will be my walking track at night. So, we can try to limit the extra deaths that could occur when we do walking meditation.
And you can't totally stop everything, otherwise you are just going to sit still for the rest of your life and you are going to die there, too. Because you won't be able to eat. As you've heard me say, eating, the growing of virtually every food on the planet, causes deaths of other creatures. Even the Jain religion doesn't go to this extreme, they don't starve themselves to death not to harm other creatures. You write on paper. Where did paper come from? 95% or so of the earth's paper comes from trees. The rest comes from paper that used to be trees. What happens when you cut down a tree? They fall and they go smash, boom. They often shake. How many creatures live in every tree? And how many die every time a tree comes down? Just to have paper we are in the process of killing. So we actually can't stop being part of the process of killing, but we can limit it, we can slow it down.
When we teach to do the Compassion/Lovingkindness before the walking, we want you to have in your thoughts that, yes, if I walk I may accidentally kill some creatures. And we want you to take those thoughts further into your normal life, too, that's the purpose of it, to take it even further. That as you are doing anything in your normal life other beings may die. Can you then dedicate yourself to lessening that as much as possible and growing as much as you can so that you can make your life useful and inspire other people?