Riding fast on the MTB is an entirely different experience than riding fast on the road since the trail is rough, has many twists and turns and many rapid ups and downs. Also many of the obstacles, like trees or rocks are inches or just a couple of feet away on the trail, while the road is built for cars and trees and other obstruction are several feet away so you don't even have to be aware of them. Riding 20 miles per hour on the MTB feels like warp speed, on the road that is just cruising along speed.
One of the "weird" elements of riding the MTB fast is "you" have to look where "you" are going to engage whatever neural/muscular system actually pilots the mountain bike. That is "you", your verbal and symbolic mode of consciousness really isn't driving. In fact, if "you" start thinking words and concepts, they are distractions that disrupt the actual pilot.
That kind of split in consciousness can happen in a car as well. Many times when people commute to an office by car, the "driver" of the car allows the verbal/symbolic mode of consciousness to flit away into a fantasy realm so the miles pass almost unnoticed. The I "ends up" at work as if the drive was passed in slumber. The opposite of that might happen when some emergency situation happens, like if a tree limb suddenly fell on the road, or in winter, the car loses control on a patch of ice.
The question is, "who is the pilot"? Is the pilot of the MTB the same thing as "me"?
No. The MTB scenario gives me a very clear answer on this question. One of the "tasks" for the verbal/symbolic consciousness during the MTB ride is to remember to keep looking down the trail because the eyes "steer" the bike. The verbal mode of consciousness routinely fucks this up. One well known example is "object fixation", while sweeping the eyes through a turn, the verbal consciousness, that is the "I", will go into worry mode and riders can stare at a tree, a rock, debris on the trail or whatever, which inexorably makes the actual "pilot" of the bike aim right for that obstacle. This happens to car drivers, motorcyclists, and the term originated with airplane pilots in one of the mass killing spree "world wars" where the pilot would unintentionally kamikaze right into the target they tried to bomb.
This reminds me of post about the futility of "Expert How-To Videos". The "communication" between the "I" and the pilot is not symbolic or verbal, it's really "by feel". Now that I spent hundreds of hours on the MTB, little glimpses of "feel" come through to the "I". I'll "feel" the tire and ground interface with my feet, but that chain of communication for me is weak and inconsistent. For some people who are super experts it's constant and solid.
Really "the pilot" is like an animal companion with respect to the verbal and symbolic mode of consciousness. This is why it's very good for people to be around lots of different types of animals through their life and not turn into an urban housecat type. The urban housecat human tends to think the whole world is verbal, when hardly any of it is. The mode of communication with the pilot mode of consciousness is in its terms not in words.
