Saturday, December 22, 2012

On the Illusion of Retro-Active Causality

AKA Advanced Waves and Retarded Waves

taking ukemi

In aikido training, “taking ukemi” is the practice of falling and getting thrown, and translates as “receiving body”. Good form requires slapping the mat upon impact; it reduces the force of the initial impact. But how is it that something you do after you hit the mat can affect how hard you initially hit the mat? It seems a case of retroactive causality. Upon further examination, it would become apparent that it is simply an act of spreading the force over a longer duration of time, making it seem as if the overall impact has lessened, when in fact it has just lessened per unit time.

slapping the mat upon impact

The correct form passes the impact from the main body through the shoulder, elbow, hand, in one fluid, continuous motion. In one instance, the impact begins and ends with the body hitting the ground, whereas in another, the impact begins with the body and ends with the handslap.

In shooting a basketball, the same phenomenon occurs – having good follow-through affects the accuracy of the throw. Something done after the ball leaves your hand can change the way the ball leaves you hand. In reality, we can know that the well-prepared body can use a projected feedback loop where the anticipation of the future follow-through is readjusting the shot itself to become more aligned to the anticipated follow-through. You have to do it in order to pretend like you’re going to do it.

follow through

The final and most readily observed example is that of the dropped-and-popped phone. All the parts shoot away from the point of contact, taking with them some of the energy, thus lessening the impact on the more sensitive parts of the device. Retroactive causality it is not. The misperception of time, however, is in our blood.

when you drop your phone

More Musicological Synchronicity
OCTOBER 6, 2012


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