Tranquility as Nervous System Deactivation
One of the most important awakening factors—or nervous system qualities—for samādhi is tranquility (passaddhi). In the ānāpānasati sequence, the quality is invoked first for bodily activity (step four), then for mental activity (step eight).
The open secret in concentration practice is that stilling bodily and mental processes really means calming and relaxing. We can also think about this as a nervous system process, and in that language we could call it deactivation.
Tension in the body and mind is helpfully thought of as a trauma symptom where unprocessed sympathetic activation—mostly trying to mobilize out of freeze and fawn into fight or flight—is stored as bound patterns of muscular engagement and obsessive thinking. Deactivation means finding the pathways to release these bound patterns and invite the musculature and cognitive directionality to reorient to pleasant states in the here and now.
So let's look at passaddhi as being synonymous with nervous system deactivation, and how the skillful use of attention—particularly in relation to negativity bias—can help us create the conditions for the deactivation necessary for samādhi to really get going.
