Report 64

James Austin, the author of Zen Brain, makes a distinction between external absorbtion (samadhi) and internal. He uses a fishing analogy that speaks to me as an ex fly fisherman:

"Think back to some occasion in ordinary everyday life when a critical event captured your attention. To the angler who fishes with a bobber, one-pointed absorption comes when it plunges out of sight. Only a big fish could yank it this far down! Time evaporates to a standstill during such moments. Well-coordinated movements may go on with rod and reel, but consciousness of the physical self drops far off into the background. "

I still remember the concentration on the end of the tip of a floating flyline for hours sometimes, and the electrifying shock when it suddenly straightened as a big rainbow trout started to run with your fly. The sensation still appears in dreams sometimes. Such an elemental feeling - it seemed to connect me to my human lineage of hunters somehow.

 Whereas:

"The central features of a major internal absorption include (1) no spontaneous thought; (2) an intensified, fixed, internalized awareness; (3) an expansion of especially clear awareness into ambient space; (4) the disappearance of the bodily self; (5) a distinctive closing off of all sight and sound; (6) a deep, blissful serenity; and (7) a marked slowing or cessation of respiration."

I must admit I have never had this depth of experience. 

http://www.tricycle.com/general/on-translation-the-semantics-samadhi?page=0,0