Basic dharma theory tells me that it is definitely not possible to perceive both fingers simultaneously In MCTB (Mastering the Core Teachings of the Buddha), Daniel Ingram describes the following exercise.


  I sit quietly in a quiet place, close my eyes, put one hand on each
  knee, and concentrate just on my two index fingers. Basic dharma
  theory tells me that it is definitely not possible to perceive both
  fingers simultaneously, so with this knowledge I try to see in each
  instant which one of the two finger’s physical sensations are being
  perceived. Once the mind has sped up a bit and yet become more stable,
  I try to perceive the arising and passing of each of these sensations.
  I may do this for half an hour or an hour, just staying with the
  sensations in my two fingers and perceiving when each sensation is and
  isn’t there.


What I found most curious about this, was the assumption that "it is definitely not possible to perceive both fingers simultaneously" and that this assumption is supported by "basic dharma theory".

I understand that sensations arise and pass, but I feel like I have experienced multiple sensations simultaneously and/or the sensations of multiple body parts have formed a single sensation. I'd like to hear other people's thoughts on this.

In the form of specific questions:
I can feel tingling in all of my fingers simultaneously. Does this refute his assertion that "it is definitely not possible to perceive both fingers simultaneously"? Or am I not understanding something? I suspect the latter and am hoping to be enlightened. I'm also curious what "dharma theory" he is most likely referencing?
Thanks in advance for any response.
That's kind of an advanced book.

There are no body parts within each of our own bodily experiece, only sensation.

Unless you are a natural you can't see how fast the mind works or see if awareness arises simultaneously in the beginning. It's all a blur until we have practiced long enough.

I guess your being taught to see things as they are in your own experience. While one does this kind of practice one sets concepts aside. Ideally even Dhamma theory could be put aside when one gets the hang of the practice.