I highlight the importance of secluding from five hindrances in meditation. They are skeptical doubt, restlessness and remorse, sloth and torpor, sense desire, aversion. In discourses on concentration, the key to access it is seclusion from those five. In AN 9:36 it reads:

Take a mendicant who, quite secluded from sensual pleasures, secluded from unskillful qualities, enters and remains in the first absorption.

In the method of watching the breath, the only reason it at some point works is because 1) the effort sustaining the mindfulness of the breath is a right effort,¹ and 2) at some point confidence develops that concenration is developing. This confidence, and thus seclusion from the hindrance skeptical doubt, is built by proxy through rounds of effort and experience eventually leading somewhere.

But rather than relying on developing confidence by proxy of a lot of effort, there can be mindfulness about ones own doubt to meditate. And then to cultivate distance or seclusion from that doubt. One develops distance of seclusion in confidence to meditate. This very effort is what leads to concentration.

1. To practice the first base of mindfulness, the breath, it isn´t just about an effort watching it. The effort to watch it can be accompanied with a hindrance, and so the watching is strenuous. To ensure the effort of watching the breath is a right effort, one can develop light contact ↩︎