Once the capacity for concentration has been developed from the inner gaze, how can we develop the penetrating vision of Vipassana, which reveals the knowledge that two phenomena – internal or external – never manifest simultaneously, but always one after the other?
With my deep respects.
Venerable Dagpo Rinpoche: I don't quite understand your question or/and your terminology. It is important to agree on the definitions of Shamatha and Vipassana. In very summary, Shamatha (mental calm) relates to concentration and supposes having overcome five obstacles (defects of the mind) thanks to eight “remedies” and six “forces” (qualities of the mind).
Vipassana is part of analytical meditation and likewise supposes having overcome obstacles thanks to remedies and forces. Otherwise, both can relate to any object of meditation.
Generally speaking, meditation being an “inner” exercise; it uses the mental sense, not the five senses (sight, etc.). It therefore does not relate directly to an external object. An ordinary being can only have one mental perception at a time, but the object of this perception can range from the simplest to the most complex.