The vital sensation is the way the person experiences himself, it is how he is, what it is like to be him, hence his individual being or his uniqueness. There are of course many features in this uniqueness, many of them unconscious and operating autonomously. It can be compared to a whole orchestra with the vital disturbance being one instrument that is out of tune, spoiling the entire performance. Many of the instruments will be in tune though, since many facets of the patient are healthy, balanced or functional but since there is one loud, false note, the music of the person will sound distorted. If the similimum then tunes this instrument, the person can start to play his own song in a harmonious way.
But first, a few words about symbols. In my understanding (and as explained in “The Charm of Homeopathy”):