When contact is made, by means of a switch, the electric current flows, the wire is instantly 'alive', the resistance becomes white-hot, and there is light.
When contact is broken, the current no longer passes, the resistance cools, there is darkness, and the line is 'dead'.
The electric current is what is implied by 'prajna' where sentient beings are concerned: it is the act of action, the living of life.
Nobody knows what electricity is, nobody knows what prajna is: both terms are just names given to concepts that seek to describe in dualistic language a basic 'energy' that enables appearance to appear and being to be.
When contact is made we know it as 'light' and as 'life'; when contact is broken we know it as 'darkness' and 'death'. But the source of 'energy' remains intact and intangible.
Are we the hot resistance and the light, the cold resistance and the darkness - or the vital current itself?