In spiritual Energy, published in 1919, and brings together conferences that start with the century, will be a first intuition of Bergson that organizes its course: it must exceed the data of the real (read, their cut, their appearance). However, in the antipodes of idealism Platonic type, that is not beyond find over reality, archetypes or always transcendent, but underneath, in the depths of the real itself, in its virtual immanent ideal forms.
From that first intuition, Bergson shows such duplicity (deployment of a uniqueness) acting in the most diverse phenomena: moral, intellectual life, memory ... says Bergson, our present existence, as it unfolds in time, and doubles with a virtual existence, perception and memory side by side.
But they also appear in this book experiences as sleep, memory disorders, false recognition (the famous "remember this"), including telepathy (communication distance between consciences through emotion). We produce electricity at all times, the atmosphere is constantly electrified, magnetic currents circulate between; yet millions of men have lived for thousands of years without suspecting the existence of electricity. We could also pass without realizing, next to telepathy.

All refers to this spiritual energy, inhibited constantly in our everyday life (inhibition favored even by our own biological data) but always present in what we are (still is not) while participating in a fundamental emotion, a vital boost. In this sense, there is to explain the spiritual energy is not so much why it appears sometimes a ghost, but why not always appear as it is always there.