I am a big fan of ghosts, of guides, of the idea that nothing is ever really destroyed (not the soul, not the memory, not the instinct for a skill). And since none of it can be proven one way or the other, the only question to ask yourself is what belief makes your life richer, more joyous, safer, more heart-centric? That quality-of-life belief is your truth.
So, yes, when I'm pruning roses and I hear my grandfather reminding me to cut away only last year's growth, or I hear my grandmother in the stirring of a spoon against a cup of tea, I'll take it as my proof that something lives on somewhere. I welcome the ghosts for their quiet company, for their reminder that I am not a random collection of electric connections doomed to fraying and winking out, but something guided and intelligent, humbly and reassuringly deliberate in the grand scheme of things.
I am, we are, self-sustaining energy.