I spoke with my father-in-law the other day; he’s been dead for several years.
No, this is not necromancy. The Bible makes it pretty clear that the dead do not come back unless God sends them. At His whim that might be a full revivification or just a temporary non-physical form. However, séances run the risk of contacting only demons who masquerade as the dead. The Bible refers to necromancers as fakes who work with a “familiar spirit” — a euphemism for someone who cultivates the assistance of a demon, knowingly or otherwise.
Recall for a moment that we live in a world of shadows, and if all you have are your fleshly capabilities, then “reality” is a dubious term. The intellect is fallen, so no one person, nor any group up to the whole of the human race, is capable of grasping the fullness of concrete reality. Nor will the nascent capabilities of artificial intelligence take us that far, because reality is not actually concrete. Even the scientists who strive to explore the real world have discovered that perception is reality, in the sense that what you experience will tend to confirm in very concrete terms what you expect. If you teach someone else what to expect based on your own experience, their mind will tend to limit their perception in the same way that you teach it. So if you assume certain things a priori, so will your students. It’s rare that people ever learn to go back and examine their assumptions, and exceedingly rare that people grow up with a conscious wonder about what they are taught.
So while we use the language of concrete certainty about things — “I know this is so” — we should be conscious of the tentativeness of everything we say. It’s your personal experience, likely shared to some degree with others, but it remains a mere working hypothesis. This is part of that “don’t take yourself too seriously” business. What you have experienced is only a subset of what’s possible.
That Western society sneers at that on the popular level is why we see so few miracles these days. Keep in the mind that the Son of God came to live among us as a mere human man. Philippians 2:5-8, when literally translated from Greek, refers to Jesus pouring Himself out of His divine prerogatives and living wholly under the Law of Moses. But it was Moses as God meant it to be understood, and all the marvelous miracles of Christ were entirely from within the promises of the Law. That includes His ability to know things outside of human perception: He read reality from the higher realm of moral insight in the heart. That’s part of the Law, too. Much of His nation had been trapped under Hellenistic assumptions and saw these works as “unnatural,” just as Western culture does, but Jesus viewed them from the proper ground of Hebrew mysticism and they were entirely natural.
Jesus also said that under the Covenant of His Blood, we would have access to even greater miracles than those He performed under the Law (John 14:11-14).
I was friends with my father-in-law before I met and eventually married his daughter. It’s not a question of knowing the man, but knowing him as he allowed me to see. That’s normal; we all tend to vary our personality somewhat depending on who’s around. We know instinctively that we have to meet folks half-way. It’s a mistake to let them control what you are, but it’s good and just to reach out to them and we should expect a reciprocation. That’s how personal moral dominion works as a part of our individual calling from God.
The memory of the man as I knew him is still alive in my soul. A conversation with that memory will be a little different once he’s no longer around to renew and refresh that experience, but it lives still in my awareness. Because of what I believe about such things, my chat at his grave site was meaningful and contained some of the same surprises that I would expect from talking to him alive. I was there in my heart-mind, so my heart filled in the blanks from what it knows of moral reality on a higher plane. And I have the assurance from Scripture that his soul in Heaven surely heard that conversation, and would be aware of far more than I was in that moment gazing at the bronze plaque on the ground.
We had a good conversation.