Is it wrong to conjure dead spirits?

Please explain 1 Samuel 28:15-19 in the light of Ecclesiastes 9:5.

Does this give ground for to-day’s teaching of Spiritism?

The story of 1 Samuel 28 in no way justifies the practice of Spiritism in this or in any other age.

As for Ecciesiastes 9:5, it expresses the general rule, “The dead know not anything”; the above story of the witch of Endor is the exception, by God’s special permission, as I shall seek to show. “The dead know not anything,” i.e., of what is going on on the earth, but they know what is going on where they are, as the story of the ex-rich man and Lazarus shows (Luke 16). The former and Abraham knew each other, and the former recognised Lazarus and remembered his own five brethren.

I have not the slightest doubt Samuel was really permitted by God to respond to the call. This was less, I doubt not, of a surprise to Saul the dupe, than to the witch, the deceiver. To her the attendant spirit was familiar, but she seems to have been completely taken aback by the appearance of the strange visitant that Samuel was, for “she cried with a loud voice,” and did not know him, though by some peculiar intuition she at once became aware of the identity of Saul. Samuel was a true prophet, and could foretell the morrow’s happenings, but we have no justification for supposing that wicked spirits can foretell the future.
That this response to Saul’s evil action does not justify modern Spiritism is clear, from the fact that it did not justify his own recourse to this medium, for it is specifically mentioned in 1 Chronicles 10:13 as one of the two causes of his final downfall: (i) “his transgression” i.e., in sparing Amalek, and also (z) his “asking counsel of one that had a familiar spirit, to enquire of it. And he enquired not of the Lord, therefore He slew him.” He did ask of the Lord (sha’al), as indeed of the witch, but he did so in a merely formal way in the former case and he did not enquire (dãrash) of Him, as he did of the witch; for in her case he put himself to all pains to get information. Saul knew perfectly well the distinct prohibition of Jehovah to any kind of occult practices—consulting spirits, etc. (see Leviticus 19:31; Leviticus 20:6, 27; Deuteronomy 18:9-12), and had as we know, acted thereon, till he found it convenient to transgress!