... not witchcraft. It is a natural force. No natural force is either nonexistent or irresistible. No natural force is invariably effective. Psi is not irresistible under all circumstances. It is not always effective. My rat cannot levitate cheese-crumbs weighing more than 1.7 grams. My she-dog could not make you give her dog-candy once you were on guard. When you went again into the laboratory she looked at you and wagged her tail as before. You say that you thought of the box and of opening it, but you did not. It was not even an ... — The Leader • William Fitzgerald Jenkins (AKA Murray Leinster)
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