That is theology, not science. To quote Borges:
Not only was it difficult for him to comprehend that the generic symbol dog embraces so many unlike individuals of diverse size and form; it bothered him that the dog at three fourteen (seen from the side) should have the same name as the dog at three fifteen (seen from the front).
Borges – Funes the Memorious.
Being is properly a philosophical topic, as is the Causal Relatedness of Reality (material and immaterial). Soul and Form and “substance” (which substance is the composite of the dog soul and dog embryo) are also properly philosophy and never science, for physical science is the study of passive movement of matter - form is non material and is not accessible to science except via speculation about causation of the passive formation of matter in temporal succession.
The soul moves the passive material of the dog’s body past a scientist named Borges (whomever) and repeat calling the Name “Spot” finds notice and science can speculate it is the same dog being animated as a single substance.
Soul, substance, even essence, are easily reasonable and not matters of divine revelation (which also makes sense when known).
John Martin