This is also a tactic that is often used to imply that two theories have equal weight when they don't just because the problem at hand is not yet fully understood.

Consciousness coming from some external signal has no evidence.

Consciousness being completely self-contained within the skull and arising from a combination of chemicals, impulses, and matter within the skull is directly observable right now. And can be tested by damaging the matter, interrupting the impulses, and changing the chemistry. Adding the whole external signal idea is unnecessary.