If X had cut the world in half.

If X had cut the world in half, then G (Gravity) would collapse the world. Is this a slippery slope fallacy?

The statement "If X had cut the world in half, then G (Gravity) would collapse the world" does not appear to be an example of a slippery slope fallacy. A slippery slope fallacy occurs when it is assumed that a relatively small first step will inevitably lead to a chain of related events culminating in some significant (usually negative) effect, without clear evidence of this chain of causation.

In this case, the statement is making a direct cause-and-effect claim: cutting the world in half would lead to the collapse of the two halves due to gravity. This is a discussion of physical consequence rather than an unsupported hypothetical chain of escalating events.

However, the statement may still be subject to scrutiny from other logical and physical standpoints:

1. **Physical Impossibility**: The notion of "cutting the world in half" defies practical and physical realities, making the initial premise highly speculative.
2. **Scientific Reasoning**: Gravity, G, indeed would cause the two halves to attract and attempt to rejoin or collapse due to the mutual gravitational pull. The claim is grounded in basic gravitational theory, assuming we're discussing a simplistic model excluding other factors like the Earth's geology and dynamics.

Absence of a slippery slope fallacy doesn’t necessarily validate the premise as scientifically plausible. The main issue is more related to the practical impossibility rather than a logical fallacy in this context.

From a physics perspective: The force of gravity between two objects is the mass of object 1 x mass of object 2 x gravitational constant / distance between the objects squared. When you're determining the "compressive" gravitational force of the entire Earth it gets a bit more complex as there's a continuum of particles all acting on each other, pulling each other towards the center of mass, but same basic principle still applies.

If you were to split the Earth in half, but both halves remained in place, gravity wouldn't be affected much. If half the Earth was to disappear or fly away, gravity would be affected, as the mass would be cut in half, and the distance between any given point on Earth and its center of mass would change. However, this would not be enough to cause the Earth to collapse in the way a star collapses into a black hole - this would require the mass to increase by orders of magnitude.

However, gravity does tend to form massive objects like planets into roughly spherical shapes. "Collapse" in this case could mean that, as the material in the Earth shifts, gravity rearranges it to a more spherical shape without causing the volume to compress by an appreciable amount.

In any case, I would not consider this a slippery slope argument, as you're talking about a direct physical causation which may or may not occur based on the specifics of the scenario.