However, I am not convinced the schools are entirely contradictory, even with their strong claims.
For example,
- Accelerating Change school: this is mainly a (historical) trajectory claim based on positive feedback loop of technology. It does not seem to make any strong (maximum) claims about even trajectories beyond the point of strong AI.
- Event Horizon school: this is a forecastability claim that the repurcussions of AI or intelligence enhancement significantly beyond current human intelligence is unknowable until you get there.
- Intelligence Explosion school: this is a positive feedback claim that the most you can tell when human intelligence is surpassed is that further intelligence gains, be it by enhancement or AI, will feedback on itself to create further and faster change.
These claims seem to agree with each other on fundamental aspects of technology and intelligence.
In addition, in my opinion, it would not take too much imagination to combine the separate claims into a unified Singularity model.
That said, the school delineation is itself a useful tool.
http://yudkowsky.net/singularity/schools