The difference between Simulated Intelligence (SI) and Artificial Intelligence (AI) is ultimately in the means not in the end. Simulated intelligence and artificial intelligence are both approaches to solving the same problems. While artificial intelligence allows for an infinite number of possible implementations to solve those problems, simulated intelligence requires a single implementation: simulating the human brain.
The desire to create AI has existed for over 60 years, but today computers can not perform human-like information processing. A notable fact that can potentially explain the failures over the last 60+ years is that existing AI approaches have not implemented computer solutions that replicate the systems level architecture of the mammalian brain.
The goal of artificial intelligence is to deliver human-like information processing capabilities in a computer in an artificial way. Specifically, attempts to create AI have involved programming a computer in an arbitrary manner selected by an engineer to attempt to accomplish specific processing tasks. AI has been very successful in providing solutions to well defined engineering problems and will likely continue to evolve efficient solutions to hard problems. However, despite enduring efforts, computers have not been able to mimic even basic tasks that humans perform at very early ages like speech understanding, vision understanding, multi-modal sensory integration, and dynamic cognitive information processing, among many possible examples.
To date, the ultimate goal of AI engineers has not been to accurately replicate human information processing in the exact way the human brain processes information. Yet, the human brain is the only known system performing the tasks described above. The solution is not AI, the solution is mimicking the circuitry of the human brain through simulated intelligence.