The concept of intelligence has fascinated humans for centuries. From ancient Greek philosophers to modern-day scientists, the idea of intelligence has been explored, debated, and studied extensively. While there is still much to be learned about the nature of intelligence, it is clear that intelligence is not substrate dependent.

Substrate dependence refers to the idea that intelligence is somehow tied to the physical material on which it is instantiated. This idea is prevalent in the field of artificial intelligence (AI), where the substrate is often seen as the hardware on which the AI is running, such as a silicon semiconductor or a biological neuron.

However, this view of intelligence is misguided. The physics of intelligence is no more about silicon semiconductors or neurotransmitters than the physics of flight is about feathers or aluminum. Just as flight can be achieved through a variety of means, from feathers to engines, so too can intelligence be instantiated in a variety of substrates.

The key to understanding this is to recognize that intelligence is not a property of the substrate itself, but rather emerges from the patterns of activity within the substrate. In the case of artificial intelligence, this means that intelligence arises from the patterns of activity within the hardware and software of the system, not from the substrate itself.

This is why we can build AI systems on a wide variety of substrates, from silicon semiconductors to biological neurons. In each case, the intelligence of the system arises from the patterns of activity within the substrate, not from the substrate itself. This is why AI researchers are exploring new substrates for AI systems, such as DNA, quantum computers, and even slime molds.

Similarly, the intelligence of biological organisms is not tied to the physical substrate of the brain. While the brain is certainly important for intelligence, it is not the only factor. Intelligence arises from the complex interactions between the brain, the body, and the environment.

In fact, recent research has shown that intelligence can even emerge in systems that do not have a traditional brain at all. For example, slime molds have been shown to exhibit intelligent behavior, such as solving mazes and finding the shortest path between two points. This demonstrates that intelligence is not tied to a specific physical substrate, but rather emerges from the patterns of activity within the system.

In conclusion, intelligence is not substrate dependent. Whether we are talking about artificial intelligence or biological intelligence, the key to understanding intelligence is to focus on the patterns of activity within the system, rather than the substrate itself. By recognizing this, we can explore new substrates for AI systems, and gain a deeper understanding of the nature of intelligence itself.