# QR1.4.1. The Processor

Some suggest that the physical world is both the processor and its output:

The universe is not a program running somewhere else. It is a universal computer, and there is nothing outside it.(Kelly, 2002)

But while computers process information, most of the universe doesn’t compute anything at all (Piccinini, 2007), as the sun inputs and outputs physical events not information.

And that physical events cause processes that cause physical events is the sort of recursion that programs try to avoid. A program that inputs its own output ends up in an infinite loop that it can neither stop nor change – in simple terms, it hangs. In contrast, our universe is evolving so it isn’t locked in a loop. It follows that the physical world can no more compute itself than two hands can draw each other (Figure 1.3).

It is equally glib for physicists to talk of quantum processing occurring in our spacetime:

Imagine the quantum computation embedded in space and time. Each logic gate now sites at a point in space and time, and the wires represent physical paths along which the quantum bits flow from one point to another.(Lloyd, 1999) p172.

To embed quantum processing in a fixed space and time contradicts relativity, which doesn’t allow a fixed space or time. Whatever began our universe also began its space and time. If quantum processing did that, it can’t exist in the space and time that it created. In contrast, if quantum processing is neither physical nor embedded in physical space or time, such problems are avoided.

Is it then possible for some sort of processing to create our physical world as a virtual reality? If our universe is virtual, it must be finite, because what is infinite can’t be computed, and the evidence suggests that it is. Equally all the laws of physics must be calculable, which again they are. An abstract like pi (π) can be infinite as long as it doesn’t represent a physical thing, which it doesn’t. So, the universe could be:

• Calculable: Most scientists accept that processing could calculate physical reality based on the Church-Turing thesis, that a finite program can simulate any specifiable output (Tegmark, 2007). This is not determinism, as not all definable mathematics is calculable, e.g. an infinite series. If our world is specifiable, even probabilistically, in theory a program could output it. The idea isn’t that our universe is virtual but that it could be. This option would be falsified by a non-computable law of physics but none has ever been found. Indeed, our world has an algorithmic simplicity beyond all expectations:

The enormous usefulness of mathematics in the natural sciences is something bordering on the mysterious and there is no rational explanation for it.” (Wigner, 1960)

• Calculating: That some sort of calculating creates physical events is supported by many academics, including main-stream physicists like Wheeler, whose “It from Bit” suggests that processing (bit) somehow creates matter (it). Now processing doesn’t just model the universe, it causes it (Piccinini, 2007).
• Calculated: That processing actually does calculate physical reality is the final step, but few in physics support this “strong” view, that the physical world is just an output (Fredkin, 1990).

These statements cumulate, as each assumes the previous, so what isn’t calculable can’t arise from calculation, and what can’t come from a calculation can’t be a calculated output. It is a slippery slope, as a calculable world that some calculating causes could be calculated, in other words virtual. But while the second option, that It does indeed come from Bit, sounds good, a reality can’t compute itself. Logic reduces the above options to two: either the physical world exists by itself alone, and just happens to be amazingly calculable, or it is in fact calculated and thus a virtual reality. The physical world is either the cause or it is caused, and there is no valid middle ground.

The position taken here is that non-physical quantum processes generate all physical events.

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