Code and Circuits in 4D Spacetime
October 12, 2020

Code and circuits occupy spacetime. Every logic result happens at a place and time, every stored bit persists through a physical mechanism, and every connection consumes route length, delay, surface access, and interior volume.

State Becomes a Path Through Spacetime

A source program describes values and transitions. A circuit realizes them as events linked through wires, gates, storage elements, and timing relationships. What software calls state appears physically as structure that carries information from one time slice to the next.

This four-dimensional view turns memory and logic into one connected geometry. A register, feedback path, or persistent field extends information through time; combinational logic transforms it across space.

Boolean Algebra Gains a Physical Body

Boolean algebra can describe the switching relationships required for universal computation. A physical realization adds placement, propagation, restoration, gain, fanout, and synchronization. The equations express what can connect; spacetime determines how the connection operates.

Universal Computation With Multiplexers develops the selector as the elementary logical mechanism and follows that mechanism into a spatially configurable machine.

Volume Creates Opportunity and Cost

As a computer grows, interior volume grows faster than exterior surface area. The extra interior can hold immense parallel structure, yet communication with the outside and across long internal distances cannot scale the same way. Architecture must therefore place computation near state and give local structure meaningful autonomy.

Draw the next program as a spacetime circuit. Show where information lives, when it changes, how far it travels, and which physical structure owns the transformation.

Originally posted on LinkedIn

Brian Greenforest · (2020-10-12 17:54:17 UTC)

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Are you a neural networks training data scientist? Are you a programmer writing an object-oriented code? Are you a hardware design engineer? Study general relativity, and start thinking about time as a spatial dimension in your code and circuits. Why? State disappears. Boolean algebra is Turing-complete in 4D spacetime. (I need to add that I oppose pure functional programming, because for any given number of inputs, in a _physical device realization_, there's much more volume inside. Simply said, FP doesn't scale because surface area grows much slower than volume of a computer.)