Emergence occurs when simple local interactions create complex global patterns that couldn't be predicted from examining the components alone—many molecules moving in particular ways eventually produce war memorials and economic policy. Different phenomena matter at different scales, with cells forming humans, humans forming communities, and interactions between levels affecting all other levels. Moving toward depth over breadth reveals how simple rules at one level create sophisticated behavior at higher levels.

Reality consists not only of reductionist ingredients like space, time, and subatomic particles, but also of life, thought, computation, and other high-level phenomena that emerge from those ingredients yet require their own explanatory frameworks. What makes a theory fundamental is its closeness to our deepest explanations, not necessarily its proximity to physics. Choosing the right level of abstraction—when to analyze parts versus wholes—determines whether you'll understand or miss the phenomenon entirely.

Simple systems give rise to complex behavior while complex systems often give rise to simple patterns—this universal law holds across domains from physics to biology to social organization. A genetic code with just four letters creates incredible diversity through self-organization, demonstrating how good simple rules generate robust complex outcomes. Fractal patterns emerge from deterministic processes, with each scale change bringing new phenomena despite identical underlying rules.

From finite components comes infinite capability—using 26 letters and agreed conventions like grammar and pronunciation, we can create any expressible thought. Digital systems enable universality because error correction allows reliable infinite-length processes that analog systems can't sustain. Jump to universality occurs when incremental improvements reach critical thresholds that suddenly enable unlimited reach, transforming systems from specific to general-purpose.