Our Mathematical Universe
Max Tegmark · 2014
"Physical reality is not merely described by mathematics — it is a mathematical structure, and this Mathematical Universe Hypothesis implies that every mathematically consistent structure exists physically somewhere, forming the most extreme of four nested levels of multiverse Tegmark proposes."
Tegmark's starting observation is that physics has always used mathematics to describe reality, but usually treats the math and the reality it describes as two different things — the map versus the territory. His hypothesis collapses that distinction: if a theory of everything is ever found and it's purely mathematical with no ad hoc extra ingredients, that suggests reality just is that mathematical structure, not merely modeled by it — dissolving the older puzzle about the 'unreasonable effectiveness' of mathematics in physics by making it not a mystery at all: math works because reality is math.
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Large Number Coincidences and the Anthropic Principle in Cosmology
"Several of the universe's fundamental physical constants appear implausibly fine-tuned for the emergence of life — but this isn't necessarily evidence of design, because any universe where observers exist to notice the constants will, by definition, have constants compatible with observers existing."