Can We Describe The Whole Universe With A Single Number?

TL;DR

Physicists debate whether reality needs 3, 2, 1, or 0 fundamental constants, with a new argument claiming clocks alone can measure everything.

Key Points

• 1.Physics currently requires 30 fundamental constants, but 27 are dimensionless. The 27 dimensionless constants (like particle mass ratios) have no units and are the same everywhere in the universe; only 3 constants carry dimensions of space, time, and energy.
• 2.Team Three argues you always need exactly three fundamental units. The speed of light (c), gravitational constant (G), and Planck constant (h) naturally define the Planck length, Planck time, and Planck energy — representing hard physical limits of the universe.
• 3.Team Two reduces the count to two constants by invoking string theory. If all particles are vibrating strings, energy is determined by string length, eliminating the need for a separate energy unit — but string theory currently has no direct experimental evidence.
• 4.Team One, the newest argument, claims a single constant suffices if clocks can measure everything. A 2010 study showed pulsar timing could derive planetary masses, suggesting all physical measurements reduce to timing, collapsing c, G, and h into one unit.
• 5.Team Zero argues zero fundamental constants with units are truly real. Any constant with units is just a human-invented conversion factor; setting c=1 in E=mc² reveals mass and energy are equivalent, making the constant itself physically meaningless.
• 6.The debate remains unsettled and spans physics, measurement, and philosophy. The 27 dimensionless constants may grow or shrink as physics advances (e.g., dark matter, cosmic inflation), and whether the question is about constants or units is itself still contested.