Equation 3 · Part 5 · Physics Optimizes, Evolution Satisfices: Two Kinds of Perfection
=
=
What this part means
The expressions on both sides represent the same quantity under the stated assumptions.
Its job in the formula
The equals sign connects the complete expression on the left with the complete expression on the right. Both sides must have compatible units.
Full expression→=→Article meaning
The passage around this formula
A beam of light crossing from air into glass bends at the interface by exactly the angle that gets it through in the least possible time. Pierre de Fermat stated this as a principle in the 1660s, and the consequence collapses into one line of algebra: for a ray crossing between two media of refractive index and , . Snell’s law, in other words, is not an independent fact about glass. It is what falls out of a single global stipulation — least time — applied to one path among infinitely many. Pierre-Louis Maupertuis generalized the same move to all of mechanics in the 1740s, proposing that nature always acts by the smallest possible “action,” and Euler, Lagrange, and…
Learn the underlying idea
An equals sign says that the expression on its left and the expression on its right have the same value under the stated definitions and assumptions.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.