Solar system is chaotic
On timescales of hundreds of millions of years—periods much longer than the ones considered by Laplace—planetary orbits are chaotic. A situation that leaves Mercury vulnerable to falling into the Sun, and Pluto vulnerable to getting flung out of the solar system altogether. Worse yet, the solar system might have been born with dozens of other planets, most of them now long lost to interstellar space.
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Predictable unpredictability
The general public knows intuitively, if not explicitly, that science makes predictions, but it may surprise people to learn that science can also predict that something is unpredictable. Such is the basis of chaos.
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we have gone from not knowing the motions of the planets to knowing that we cannot know the evolution of the solar system into the unlimited future—
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在复杂系统中，由于混沌特性，个体层面的行为通常不具备可预测性。尽管量子活动是自然界的最底层机制，它对宏观现象的解释力有限，尤其在面对生命、社会等涌现性结构时更是如此。相比之下，生物学等研究复杂系统的学科更关注机制性的解释——不仅描述“现象如何发生”，更试图回答“为何如此”，即知其然，也知其所以然。
尽管如此，在特定情境中，尤其是面对具有周期性或规模性的人群行为（population-level phenomena）时，仍可通过归纳与统计手段，获得具统计意义的预测性。