Each of the four fundamental forces (gravity, electromagnetism, and the strong and weak nuclear forces) has a kind of theoretical knob.

四种基本力（万有引力、电磁力、强核力和弱核力）中的每一种都有一个理论上的旋钮。

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Such theories could also explain why gravity is so weak compared with the other fundamental forces.

这些理论也可以解释为什么与其他的基本力相比，引力竟是如此之弱。

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The core of the book describes an attempt to unify the fundamental forces of matter with the force of gravity.

这本书的核心就是描述一个试图统一引力和其它基本相互作用的理论。

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But they agree that interest rates should reflect the fundamental forces of thrift rather than the whims of central bankers.

ECONOMIST: Heterodox economics

Mean reversion is one of the fundamental forces of nature and economics.

FORBES: Magazine Article

However, of the four fundamental forces, gravity is by far the weakest, and it took until 2002 before gravity's quantum nature was proven.

BBC: Neutrons could test Newton's gravity and string theory