In standard arithmetic, 2 + 2 = 4.
Adding two units to two units gives four. This follows from the definitions of ordinary whole-number arithmetic.
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Objects with mass attract one another gravitationally.
Gravity produces attraction between masses in ordinary conditions; its effects can be measured and predicted.
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Light travels at a finite speed.
In vacuum, light travels at exactly 299,792,458 meters per second under the modern SI definition.
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Energy is conserved in an isolated physical system.
When all relevant forms are counted, an isolated system’s total energy remains constant in the usual physical setting.
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A probability between 0 and 1 does not guarantee a single result.
A likely outcome can fail to happen. Probability describes uncertainty, not a promise about one trial.
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Correlation alone does not establish causation.
Two things moving together does not show that one caused the other.
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Classifications apply to the exact statement. They are not numerical probabilities. Review copies show proposed classifications only.