Happy the man whom indulgent fortune allows to pay to virtue what he owes to nature, and to make a generous gift of what must otherwise be ravished from him by cruel necessity.
David HumeNo amount of observations of white swans can allow the inference that all swans are white, but the observation of a single black swan is sufficient to refute that conclusion.
David HumeFor, besides, that many persons find too sensible an interest in perpetually recalling such topics; besides this, I say, the motive of blind despair can never reasonably have place in the sciences; since, however unsuccessful former attempts may have proved, there is still room to hope, that the industry, good fortune, or improved sagacity of succeeding generations may reach discoveries unknown to former ages.
David Hume