So as this only point among the rest remaineth sure and certain, namely, that nothing is certaine.
Pliny the Elder (AD 23–79) Roman author, naturalist, philosopher, military commander [Gaius Plinius Secundus]
Historia Naturalis [Natural History], Book 2, ch. 7 (AD 77-79) [tr. Holland (1601)]
(Source)
Often paraphrased, "The only certainty is that nothing is certain."
Quotations by:
Pliny the Elder
For mortal to aid mortal — this is god; and this is the road to eternal glory.
Pliny the Elder (AD 23–79) Roman author, naturalist, philosopher, military commander [Gaius Plinius Secundus]
Natural History, 2.5 [tr. Rackham (1938)]