Along the limestone edges of southwest Ireland, where the sea now covers what was once a walkable plain, a computer model trained on the cave art of Wales has led archaeologists to finger marks, engravings, and ochre paintings that specialists believe are at least 15,000 years old — pushing the human story of Ireland back by five millennia. The discovery is less a single revelation than a methodological argument: that absence of evidence, when it rests on absence of search, is not the same as evidence of absence. What emerges is a reminder that the past does not announce itself; it waits to be