The Forgotten Planet by Murray Leinster

In all his lifetime of perhaps twenty years, it had never occurred to Burl to wonder what his grandfather had thought about his surroundings. The grandfather had come to an untimely end in a fashion which Burl remembered as a succession of screams coming more and more faintly to his ears, while he was being carried away at the topmost speed of which his mother was capable.

Burl had rarely or never thought of his grandfather since. Surely he had never wondered what his great-grandfather had thought, and most surely of all he never speculated upon what his many-times-removed great-grandfather had thought when his lifeboat landed from the _Icarus_. Burl had never heard of the _Icarus_. He had done very little thinking of any sort. When he did think, it was mostly agonized effort to contrive a way to escape some immediate and paralyzing danger. When horror did not press upon him, it was better not to think, because there wasn't much but horror to think about.