What does an empty sack will never stand up straight mean?

Answer 1

It is an old word saying that my grandfather used to say to me all the time. I have heard it said in several different cultures but mostly old world Europe. It is of significant common/simple folk wisdom and is deceptively simple but has profound social implications.

He used to say it to me first when I was very young and sitting at the dinner table. It was, presumably, as encouragement for me to eat my dinner. Suggesting that if I ate, I would grow big and strong through the "filling of my sack" (testicular puns aside now). As I got older, it was used a bit more from a moral and ethical basis, indicating that those people with empty moral characters had no substance and would not endure or prevail.

Answer 2

This phrase means that without some amount of structure or substance, something cannot maintain stability or integrity. Just like an empty sack cannot stand upright without something inside it for support. It's a metaphor for the idea that without a solid foundation or purpose, things are bound to falter.