The notion as regards the stock market is that a rising ‘bear’ market causes all stocks to rise in value, even weak ones. And associated with the idea that an improved economy will benefit all participants and that economic policy, particularly government economic policy, should therefore focus on broad economic efforts.
It is often attributed to John F Kennedy in a speech which introduced this phrase to many people was given by Kennedy in 1963, when he promised the continued defense of Europe: As they say on my own Cape Cod, “A rising tide lifts all the boats.” They did indeed say it in Cape Cod; “The Rising Tide Lifts All The Boats” had been the slogan of the New England Council since 1950.