In a dream, the Bible says, Jacob saw a ladder reaching up to Heaven, with the angels of God ascending and descending upon it, like a kind of celestial escalator. Jacob's ladder is remembered in popular names for the effect created by shafts of sunlight passing through rain clouds, and for a perennial garden herb with ladder-like pairs of leaves.
Maybe the ladder's spiritual leanings have some foundation in physical fact. When scientists discovered the form of DNA, the building block of all life, they found that its double helix was made up of distinctly ladder-shaped molecules.
But Jacob's vision fixed the ladder's symbolism as a kind of stairway to heaven, and inspired the board game snakes and ladders. Originally an Indian game called moksha patamu, it pitched vice against virtue on the roll of a dice, and the first player to arrive at square number 100 reached "nirvana". When it was imported as a Victorian parlour game, the meanings were altered so that anyone landing on "penitence", "thrift" and "industry" was rewarded with a leg up to "grace", "fulfilment" and "success".
Without a ladder, bunk beds, diving boards and tree houses would be out of reach, window cleaners, builders, firemen and fruit-pickers would have a much more difficult job, and DIY enthusiasts would be grounded.
But, despite its basic construction and working-class credentials, the ladder has become lumbered with associations of upward mobility, a metaphor for career advancement and a means of social elevation, from the time Shakespeare wrote of "young ambition's ladder" to Tony Blair's talk of "ladders of opportunity".
Echelon, the word associated with elevated status, comes from the French word for rung, while the Greek word for ladder - clima - is where we get the word anti-climax, literally to come down a ladder perhaps, because what we hoped to find at the top of it was not there.
Superstition dictates that walking under ladders is bad luck, and while there's always the chance that someone might drop a bucket on your head, there are more fateful explanations for this belief. Some say it is because a ladder propped up against a wall resembles a gallows and walking through it presages your death. But there's an easy way to cast off its fateful implications - just keep your fingers crossed until you see a dog.