Questions About The Melting Clocks

Sometimes referred to as just the "melting clocks" painting, in Dali's The Persistence of Memory (1931) a mysterious human-like white figure sleeps in an otherwise deserted landscape

A clock covers the sleeping figure's back, almost the same way a blanket might cover a sleeping child. Nearby, another clock drapes over a limb. While we usually think of clocks as hard, unbending objects, Dali's clocks are flexible, malleable things that seem to be soft, perhaps melting away in the desert sun. What do these melting clocks mean? Why are they laying out there in the sun? What is the hidden meaning?