"Scientists know that subatomic particles and individual atoms can behave like waves, in line with the famous quantum notion of wave-particle duality. But these properties are thought to give way to classical, billiard-ball-like behaviour as particles get larger. Quantum mechanics is needed to describe how large molecules vibrate, spin and move, but the molecules themselves are seen as occupying a well-defined position at any moment."
That statement shows man's ignorance. Just where is this threshold? That's like saying that c is the absolute speed limit.