I think the ideas [as starting point for his paintings] are based upon very obvious physical facts – notions that are also simple-minded, such as, in the 'White Paintings', wanting to know if that was a thing to do or not, or in 'Factum', wondering about what the role of accident is. Those aren't really very involved ideas.

1960s and later - 'I never thought of it as much of an ability,' (1968)