… It is the distinction between the prefabricated weight of history and direct experience which evokes in me the need to make things that have not been made before.
This is from ‘Weight’  in Richard Serra: Writings Interviews (1994):
… Weight is a value for me, not that it is any more compelling than lightness, but I simply know more about weight than lightness and therefore I have more to say about it, more to say about the balancing of weight, the diminishing of weight, the addition and subtraction of weight, the concentration of weight, the rigging of weight, the propping of weight, the placement of weight, the locking of weight, the psychological effects of weight, the disorientation of weight, the disequilibrium of weight, the rotation of weight, the movement of weight, the directionality of weight, the shape of weight.
[line break added] I have more to say about the perpetual and meticulous adjustments of weight, more to say about the pleasure derived from the exactitude of the laws of gravity. I have more to say about the processing of the weight of steel, more to say about the forge, the rolling mill, and the open hearth.
… The constructive process, the daily concentration and effort appeal to me more than the light fantastic, more than the quest for the ethereal. Everything we choose in life for its lightness soon reveals its unbearable weight. We face the fear of unbearable weight: the weight of repression, the weight of constriction, the weight of government, the weight of tolerance, the weight of resolution, the weight of responsibility, the weight of destruction, the weight of suicide, the weight of history which dissolves weight and erodes meaning to a calculated constriction of palpable lightness. The residue of history: the printed page, the flicker of the image, always fragmentary, always saying something less than the weight of experience.
It is the distinction between the prefabricated weight of history and direct experience which evokes in me the need to make things that have not been made before. I continually attempt to confront the contradictions of memory and to wipe the slate clean, to rely on my own experience and my own materials even if faced with a situation which is beyond hope of achievement. To invent methods about which I know nothing, to utilized the content of experience so that it becomes known to me, to then challenge the authority of that experience and thereby challenge myself.