Human interdependence is no more true than economic interdependence.
 Franklin D. Roosevelt, Looking Forward (1933). copy citation

Context

“Yet when these families faced facts, they discovered anew that the vital factor for self-preservation and any possible progress was the dependence of one upon the other. This realisation spurred each member of the family to the full performance of his duty to every other member. Thus courage was restored and forward-looking plans developed. Human interdependence is no more true than economic interdependence. Our economic problems, however, are simplified rather than complicated by their interdependence and the fact that economic laws are definitely man-made. I should like to repeat in practically the same words as my acceptance speech:” source