Vertical and horizontal lines are the expression of two opposing forces; they exist everywhere and dominate everything; their reciprocal action constitutes 'life'. I recognized that the equilibrium of any particular aspect of nature rests on the equivalence of its opposites. Piet Mondrian
Between man and his social environment there is a reciprocal action. Men make society what it is and society makes men what they are, and the result is therefore a kind of vicious circle. Errico Malatesta
Both of these branches of evolutionary science, are, in my opinion, in the closest causal connection; this arises from the reciprocal action of the laws of heredity and adaptation. Ernst Haeckel
The human groups have been selected for the effects of their habitual practices, effects of which the individuals were not and could not be aware. Customs are mostly group properties, beneficial only if they are common properties of its individual members but referring to reciprocal action. Friedrich Hayek