In folding in time, Eisenman rejects the mathematical model of the Cartesian rationalism. He explains that we have entered a new era of mediated environments and experiences in which past architectural expressions such as brick and mortar, structure and foundation, are no longer relevant. He replaces these ideas with Deleuze's and Thome's theory of "the fold" in which new relationships between vertical and horizontal, or figure and ground create a continuous space breaking up the Cartesian order of space and experience as it has been previously defined.