In this thesis, I draw parallels between ecofeminist philosophy and quantum physicist Karen Barad’s proposal for a new, performative and posthumanist metaphysics in order to analyse the capacity of ecofeminist essayism to enact change in the world. The ecofeminist essayist chooses to place herself in situations where she will encounter difference, as a by-product of her activism, for example, or through her research. This is the foundation of innovation, creativity, and invention. Of becoming and change. I explore the ways in which activist-writers Rebecca Solnit and Terry Tempest Williams engage the space between philosophy and activism—an extension of the Cartesian Mind-Body problem—and how their personal, politically-situated essays can embody that elusive connection.