This response paper focuses on Baradian agential realism and some of its major concepts, such as intra-action, diffraction, and more-than-human agency; the methodology of diffraction; and the worldly applications of complex philosophical theories through “knowing in being”. Examining how Lukić and Mittner reconceptualise Alzheimer’s disease and other types of dementia (ADD) as “a different form of existence” through a diffractive methodology, various art-making praxes, and Critical Disability Studies, this essay reads their transdisciplinary enterprise as a type of materially grounded theorising—or knowing in being—that takes the ethico-political implications of such theorising seriously.