An important theoretical underpinning of biosemiotics is the semiotic philosophy of American scientist and semiotician Charles Sanders Peirce (1839-1914) and his observation that ‘the universe is perfused with signs’. Semiotic biology was born from a similar insight, that living systems – cells, organisms, and ecologies – are not mechanical but are scaffolded by semiosis. Semiotic systems characterise life throughout. Sign relations are responsible for the efficacy of biological systems as much as they are for abstract human conceptual systems. All obey the same triadic Peircean semiotic logic. As Norbert Wiener long ago implied about information in cybernetic systems, such informational, or in living things semiotic, relations require material bearers (codes and channels), but are, themselves, immaterial. All sign relations are manifested in von Uexküllian semiotic species umwelten, and while these (including the human) are thus necessarily incomplete models of reality (there being, as Thomas Nagel has noted, ‘no view from nowhere’), sign relations nonetheless form a semiotic bridge between mind and nature, subject and object, and intentional concept and reality. This is the case for every living organism: semiotic relations bridge the supposed gap between mind and body, culture and nature, and idealism and realism. Wendy Wheeler is Professor Emeritus of English Literature and Cultural Inquiry at London Metropolitan University. She is also a Visiting Professor at Goldsmiths and RMIT in Melbourne. In 2014, she gave the first annual University of Tartu Jakob von Uexküll Lecture to the European Association for the Study of Literature, Culture and the Environment in Estonia. She is the author of four books, two on biosemiotics, and many essays on the same topic in journals and edited collections. She is on the editorial boards of several journals – New Formations, Green Letters, Cybernetics and Human Knowing, and Biosemiotics – and is currently completing her fifth monograph The Flame and Its Shadow: Reflections on Nature and Culture from a Biosemiotic Perspective.