Plant cognition after Darwin: historical and epistemological remarks

Plant "intelligence" and "sensation" are controversial notions in contemporary botany. While some scientists argue that sensory awareness, learning, memory, communication, and possibly a kind of consciousness should be ascribed to plants, a substantial part of the scientific community dismisses such claims because of insufficient evidence and the lack of neural systems in plants. In this paper, I will examine this issue from a historical and epistemological perspective. First, I will go back to a crucial precedent that is often evoked in these debates, i.e., Darwin's remarks on plant "sensation" and "behavior" and his analogy between roots and brains in the 1880 book The Power of Movement in Plants. I will point out that the issue was already well known and controversial in the nineteenth century. I will then examine contemporary debates starting from new experiments and evidence on plant cognitive powers. I will argue that current debates are partly based on elements that have been available since Darwin, such as postulates of biological continuity among living beings and the use of analogy, leading to an epistemological contrast between the need to avoid ungrounded anthropomorphic projections and the argument that kinds of cognitive states could be realized in plants. I also finally point out that investigations on animal ethics and the revaluation of non-Western views on animism and ecology have recently been introduced into this debate to break the epistemological balance between opposing views.