Underground networks let plants communicate, implying a shared form of mind

The argument

This argument rests on the networks that link plants below ground. Root systems are joined by fungal threads through which plants exchange nutrients and chemical signals, and through which a plant under attack can effectively put its neighbours on alert. Above ground, damaged plants release airborne compounds that change the chemistry of plants nearby. Proponents describe the result as a communication system: messages are produced by one organism, travel through a medium, and alter the behaviour of another. The inference drawn is that communication of this kind implies something more than isolated reflex. A reflex is a private event inside one body. What the underground network shows, on this view, is information passing between bodies and being acted upon — the same thing that in animals we unhesitatingly call signalling, and that we take as evidence of minds attending to one another. If a forest is exchanging warnings and resources through a connected web, then the unit that senses and responds may not be the individual plant at all but the network, which would be a form of distributed mind rather than an absence of mind. Proponents accept that this picture is contested and that the mechanisms involved are chemical rather than neural. Their claim is that the distinction does the sceptic less work than it appears to: nerves are themselves chemical and electrical, and the question is what a signalling system accomplishes, not what substance carries it. Because plants are connected by networks that carry information between organisms and change their behaviour, this argument concludes, plant life exhibits a shared form of consciousness operating underground.

Premises

Counter-arguments

Critics reply that the mental vocabulary is doing the work rather than the evidence. A plant does not warn its neighbours; it releases a compound that neighbouring tissue reacts to chemically. Describing that exchange as communication borrows a word from creatures with minds and then reads the borrowed implication back out as a finding. Nutrient and chemical transfer through a fungal network is a physical process, and nothing in it identifies a subject, individual or collective, to whom the transferred information could appear.

Rejecting the premises

[Rejecting P1] That nutrients and chemical signals pass between individuals through fungal and root connections is not in dispute, and transfer through a shared medium is not by itself communication in any sense bearing on mind. [Rejecting P2] Altering chemistry and behaviour on receipt of a signal is exactly the response the opposing position attributes to automatic chemistry. The premise restates the observation in contention rather than adding anything to it. [Rejecting P3] The definition offered is met by hormones within a single body and by a smoke alarm triggering a sprinkler. That communication in animals is taken as evidence of mind rests on much else known about animals, and the premise detaches the inference from everything that licenses it. [Rejecting C] The conclusion asserts a distributed consciousness where the premises describe signal transfer. Nothing in them identifies anything for which the distributed state would be an experience.