A fascinating article in the December 23, 2013 issue of The New Yorker discusses the latest research on the behavior of plants, and the disputes among scientists as to whether this indicates that plants have intelligence. In brief, the article summarizes research indicating the following: Plants can sense light, moisture, gravity, and pressure, and they use these inputs to determine an optimal growth path. In addition, plants can sense a variety of chemicals and microbes in soil, as well as chemical signals from other plants. One scientists estimates that an average plant has three thousands chemicals in its vocabulary. When plants are attacked or injured, whether by insects, animals, or humans, they produce an anesthetic. In fact, many of the chemicals we use today, from caffeine to aspirin and other drugs, were originally developed by plants as defense mechanisms against attack. Plants under attack will also emit a chemical distress signal to other plants, which prompts the other plants to initiate their own defense mechanisms (for example, plants will produce toxins that make them less tasty or digestible to animals, or they will emit signals to predator insects who will attack the plant-eating insects). Plants compete with other plants for resources, but they also cooperate with each other to an amazing degree, sharing resources with younger or weaker plants. In fact, trees employ an underground fungi to exchange resources as well as information. Scientists have jokingly referred to this exchange system as the “wood-wide web.”
Most of these observations regarding plant behavior are not disputed among scientists. What is disputed is the issue of whether or not this behavior constitutes intelligence. There is a consensus that plants do not have a central organ that performs the functions of a brain, and it is agreed that plants do not have the abstract reasoning skills that a human being would have. However, a number of scientists argue that such a definition of intelligence is too restrictive. They propose that plants do have intelligence, defined as “an intrinsic ability to process information from both abiotic and biotic stimuli that allows optimal decisions about future activities in a given environment.” Or more simply, says one scientist, “Intelligence is the ability to solve problems.” In fact, this same scientist is currently working with a computer scientist to design a plant-based computer, “modeled on the distributed computing performed by thousands of roots processing a vast number of environmental variables.” Such an attempt would build upon previous efforts to construct computers based on the information processing capabilities of slime molds and DNA molecules.
What is fascinating about this new research is that it continues a trend in human knowledge in which our initial criteria for intelligent life has had to be gradually expanded to include more and more species formerly regarded as mindless. This raises the issue: is there in fact a clear dividing line between mindless matter and intelligent life, or is there simply a continuum, with human beings having the most advanced intelligence, animal and plant life having a more primitive intelligence, and the fundamental components of matter (molecules, atoms, physical forces, etc.) having a very primitive form of embedded intelligence. In this view, the components of matter do not have consciousness in the same way that humans or animals do, but they do “know” how to do certain things. In the case of the components of matter, they may “know” only how to do one or two things, such as form combinations with other components of matter. But even this primitive knowledge is a form of knowledge nonetheless.
Viewing intelligence as something inherent in all things is part of the theory of hylozoism, which posits that the entire universe is in some sense alive. Hylozoism goes back to the ancient Greek philosophers and has been proposed at various times by different thinkers since then. The Renaissance friar and scientist Giordano Bruno was a proponent of hylozoism, among other heresies, and was burnt at the stake by the Catholic Church.
Is viewing the universe as alive and intelligent outrageous? Consider the definition of “intelligence” put forth by the scientists studying plant life: the ability to “process information” or “solve problems.” This definition actually encompasses many or most of the functions of the physical laws of the universe, according to many physicists. In their view, the universe can be conceptualized as an information-processing mechanism, a vast computer. In fact, the 19th century English mathematician Charles Babbage, who built the first mechanical calculating device and is widely known as the “father of the computer,” believed that the universe could indeed be conceptualized as an immense computer, with the laws of the universe serving as the program.
This view of universal intelligence is not the same as the traditional view of an omniscient and omnipotent being standing above the universe and directing all of its affairs — which is why Giordano Bruno was burned at the stake. But the view of a universe with an embedded intelligence existing in all things is an intriguing alternative to the view that sees a sharp distinction between intelligent beings — divine or human — and allegedly mindless matter. Rather than viewing the universe as something mindless that is acted upon by an external intelligence, perhaps it is better to conceive of the universe as having an inherent intelligence that grows more complex over time.