We all live in the world of our perceptions; physicists may hypothesize a world with eleven or more dimensions, but we can only sense height, width, depth… and time.
Are we the only organisms that think? What is thinking? How could we determine if another species “thinks”? Another part of the question often comes up in science fiction stories, and that is what comes under the heading of a “sentient species”; all goes to the definition of thought.
My thesis here is that thought originated with organisms discovering that particular actions resulted in particular consequences, and just the natural evolutionary process, over eons of time, is all that is required for some random species to develop some form of intelligence that results in unusual consequences; I think it’s kind of nice that the species that wound up with abilities in language, thought and logic (that allows me to write this) evolved in our species.
Probably the first organisms to actually make use of a cause-effect paradigm would have been sea life, before land life evolved; this is quite open to argument, but at some point groups of atoms became structures we would call proteins, and some proteins developed into cells, and cells aggregated into organisms. These early organisms would have developed into the first time-binders, organisms that discovered a certain action resulted in better survival abilities. There seems to me to be no means of proving this hypothesis, but to some extent we can say it would be self-evident—an organism near a nutrient, if it can by some means move toward that nutrient, will have a greater survival value than an organism that cannot sense, and move toward its nutrient. Eventually, better senses, better movements, results in better survival. But an important point to keep in mind is that the sensing of, and seeking to acquire, develops along a cause-effect time-line. Sensing to be followed by an action, takes place over a period of time, inherently due to delays in chemical or electrical actions occurring in the organism. Thus, such organisms are, from the first, genuine time-binders.
As organisms develop in complexity, the simple cause-effect paradigm becomes much more highly developed. A worm’s behavior adapts to its environment; surely a worm on a concrete sidewalk does not think “where’s my dirt?” but it does have a sense to move off of the concrete.
More highly developed organisms come to have brain structures that can allow and in some sense, “understand” time. That understanding of time is again expressed in cause-effect behavior. The cat has seen or perhaps smelled a mouse behind the mousehole. It knows (whatever we might mean by “knowing”) that if it waits beside the mousehole, it probably will be able to catch a mouse sooner or later.
What is a dog “thinking” when it looks up at you and wags its tail? We tend to ascribe human emotions and thought patterns as a means of predicting the behavior of animals, and we can expect based on past observations of animal behavior, that a dog wagging its tail probably is not angry and not likely to attack. Of course, we can never know for sure what is going on in the brain of our animal companions, but we can lay out some likely scenarios, such as that the animal has come to expect a reward (the effect) as a result of the complex set of environmental factors then present (the cause), to wit, your past behavior of feeding or petting the animal, its sense (again, the time-binding) that you may repeat the actions that were previously rewarding to the animal. We can assume, based on our general understanding of physiology that actions are occurring in the dog’s brain governing its behavior. Because we believe such animals to generally not have a capability for self-reflection, rather than saying the animal “thinks”, we might see the behavior as reflexive. The animal senses the circumstances (the cause) and behaves in a certain way (the effect).
What about the instances where animals have been observed to appear sad, to have an emotional response we would almost describe as “human-like”? Recently, a television program described a study of a group of chimpanzees. A female chimp gave birth to a baby chimp, which lived with the tribe for a short while, then died. The mother chimp, for a while, carried the dead baby around with her, as though she were unable to accept the fact of the baby’s death. Is the mother’s behavior representative of an emotional response that we might liken to human feelings? And why should we consider these responses separately from “thought” or “thinking processes”?
If thought, then, simply is an enhancement of cause-effect reasoning, which can also be stretched out in time, then why should emotions be conceived as something different? We understand, and do not minimize, the mental anguish that can come with emotional loss, or the euphoria of anticipation of some triumph of some type. Yet why should we think that the complexity of human thought is something of a qualitative difference from the stimulus-response, the cause-effect of beginning thought, proto-thought of organisms much simpler than humans? All one has to do is gaze at a night sky or ponder the number of neurons and synapses in the human brain to imagine that the human thought process could be just a much more elaborate collection of cause-effect thought elements.
It may be worth pointing out that the brain, in both animals and humans, affords the capacity to plan, to set up the “cause” in order to produce the “effect”, and when the situation results in the failure to produce the “effect”, generally the initial behavior will occur less and less frequently. We do know, going back to the experiments of B.F. Skinner, that intermittent success will reinforce behavior, hence in humans, possibly creating gambling and other addictions.
This analysis doesn’t really tell us much about the complex dynamics of human behavior. Nor does it address the arguments over the hereditary-environment dichotomy (my view is that both are operative, and it’s probably not useful to argue that one or the other is most influential).