In one of his less scurrilous poems John Wilmot, Earl of Rochester, lamented that he was “one of those strange prodigious creatures, Man,” and expressed his yearning to be “a dog, a monkey, or a bear,” instead of “that vain animal / That is so proud of being rational.” Since the days of Aristotle we’ve worn the dubious moniker of “the rational animal.” The power to reason is the “specific difference” – to use the logician’s term – that sets us apart from all other species. The most obvious manifestation of our reasoning faculty lies in language; and in fact, the Greek word Aristotle used (“logikos”) for “rational” implies the ability to engage in articulate discourse. It’s no accident that the word “dumb” denotes both speechlessness and stupidity.

For all the boastfulness of this ancient definition, a certain anxiety lurks beneath its surface. Animals may not speak – though Aesop seems to have thought otherwise – but they do communicate. For the early logic-choppers, the donkey was defined as “the braying animal.” Does the donkey’s bray, the lion’s roar, the bird’s chirp, betoken some faculty, however hidden, of ratiocination? Certainly many animals display the attributes of thought; they are capable of learning, they possess memories, they seem capable of drawing inferences, they make their wishes known. But do these spell thought in our sense?

In his lucid and witty overview, “Do Animals Think?” (Princeton University Press, 268 pages, $17.95), originally published in 2004 and now available in paperback, Clive D.L. Wynne, a professor of psychology at the University of Florida, explores this age-old question. Mr. Wynne writes a casual and snappy prose – one suspects that he is a popular lecturer – and he has a good, if quirky, eye for the telling illustration, both in words and in photographs; without technical jargon, he takes the uninitiated reader firmly through a complex thicket of fact, half-fact, supposition, and wishful thinking. If in the end he can’t answer the question his title poses, he comes about as close as we’re likely to get for the foreseeable future.

For all Mr. Wynne’s genial good sense and affable style, his is a deeply serious book, propelled from start to finish by a single, passionate concern. This is how he puts it:

What I want to know is this: Are we human beings – Homo sapiens : knowing man – alone on this planet in our consciously thinking minds, or are we surrounded by knowers whose thoughts are just too alien for us to understand? To contemplate this question is to stand, not on the edge of an abyss, but on the cusp between two abysses.

The wonderful notion that we may be “surrounded by knowers” of whose thoughts we remain unaware is one that has animated legend and fairy tale from time immemorial; this is the realm of enchantment, where the secret idioms of beasts become magically intelligible, and which extends from King Solomon to the Brothers Grimm. But the scientist’s speculations rest – or should rest – on the enchantment of fact. Mr. Wynne proves that the facts of the matter are more fabulous than anything we mere “rational animals” could imagine.

From the coded dances of honeybees to the altruism of vampire bats – with deductive chimpanzees, navigating pigeons, and voluble dolphins along the way – Mr. Wynne explores the considerable intricacies of his initial question. Like all the best professors, he likes to digress, often to delightful effect. I’m not sure that the anti-bat defenses of the noctuid moth add much to his case, but his description is fascinating. Bats hunt by “echo-location,” but shortly after it was discovered that moths could hear bat signals, it was also found that some moths actually emit ultrasound clicks of their own. These moths wait till they hear the bat switch from its searching chirps to its attacking buzz before making their own ultrasounds. These effectively stop the bat’s attack.

With such defenses, we might ask, who needs reason?

The evidence Mr. Wynne marshals indicates that animals probably don’t possess rationality in any sense comparable to ours, however well chimps, for example, might do at transitive inference problems or bees at communicating the direction, distance, and quality of a nectar source. It isn’t solely that animals lack language, but that they lack grammar; they may learn words, but they can’t string them together inventively. Animals also lack the power of empathy, a form of inferential imagination that depends upon drawing parallels.

Mr. Wynne seems a bit embarrassed by his own conclusions; but he is quick – too quick, I think – to stipulate that reason is but one evolutionary advantage among others, and he even remarks puzzlingly that “the jury is still out on the whole human experiment with language and material culture.” It is?

Sometimes, too, he introduces analogies that are persuasive but not quite apposite. The beehive may function as a single sentient organism, in which drones, workers, and queens play parts analogous to the cells in a body, but the hive’s complex functioning isn’t really comparable to the workings of a computer, as Mr. Wynne contends. The beehive, as well as the nature of its occupants, can change and adapt – as they already have – under evolutionary pressure, whereas a manmade computer, however sophisticated, will never evolve on its own.

Mr. Wynne spices his account with diverting, and occasionally lurid, anecdotes about animal researchers. I hadn’t known that the pioneering student of ape behavior, Wolfgang Kohler, had served as a German spy during World War I, tantalizing chimpanzees with unreachable bananas all the while, nor quite how batso the brilliant John Lilly, who made fundamental discoveries about dolphin communication, became in his later years. (In fact, several of the researchers and animal rights zealots Mr. Wynne describes appear distinctly less rational than their four legged proteges.) The only outstanding scientist whom Mr. Wynne does less than full justice to, in my opinion, is Donald Griffin, who first discovered echo-location in bats (and whose enthralling “Listening in the Dark” isn’t mentioned in the otherwise meticulous bibliography). Mr. Griffin argued forcefully (in his “Animal Minds” of 2001) that animals possess consciousness, but this is a position Mr. Wynne rejects, albeit hesitantly.

Mr. Wynne makes a compelling case against true rationality in animals, but he resists the temptation to reduce animals to mere “machines,” as Descartes famously did; he is too seized with wonder at the marvels of animal behavior to adopt so barren a model. In the end, Mr. Wynne prefers to accept our fellow animals for what they are, as they are.

The only hint that his heart isn’t wholly in the enterprise appears on the book’s cover, where there is a color photograph of an unusually pensive chimpanzee with his furrowed brow and meditative chin cradled in a thoughtful paw. If that ape with his sagacious gaze fixed on some distant horizon isn’t pondering a new theory of Universal Gravitation, then I’m a monkey’s uncle.

eormsby@nysun.com