If he hadn’t grown up in an academic family, Mr. Dennett likes to say, he probably would’ve been an engineer. From his beginnings in the philosophical hothouses of early 1960s Harvard and Oxford, he had a feeling of being out of step joined by a precocious self-confidence.

As an undergraduate, he transferred from Wesleyan University to Harvard so he could study with the great logician W. V. O. Quine and explain to him why he was wrong. “Sheer sophomoric overconfidence,” Mr. Dennett recalled.

As a doctoral student at Oxford, then the center of the philosophical universe, he studied with the eminent natural-language philosopher Gilbert Ryle but increasingly found himself drawn to a more scientific view of the mind.

“I vividly recall sitting with my landlord’s son, a medical student, and asking him, ‘What is the brain made of?’ ” Mr. Dennett said. “He drew me a simple picture of a neuron, and pretty soon I was off to the races.”

In 1969, Mr. Dennett began keeping his “Philosophical Lexicon,” a dictionary of cheeky pseudo-terms playing on the names of mostly 20th-century philosophers, including himself. (“dennett: an artificial enzyme used to curdle the milk of human intentionality.”) Today, his impatience with the imaginary games philosophers play — “chmess” instead of chess, he calls it — and his preference for the company of scientists lead some to question if he’s still a philosopher at all.

“I’m still proud to call myself a philosopher, but I’m not their kind of philosopher, that’s for sure,” he said. The new book reflects Mr. Dennett’s unflagging love of the fight, including some harsh whacks at longtime nemeses like the paleontologist Stephen Jay Gould — accused of practicing a genus of dirty intellectual tricks Mr. Dennett calls “goulding” — that some early reviewers have already called out as unsporting. (Mr. Gould died in 2002.)

Mr. Dennett also devotes a long section to a rebuttal of the famous Chinese Room thought experiment, developed by 30 years ago by the philosopher John Searle, another old antagonist, as a riposte to Mr. Dennett’s claim that computers could fully mimic consciousness.