He starts out by showing the difference (not the similarity) between human and animal communication. Animal communication is holistic: it communicates the whole situation. Human language deals with the components of the situation. Also, animal communication is pretty much limited to what is evolutionarily relevant to the species. Humans, on the other hand, can communicate about things that have no relevance at all for our survival. In fact, we could adapt our language to describe a new world that we have never encountered before. The combinatorial power of human language is what makes it unique. Bickerton thinks that human and animal communication are completely different phenomena.

In fact, Bickerton believes that human language is not primarily a means to communicate but a means to represent the world. Human language did not evolve from animal communication but from older representation systems. First, some cells (the sensory cells) were born whose only task was to respond to the environment.. As sensory cells evolved and their inputs became more complex, a new kind of cells appeared that was in charge of mediating between these cells and motor cells. These mediating cells eventually evolved categories that were relevant to their survival. Animals evolved that were equipped with such "primary" representational systems. At some point, humans evolved who were equipped with syntax and were capable of representing representations (of models of models). Human language was so advantageous that it drove a phenomenal growth in brain size (not the other way around).

Bickerton then explains why he thinks that consciousness and the self. were enabled by language: language liberated humans from the constraints of animal life and enabled off-line thinking. The emergence of language even created the brain regions that are essential to conscious life. Basically, he thinks that language created the human species and the world that humans see.