Abstract

I am interested in what main differences there are between Homo sapiens and other known terrestrial species, or (for short) between man and beast. We have a sense that we differ vastly from all the rest in some respect that is mental rather than grossly physical, but we are not agreed on what respect it is. This is my topic today. I shall bring in some work done in recent years by ethologists and animal psychologists. It is relevant less because it provides news about the beasts than because it spurs our thinking about what we already think or intuit about the beasts and how they differ from us. That is really my topic: although we don’t agree in what we say about what mainly differentiates us from the other animals, I think we have the same picture of the difference, the same sense of what it is; and I want to know whether that shared picture, or intuition, can be parlayed into an agreed description. One proper study of humankind is ourselves; that includes our thoughts, which include our thoughts about what makes us special. I shall go on talking as though the question were: What is the difference? But really it is: What difference do we already think is there? Or, anyway: What difference can be known to obtain between us and them, on the basis of what we already know about us and about them? I am interested in differences of kind rather than of degree. If the final story is merely that we are more intelligent than the beasts are, that means that our common picture of how we relate to them is false. Mortimer Adler, in his book The Difference of Man and the Difference it Makes argues for a fundamental intellectual difference of kind between humans and other animals. Having identified me in that book as an ally, on the strength of my book Rationality, he wrote to me about the matter. During the correspondence that followed, I wrote that while I agreed with his conclusion, I didn’t hold it with such passion as he did, perhaps because I was sure that the difference between kind and degree is itself a difference of degree..