In nature we find not only that which is expedient, but also everything which is not so inexpedient as to endanger the existence of the species.

The appeal of the cat lies in the very fact that she has formed no close bond with [man], that she has the uncompromising independence of a tiger or a leopard while she is hunting in his stables and barns: that she still remains mysterious and remote when she is rubbing herself gently against the legs of her mistress or purring contentedly in front of the fire.

Man has been driven out of the paradise in which he could trust his instincts.

Most people have forgotten how to live with living creatures, with living systems and that, in turn, is the reason why man, whenever he comes into contact with nature, threatens to kill the natural system in which and from which he live.

The bond with a dog is as lasting as the ties of this earth can ever be.

Most of the vices and mortal sins condemned today correspond to inclinations that were purely adaptive or at least harmless in primitive man

We had better dispense with the personification of evil, because it leads, all too easily, to the most dangerous kind of war: religious war.