Descartes thought that animals were "flesh and blood machines" that operated purely on instinct and did not have a soul. But he advocated for animal research to better understand human physiology. Beach argued that the study of animal behavior was a valid way to understand human behavior. Are there sufficient similarities between human and animal behavior to warrant the study of comparative psychology? Descartes thought that animal research was valid. Why did he think that if he thought animals functioned solely on instinct? In the assigned article by Beach, he reviews historical perspectives on instinct. What was the position of Beach on instinct and the value of studying behavior in non-human animals?