In the book ‘Utilitarian Values of Zoological Science,’ Guyer talks about the role of animals and the general zoological science in expanding human intelligence and widening of the intellectual gap of the mankind. There is also an additional knowledge put forward towards theory of organic evolution and impacts of the same in helping to develop human knowledge. The theory is appreciated for both clarifying and signifying the limits of biological sciences. The book encourages the need to encourage use of evidence when carrying out research to ensure that findings with which they come up are credible and authoritative, the author therefore sets out procedures of weighing evidence in their research works on zoology. Finally, the author explains how to gain experience through practice and shows this through his years of research in zoology. The author suggests that the science of zoology is helpful to the practical affairs of life and leads to the lusty brood of economic offspring. 

The second book ‘Dualism in Animal Psychology’ by Grace de Laguna serves to collect and present facts used in the development of comparative psychology. Grace explains that is the use of such facts that helped in the development of the concept of Animal Mind in the year 1908. Due to the great controversy regarding the topic, the author seeks to elaborate the concept of the Animal Mind and its effects in the development of human intelligence. The author uses experimental evidence to aid in understanding animal behavior to help in reading the minds of animals and how the same philosophical thoughts are helpful in understanding humankind. The author submits, in the book, that the only mind that a psychologist can know is his own and such he knows directly or immediately. However, psychologists can only know the minds of other people by asking them how they feel and think.      

References

Guyer, M. F. (1918). Utilitarian Values of Zoological Science. Science, New Series, Vol. 47, No. 1220 (May 17, 1918), pp. 477-481.

De Laguna, G. A. (1918). Dualism in Animal Psychology. The Journal of Philosophy, Psychology and Scientific Methods, Vol. 15, No. 23 (Nov. 7, 1918), pp. 617-627