Distinction between Men and Animals
Throughout the novel, Wells refers to the Beast Men as "travesties" and "mockeries" of humanity. Through Prendick, he implies that no matter how Moreau or anyone else puts them together, animals are by nature animals, not men. Thus he emphasizes the qualities of humanity that exist outside of a physical body. Darwin's theory challenged this metaphysical barrier by suggesting that humans were merely exceptionally well evolved animals, and Wells appears to be trying to assert human exceptionalism. Of particular note is that what Prendick seems to find most human in the Beast Men is their constant awareness of their inadequacy. That is, they are cognizant and desirous of an ideal they are unable to reach, and this shortcoming makes them unhappy.
Montgomery provides an alternative perspective, and he introduces a degree of relativity to the issue. Separated from other men for so long, he has become much closer to the Beast Men, and he does not make as clear a distinction between them and himself as does Prendick. Perhaps as a result of the variation in Dr. Moreau's experiments, the Beast Men are not uniform in their degrees of bestiality versus humanity; besides, some animals are by nature closer to men than others are.
Dangers of Scientific Progressivism
While Moreau's actions are abominable, Wells did not create a one-dimensional antagonist. Driven by scientific curiosity, Moreau lacks compassion. This scientific objectivity is understandable, if humanly inexcusable. Even so, his actions are not purely objective; quite the contrary, they result from his overpowering desire to cause scientific "progress." This dangerous motivation is more familiar to readers than a simple impetus to cause harm.
Despite his socialism, which relied on a hope in social progress through the use of reason, Wells was tapping into a common concern about the amoral march of "progress," namely the risk that it can corrupt and overwhelm the natural sensibilities of men with its promises of shiny, efficient perfection. Many people in his time worried that man was overstepping his authority and entering the domain of divinity. Moreau's vivisections express the dangers of science and technology. Doctor Moreau's speech to Prendick in defense of his activities is especially relevant: as a man of reason he claims, among other things, that pain and pleasure are irrelevant.
Class and Government
As in his earlier work, The Time Machine, Wells plays with class expectations and distinctions. His protagonist, an educated and rich gentleman, finds himself quite useless among the crude practicality and simplicity of the island community. The bulk of this society consists of Moreau's created race of subhumans (representing the exploited underclass), with Moreau as dictator and Montgomery as second-in-command. The events of the story provide an unflattering account of authoritarian rule. Remembering Wells's class sympathies and his later communism, one could take the novel as an indictment of social stratification in general. The Beast Men even take a Marxist revenge toward the end of the story--a universal uprising against their rulers that results in the death or expulsion of all authority figures. At this point, though, their choice of reversion to bestiality allows them to escape the constraints of Moreau's imposed humanity.
The Law as Religion
The injunctions and prohibitions that Moreau ingrains in the minds of his creatures are known collectively as the Law, and they are what bind the Beast Men to Moreau's vision of vivisected humanity. But because they have no memories of past lives before Moreau's operating table, the Beast Men's belief in their humanity is based almost entirely on faith. In that sense, their quest for humanity is comparable to the spiritual purity sought by followers of many religions; we believe that we are meant to be something more than we are today.
The Law is, as it is referred to several times in the narrative, a litany. Also significant is the actual recitation of the Law, which is analogous to the fervor of many religious rituals. That is, when the Beast Men call out the Law, they regurgitate the text as an incantation, rocking back and forth and beating a rhythm off their bodies and their surroundings. The Sayer of the Law then functions as their priest, uniting the community in a theocracy defined by Moreau's idea of what separates men from animals.
Confusion and Constraint
Because Wells writes from the first-person perspective of Prendick, the reader never grasps the full details of events unless Prendick does so himself. This confusion reflects the natural imperfections of a narrator who is not omniscient. It is augmented by the vague details of Montgomery's and Moreau's past, the blurry philosophical muddle of the Beast Men (who are neither beasts nor men, but who are also both beasts and men), and the uncertain prospect of rescue. Most of Wells's characters are thus stripped of their ability to alter the world according to their own desires and beliefs, being reduced almost to driftwood, carried helplessly along by the current of events. Just to get oneself to the point of independent revolt is a feat.
This is a method of inspiring bleakness and despair among readers, who come to feel as ineffectual as Prendick. After all, readers have no way to alter the events; the best we can do is to try to think through an objective account of events as though it were not mediated by Prendick. This world also suggests that man is not the center of his universe; even Moreau ultimately fails to control everything on a single island. Individuals always must be constrained to some degree by society and circumstance.
At worst, however, natural circumstances are neutral, not malicious. It is a chance meeting with a ship that saves Prendick's life (twice, in fact). In other words, for better or for worse, nature will take its course, and a scientist tries to minimize confusion about the natural world by understanding its patterns.
Biblical Analogies
Just as the Law resembles religious commandments, the inhabitants of the island are analogous to certain elements and characters of the Bible. For example, Moreau represents God with his stereotypical white hair and beard, unquestioned authority, ability to make new creatures, and role as distributor of pleasure and punishment. But he is not a true Creator in the biblical sense in that he cannot create the human form, nor even can he imitate it perfectly. He aspires to be God but produces only monsters.
Montgomery occupies the place of Christ in the island universe. With a sheep-like face, a fondness for both the Beast Men and men proper, and certain messianic tendencies (such as his fatal attempt to finish Moreau's work by feeding the Beast Men brandy in a twisted sort of communion), he is the bridge in the religious hierarchy. And the serpent of Eden is figured in Moreau's description of a snake-like "failed experiment" that terrorized the island before Montgomery finally destroyed it.
