Aristotle Versus the Dichotomists

Anika Prather |

Or, How I Learned To Appreciate “On the Parts of Animals”

Not just a skeleton: “causal pathways” telling us about the essence of this form of life, Ophiodon elongatus. (source)
Not just a skeleton: “causal pathways” telling us about the essence of this form of life, Ophiodon elongatus. (source)

“One should consider the discussion of nature to be referring to the composite and the overall substantial being.” - Aristotle

Come with me on a journey as I reflect on when I discovered how Aristotle wrote about each of living creature in detail in order to discover their essential being. I am reminded of Aristotle’s brief discussion on the dichotomists at the beginning of book one of the On the Parts of Animals. When I first read about the “dichotomists,” I did not understand exactly why Aristotle did not agree with their approach to researching nature. But after reading it through — and some experiences actually looking at parts of animals — I began to see the value of Aristotle’s approach.

When I reviewed the passages about the dichotomists, one main question that continued to come to mind was the following: What are they seeking to discover about the animals through this type of research? To me it appeared that their main goal was to simply place animals in groups, but to what end? Aristotle is different however. He seems to create what I like to call these “causal pathways”, where after breaking the animals down piece by piece, or shall I say part by part (hence the name of his essay, Parts of Animals), he is able to discover many things:

*the intricate design of each animal

*the purpose for the design of the animals

*glimpses of the soul or substantial being

The purpose of this reflection is to look at the limitations within the dichotomists’ way of researching living creatures and to contrast those with the discoveries of Aristotle as he closely examines the parts of animals. In doing this, I hope to truly comprehend how Aristotle’s perusal of the parts of animals is able to assist him in coming to an in depth understanding of the living creature as a whole, more so than the dichotomists.

The Dichotomists’ Methodology for Researching Animals

Chapter two of Book one seems to be the first clear mention of the dichotomists and I wondered about the following statement: “Some people attempt to grasp the particular by dividing the kind into two differences” (642b5). What puzzled me about this statement is that it seemed too simple. There had to be more to their methodology than that. It was difficult for me to see the final purpose in this kind of research on animals. As I read the rest of chapter two it seemed to me that the dichotomists mainly focus on creating two groups, for example, land dwellers and water dwellers. In the land dwellers category, you may have all types of living creatures: cows, crows, flying ants, or squirrels. Within the water dwellers category you may have the following: water buffalo, storks, mosquitoes or beavers. What I notice about this type of grouping is that species are split apart. For example, the ant and the mosquito or the crow and the stork are both from the same specie, such as bird or insect. Aristotle had many problems with this.

Aristotle must have had the same concern I mentioned at the beginning of this section. He clearly states that dichotomy is “worthless” (642b17), vacuous and impossible (644b19). Dichotomy tears apart species (642b18) and this should be avoided (10). Although I was not able to locate a statement that clarified what the dichotomists were seeking to accomplish through this type of methodology, I came to understand why Aristotle had so many issues with it. Out of the negative comments he makes about dichotomy, his concern with splitting species apart stands out to me. I wonder if by splitting specie apart does one really come to understand what makes that specie what it is. Are you able to identify its substantial being? This is what I believe Aristotle was concerned about and what he sought to accomplish through his type of research of animals.

Aristotle’s Methodology for Researching Animals

I have come to appreciate why Aristotle would title his work Parts of Animals. He states,“…it is by the figures of the parts and of the whole body that kinds have been defined” (643b9). This being said, I think that Aristotle is saying that his methodology for researching animals is to first group animals into species, based on commonalities, and within those species there may be subcategories delineating the differences within that specie of animal. These subcategories are identified after close examination of the animals’ parts. He says, “Accordingly, one should divide the one kind straight away into many” (24). Aristotle feels that dichotomy is unable to take note of the particulars of an animal by simply stopping at the creation of two groups (644al0).

Going back to my earlier example of placing animals into the groups land dwelling and water dwelling, one must ask the question, “What can be learned about the animals specifically by placing them into these two groups?” It says nothing about why they are land dwelling or water dwelling. The formation of their body such that it dwells in that particular environment is not illuminated. Aristotle seems to me to be interested in getting a very distinct and thorough understanding of what the animal is exactly and how its body is formed so that it lives out its purpose. I believe his study method was created so that he may accomplish this.

Causal Pathways

I am not sure if this term has been utilized before or has already been coined, but I think that Aristotle is seeking to develop causal pathways that are leading to something essential by using such close examination of the animals’ parts. Step by step he looks at each part, its function and makes the necessary connection in order to get to its ultimate cause. He says, “One should explain in the following way, e.g. breathing exists for the sake of this, while that comes to be from necessity because of these” (642a32–34). The previous statement represents a causal pathway to me. I wonder if this pathway can be outlined as these three stepping stones: 1) Breathing for this (why the animal breathes) 2) That (defining of breathing) 3). Comes to be from necessity because of these (listing the body parts that cause breathing to come about). He uses the statement about breathing as an example of how investigation of animals should occur. At the end of chapter one (which is right after the breathing example), he says “This then is the way of investigation, and it is in relation to these things and things such as these that one should grasp the causes” (b3). Aristotle is for some reason interested in the causes, which accounts for his creation of these causal pathways. So here I ask another question: Where do these causal pathways lead?

Chapter five begins with mentioning the term “substantial being. ” He says that there are two types: 1). Ungenerated and imperishable throughout all eternity 2). Partake of generation and perishing (644b22–24). He admits that it would be difficult to study the first kind because it is difficult for it to be knowable to us (24–28). Therefore, his main focus is on the second kind of substantial being. He says that we can know the substantial being of plants and animals, because we dwell among them (28–29). I would like to stop here, however. I feel that I must get a better understanding of what he means by substantial being. I want to do this, because I feel that the causal pathways lead to the substantial being, but before I make that assumption, I want to understand what it is. In understanding what it is, maybe I’ll come to realize why Aristotle places so much importance upon it.

First of all, I wonder if substantial being is synonymous with the soul. In order to get some clarity on this, I went back to the De Anima to see what I could discover. In the opening paragraph he says, “The knowledge of the soul admittedly contributes greatly ….to our understanding of nature, for the soul is in some sense the principle of animal life” (De Anima 402a4–6). This (principle of animal life) sounds like substantial being to me. In the very next line, he says “Our aim is to grasp, understand, first its essential nature” (7). Again, there is another term (essential nature) that I feel is synonymous with substantial being. The reason I am spending some time exploring if substantial being means soul is because of a statement Aristotle makes towards the end of chapter five, which I feel is the answer to my question: Where do these causal pathways lead? If he means soul and substantial being synonymously, then I can say that chapter five answers my question. So let me assume that they are synonymous and from here I will proceed.

To reiterate, Aristotle says that there are two kinds of substantial being and because the eternal/divine soul is difficult for us to know, he will focus on the one that has a beginning and an end. The kind of soul that he chooses to focus on is more so the nature of the animal…its substantial being…what it is….its essence and it is in studying the causes that we get a sense of its substantial being. Aristotle says, “Surely it would be unreasonable, even absurd, for us to enjoy studying likenesses of animals on the ground that we are at the same time studying the art, such as painting or sculpture, that made them while NOT prizing even more the study of things constituted by nature, at least when we behold their causes” (645a9–14). This is where the dichotomists fail. By simply putting animals in two groups, you are only observing the outer workings of the animal, but there is so much more to the animal than that! There is its essence; its substantial being (24).

Aristotle feels that in all natural beings there is something marvelous (17). What is marvelous is that the design of animals was not created in a haphazard way, but they were designed for the sake of something (23). He uses the analogy of when discussing a house. Attention will not be drawn to the bricks of a house, but the overall shape of the house will be admired. In the same way, as we study animals, we should appreciate the parts because of the whole that it creates (30–34) This is what begins to answer my question. The causal pathways are leading to the substantial being of an animal. The danger with the dichotomists methodology is that by creating the two groups there is no purpose. The only thing that is noted is the parts that are responsible for putting them in that particular limited grouping. With Aristotle, however, the soul of the animal is discovered and better understood. The importance of the parts lies in what you discover by connecting the parts.

At the conclusion of chapter five Aristotle says, “Since every instrument is for the sake of something, and each of the parts of the body is for the sake of something, and what they are for the sake of is a certain action, it is apparent that the entire body too has been constituted for the sake of a certain complete action” (645b15–17). “Complete action” is the focal point of that statement. The complete action is connected to the substantial being. Within the term complete action, is found the very purpose of the animal, I think. Aristotle seems to want us to be clear on this point, when he gives a further example, “For sawing is not for the sake of the saw, but the saw for sawing; for sawing is a certain use” (17–19). He reiterates his point once again when he says, “So the body too is in a way for the sake of the soul (substantial being), and the parts are for the sake of the functions in relation to which each of them has naturally developed” (19–20). Those functions are that which demonstrates the purpose of the animal. So in noting the parts that perform the specific function, one can get a closer look at the very soul of the animal. Thus the causal pathways, lead to the soul or substantial being of the animal.

Practical Applications of Aristotle’s Philosophy

I first read Parts of Animals while in graduate school at St. John’s College. The tutor who led us, also had us engage in dissections, which were helpful to me really experiencing what Aristotle was trying to convey. We caught animals in College Creek, located on the campus of St. John’s and we caught all types of specimens. By dissecting these specimens, repeatedly I was able to make the connection with Aristotle’s emphasis on causes leading to the substantial being. One example is taking a closer look at the animal’s teeth. Two kinds of fish that we caught were the killifish (mummichog, Fundulus heteroclitus) and the silversides (Menidia menidia). I noticed that they had a tongue and teeth. When I looked them up, I realized two things: 1) they swim together near the shores in marshes and 2) they eat crustaceans. This would account for them having teeth and a tongue in order to break through some of the hard shells of the crustaceans. Also, their mouths stretched out and I wanted to assume that this helped them with digging through the floor of the water in order to catch the crustaceans.

On another occasion, we dissected a sea bass (Centropistis striata). To my surprise, the bass had another whole fish inside of its stomach. Discovering this was timely, because I was able to notice that it also had teeth and a tongue. I wonder if a fish having these indicates that its diet is not vegetarian. The bass also has one fin at the top, unlike the fish I dissected earlier, who had two fins (split). I wonder if these fin differences have anything to do with how they live. For example, the killifish and the silversides have two fins, but also mainly eat the crustaceans along the sea shore. It doesn’t take much to capture them. On the other hand, remembering the fish that was inside of the bass’ stomach, which appeared to be regular swimming fish, I wonder if the bass has to be more streamlined in order to catch his prey, thus the single fin.

At my final dissection experience, I dissected a squid (Lolligo sp.). Staying in the same path as I have been on, I want to focus on its teeth and the eating process as well. With the squid, I was surprised to find that it also had teeth that were very hard. The squid itself is very soft, and in the midst of the soft mass of its body, I found claw-like teeth, one upper and one lower. This caused me to look into what it eats as well. I found that it eats small sea animals and fish. Therefore, it would be necessary for it to have these teeth in order to grab and break down its food.

I realize that my mainly focusing on the teeth of the fish and other sea creatures seems a bit elementary, but it is what fascinated me. One main reason is because I love fish and have kept aquariums throughout my life. All I did was feed my fish little sea food flakes. Once I discovered the little teeth in the killifish and the silversides, my interest was piqued. Consistently, I found teeth even in the sea urchins! Not all of the fish and sea creatures have teeth, but those who do I feel that it gave an indication of what their diet may be like. Also, I wonder if their diet included eating other living creatures, does it also give insight into their nature. Are they aggressive creatures? When I think of the land animals that eat other living creatures (i.e. lions, tigers, hawks, etc.) I normally characterize them as being aggressive animals. Is the same true for the sea creatures? Who would ever think of a sea urchin being aggressive? These are just some thoughts I began to ponder, and I am sure that as Aristotle began to take note of various characteristics of the animals, he did the same thing. In fact there are many examples in Parts of Animals, where Aristotle does make generalizations about the animals, based on a particular body part or viscera. One example is when he compared the sizes of animals’ hearts as well as its density. He says, “The differences of the heart with respect to largeness and smallness, and hardness and softness, extend somehow to the characters of the animals…imperceptive animals have a heart that is hard and solid…perceptive ones have a softer heart” (667al3–15).

In the same way, by looking at one part of the animal’s body I was able to make some assumptions about the overall nature or substantial being of the animal. The dissections really helped me to understand what Aristotle was seeking to accomplish through his creation of Parts of Animals. Observing the parts gave him some insight into the whole, although there is a danger in making these generalizations. One could almost fall into stereotyping animals. Aristotle disagreed with how the dichotomists took one characteristic of an animal and lumped all animals with or without that particular characteristic and placed them in the same category, disregarding the splitting of specie and the combining of different specie into one category. I do appreciate how thorough Aristotle was in researching animals, but I feel that he could also become guilty of a similar mistake as the dichotomists. The mistake would be similar in that he could become guilty of generalizing animals. I now wonder how he could have extended his research even more in order to unequivocally prove that his conclusions about each animal were correct.

By focusing on book one of Parts of Animals, I understand that Aristotle was seeking to do much more than just listing the parts of animals and their relationship to each other within the body of an animal. When I first started reading the text, I must admit that I may have had a similar mentality as a dichotomist, that mentality being not honing in on the specific characteristics of each animal and the whole picture those characteristics or body parts seek to paint. I initially failed to take notice of the actual purpose behind Aristotle’s discussion of the various parts.

Now that I have a new enlightenment upon the text, I desire to review it again and read it with reformed eyes and mentality. In addition, another question comes to mind as I think about Aristotle’s view on the causes leading to the substantial being. Earlier I mentioned his example about the saw being for the sake of sawing. He used this example in connection with how the parts of the body are for a certain and complete action (645b15–19). The question that comes to mind is the following: Who or what determined the animals’ certain and complete action? Now another question comes to mind. In knowing an animal’s substantial being can I somehow get a glimpse of its creator or designer, if there is one? Was that certain and complete action determined before the animal was created? The questions continue to come as I am sure it did with Aristotle the more engrossed he became in studying the parts of animals.

Anika Prather is an educational consultant for classical schools and teaches about the relevance of classical studies in the Black community as an adjunct professor and various universities worldwide. She is also the founder of The Living Water School (, a unique school that combines classical education and the Sudbury model. She is married to Damon Prather, an engineer and they have 3 young children. They reside in Maryland.

Anika Prather


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