Taxonomy (Or Why Modern Biological Categories are Wrong)

cladeAristotle was the first to systematically lay out various living things in the world. According to him, they could be divided into three categories: plants, animals and rational beings (humans). Insofar as biology is concerned, human beings are animals. Therefore, there were two biological categories: plants and animals. Carl Linnaeus extended this knowledge to cover many new kinds of plants and animals, and created more divisions below that of plants and animals. Many of our modern biological categories come from him. The highest division was the kingdom and there were two kingdoms: plants and animals. In 1866, Ernst Haeckel suggested that simple single celled organisms form a third kingdom that he originally called Monera. (He later called this kingdom Protista.) His reasoning behind this change was that biological divisions show historical ancestry (common descent). Modern taxonomists have followed this new pattern and begun a program of categorizing biological things according to ancestry. This is wrong because it is contrary to the purpose of biological categorization.

There are thousands and thousands of different kinds of biological things. There are also many possible ways to categorize them. We might categorize living things by considering how we use them. So weeds refer to plants that we do not want, trees refer to large plants that provide shade, vegetables are edible plants with a similar kind of taste and fruits are plants that have sweet parts. This kind of categorization does not help us understand the living thing. It simply helps us categorize the living thing according to our purposes for it. In fact, any external categorization will not help us understand the living thing. I might name plants according to where they are found, whether I like them, where I bought them or what they can be used for. But these things may vary even if the plant (or animal) stays the same. Furthermore, even if these things do not vary, the explanation for why they do not vary includes knowledge not related to the living thing in question. For example, the reason why pineapples are edible partially has to do with the human digestive system. Finally, even the knowledge about the living thing itself does not unify our knowledge of that living thing. So no externally based categorization scheme is proper if our goal is understanding the living thing itself.

Categorizing living things by their ancestry is an external categorization scheme. The explanation why two living things were placed in the same category would be an external fact (that it is the best fit for those two individuals given the rest of biology). Although historical knowledge is invariant across researchers, it includes both facts about the living thing itself and facts about the rest of the living things that happen to live in the world. Secondly, knowing that dogs and wolves share a common ancestry does not unify our knowledge of dog or wolf biology. Knowing that both dogs and wolves are mammals (and that being mammalian is more fundamental than being a dog or a wolf), does unify our knowledge of either a dog or a wolf.

When we categorize living things we must begin with what is most fundamental, and work our way to what is least fundamental. What is most fundamental to a living thing is the reason why it is alive. Without that, it would not be a living thing at all. Everything else that a living thing does supports the life of that living thing first of all. Least fundamental are the parts of the living thing that can change without harm to that living thing – such as the length of hair, the color of hair or the growth of new branches. Nowhere in this scheme is there room for facts about the ancestry of living things.

The purpose of categorizing living things in biology is to organize them in order to understand them in themselves. The purpose requires categorizing living things according to differences in those living things beginning with the most fundamental differences. Since the differences between living things are purely internal, there is no room for history. Therefore, classification schemes such as cladistics that are based on historical relationships between organisms are universally wrong.


In my two previous posts, I have explained the content of both applied and normative ethics. The last division within ethics is metaethics. Remember that applied ethics applies a normative ethics theory to a particular productive or active science while normative ethics asks how we determine what is right or wrong in general. Metaethics asks all of those ethical questions that normative and applied ethicists do not answer. Metaethics answers questions about the nature of goodness.

The first question is whether or not goodness can be defined, and if so, what that definition is. This has had many answers throughout history. While some have claimed that goodness was identical with pleasure, others claimed it was identical with preference-satisfaction, power, utility or God’s will. Still others have denied that goodness is capable of being defined at all. This question also asks what is good for human beings as such, and how that varies.

The second question deals with our knowledge of goodness. Positions on this have varied as well. Some believe that knowledge of goodness requires analysis while others believe that it is self-evident. Still others believe that our knowledge of goodness depends on our character or our circumstances. Still others think that it depends on how well we understand rightness in general. Whether goodness or rightness are ultimate is yet another question.

Depending on the answers to the questions above, either naturalism or non-naturalism will be affirmed in ethics. Non-naturalism need not be a form of supernaturalism, it simply needs to deny mechanism. One form of non-naturalism is found in Aristotle and in the doctrine that natural things all have purposes. Another form of non-naturalism is found in divine command theory. Still another form of non-naturalism is found in Platonic ethics. Which one of these four positions is correct is also a part of metaethics.

We also know that we are obligated to do what is good and avoid what is evil. But why? What is the nature of obligation? If we have answered the previous questions, then we will be able to determine what options exist at this point. Usually, the field is understood through the assumption that everyone believes in naturalism and therefore in mechanism as well. If we take this route, then our reasons to act morally in a certain case are either desires, beliefs or some combination. They are either reasons that we must always follow, preferably follow or they are one reason among many. We are also motivated to act morally. What is this? Is it because morals are desires, because morals are for our own good or it is motivationally basic. Still other questions may follow.

Finally, metaethics may assume principles found in metaphysics generally – particularly the philosophy of human nature. So questions of responsibility and freedom are obviously relevant to this situation. Metaethics is a quagmire of debates.

Since my point here is to understand ethics, I think that this provides a good summary of the science of ethics.