The task on our slide was to "Draw a Venn diagram to show the relationships between: human beings, mammals and persons." The main purposes were to check how Venn diagrams work and to practice the drawing tool on the presentation app.
It was, however, also a question that I hoped would be interesting. As I said last night, it's OK if we do not agree on the answers.
diagram 1. The popular drawing |
diagram 2. Also a popular diagram |
Two diagrams tied for second most popular: one was three intersecting circles, none of which fully encloses another; the other was three non-intersecting circles. Both of these Venn diagrams had two supporters each.
diagram 3. The other popular Venn diagram |
diagram 4. Not a popular drawing |
But controversy is not a bad thing: it shows both that an issue matters people, and that further discussion by formal argument is needed.
I don't want to spend any more class time discussing it, but if you would like to, this blog is an appropriate place to continue that discussion about the relationships between the sets of things that are mammals, humans, and persons.
Diagram 3
My guess was that diagram 3. might have been a misunderstanding about how Venn diagrams work, or perhaps just unfamiliarity with the drawing tool on the slide. Diagram three says that: no humans are mammals or persons, and that no persons are humans or mammals. I think we do all agree that every human being is also a mammal, and that at least some human beings are also persons, which leaves the other three options as possible representations of the relationships between the three sets of things.
Diagram 2
Venn diagram 2. says that some human beings are not mammals, which I suspect we don't really think. Every human being I've ever met or heard of has also been a mammal. But if you think that there has been or could be a human being that is not also a mammal, please make your argument. (This could quickly become complicated, but I think there is an argument to be made for this view. However, if you want to support drawing 2. as the correct representation of the relationships between the three sets of things, you do have to make that argument. It's not something obvious.)
Which leaves diagrams 1. and 4.
Diagram 1b The anti-abortion diagram? |
If I had to guess, I would say that most people would agree with diagram 1. or a slight variation on it, 1b., where the circles for the set of humans exactly covers the circle for the set of persons; that is, a popular variation on drawing 1 says that every human being is a person, and that every person is a human being. This Venn diagram represents a common anti-abortion argument which equates abortion with murder, the killing of a human person.
And now we begin to see why it matters which Venn diagram correctly represents the relationships between mammals, humans, and persons. The different concepts behind diagrams 1. or 1b, and 4. reflect what it is thought the law should allow and not allow. Similar considerations apply to debates about the legality of euthanasia, which, like abortion, is literally a life and death issue.
Another area where it matters which is the correct Venn diagram is our diet: if some mammals other than humans are also persons, then killing them for no better reason than to turn them into breakfast or dinner would seem to be morally equivalent to snacking on some human beings, which most human persons tend to think is not in fact OK, even for those humans we might not like very much. Should we really be turning all of those animals into breakfast meat? And a closely related issue: should we really be experimenting on those chimpanzees?
As I said, it does matter which Venn diagram is the right one. So, what do you think? Think about and present your ideas in a comment or two. And as with all such complex, controversial issues, it's not a bad thing to be a unsure, to explore possibilities.
Do you think that Venn diagram 1. or 1b correctly shows the relationships between mammals, human beings, and persons, or will you support diagram 4? And most importantly, can you persuade the rest of us to agree with you? What is your counterargument against the concepts represented by the Venn diagram you disagree with?
(I've assumed diagrams 2. and 3. are no longer popular options, but if you would like to, please support one of them.)