The world can be classified in different ways,

depending on one's interests and principles of clas-

sification. The classifications (also known as

Line

taxonomies) in turn determine which comparisons

5

seem natural or unnatural, which literal or analog-

ical. For example, it has been common to classify

living creatures into three distinct groups—plants,

animals, and humans. According to this classifica-

tion, human beings are not a special kind of

10

animal, nor animals a special kind of plant. Thus

any comparisons between the three groups are

strictly analogical. Reasoning from inheritance in

garden peas to inheritance in fruit flies, and from

these two species to inheritance in human beings,

15

is sheer poetic metaphor.

     Another mode of classifying living creatures is

commonly attributed to Aristotle. Instead of treat-

ing plants, animals, and humans as distinct

groups, they are nested. All living creatures

20

possess a vegetative soul that enables them to

grow and metabolize. Of these, some also have a

sensory soul that enables them to sense their envi-

ronments and move. One species also has a

rational soul that is capable of true understanding.

25

Thus, human beings are a special sort of animal,

and animals are a special sort of plant. Given this

classification, reasoning from human beings to all

other species with respect to the attributes of the

vegetative soul is legitimate, reasoning from

30

human beings to other animals with respect to the

attributes of the sensory soul is also legitimate,

but reasoning from the rational characteristics of

the human species to any other species is merely

analogical. According to both classifications, the

35

human species is unique. In the first, it has a king-

dom all to itself; in the second, it stands at the

pinnacle of the taxonomic hierarchy.

      Homo sapiens is unique. All species are. But

this sort of uniqueness is not enough for many

40

(probably most) people, philosophers included. For

some reason, it is very important that the species

to which we belong be uniquely unique. It is of

utmost importance that the human species be

insulated from all other species with respect to

45

how we explain certain qualities. Human beings

clearly are capable of developing and learning

languages. For some reason, it is very important

that the waggle dance performed by bees ^* not

count as a genuine language. I have never been

50

able to understand why. I happen to think that the

waggle dance differs from human languages to

such a degree that little is gained by terming them

both "languages," but even if "language" is so

defined that the waggle dance slips in, bees still

55

remain bees. It is equally important to some that

no other species use tools. No matter how inge-

nious other species get in the manipulation of

objects in their environment, it is absolutely

essential that nothing they do count as "tool use."

60

I, however, fail to see what difference it makes

whether any of these devices such as probes and

anvils, etc. are really tools. All the species

involved remain distinct biological species no

matter what decisions are made. Similar observa-

65

tions hold for rationality and anything a computer

might do.