Animals as Machines

Descartes

René Descartes (1596-1650 )

French philosopher, mathematician and scientist

Discourse on Method (1637)Part 5 discusses the nature of animals

Animals are machinesPhysically animals are very much like people: same basic design, same organs

But all mechanical function of the body, e.g. heart, lungs, muscles, can be explained as purely mechanical, like clocks or wind-up toys

The body is a machine, the soul is immaterial

Animals are bodies without souls: pure machines

“Nor will this appear at all strange to those who are acquainted with the variety of movements performed by the different automata, or moving machines fabricated by human industry … such persons will look upon this body as a machine made by the hands of God”

Because it is possible to have bodies without souls, mechanical functioning without rational intelligence, we can see that the soul is something extra, given to us by God.

God only gave rational souls to people

Evidence that animals are not rational1) Animals are not flexible in their behavior. They can be very good at one type of

task, but cannot apply their ability to a different type of task (e.g. a spider can spin a web better than any human, but it cannot use its abilities creatively)

2) Animals cannot speak:

– Even though they sometimes have the right organs required for speech, e.g. parrots

– Even human idiots can speak, so speech does not require a high level of intelligence

– Even humans without speech organs can develop a language of communication (sign language)

– Animals that are more capable in other tasks than idiots, but nevertheless cannot learn to speak

– Animals can still run around sometimes when their heads are chopped off

“There are no men so dull and stupid, not even idiots, as to be incapable of joining together different words, and thereby constructing a declaration by which to make their thoughts understood; … on the other hand, there is no animal, however perfect and happily circumstanced, which can do the like”

“This proves not only that the brutes have less reason than man, but that they have none at all: for we see that very little is required to enable a person to speak”

A Turing Test for Animals?

Descartes reliance on language to prove intelligence is a kind of Turing Test

Turing Test:

• Proposed by Alan Turing in 1950• We would know that a computer was intelligent if it could converse with

people in a way that was a indistinguishable from a human being (i.e. if the computer were hidden, a human being could not determine if they were talking to a machine or a person)

Some animals (e.g. Koko the Gorilla) have been taught sign language.

But: grammar still very primitive, vocabulary very restricted. Could not pass the Turing Test

However, the Turing Test is only a sufficient test for intelligence, not a necessary test

ImplicationsDescartes concludes that since animals are not rational, they are machines. As

machines, they have no feelings, no consciousness.

If animals are machines:

They don’t feel pleasure or pain.They have no interests.

By most accounts then, we have no direct ethical duties towards them

Indirect duties still possible (i.e. because of the instrumental value of animals):

• Duty to respect private property (animals that belong to someone)• Duty to avoid cruelty because it encourages a cruel nature in us, which might then

be expressed towards other people• Duty not to hurt the feelings of people who love animals by abusing animals• Duty to maintain the health of biosystems and nature in general, for our own good• Duty to preserve beautiful creatures, for the enjoyment of others and future

generations• Duty to preserve species that may be sources of other instrumental goods, e.g.

medicine

Is Descartes Wrong?How do we know that animals are conscious?

The problem of other minds

– who knows at what point in our evolutionary history consciousness evolved: perhaps it evolved only in hominids as a result of our ability to reflect on our own thoughts (i.e. to have higher-order thoughts)

– sleepwalkers can exhibit pain response and pain avoidance behavior without consciousness (as can amoeba and robots)