Inventing the Enemy: Essays by Umberto Eco Read Free Book Online

interpreted the word
rain
and to have formed a definition of it. It needs to have been established that (a) to talk of rain it is not enough to feel drops of water falling from above (as there could be someone watering flowers on a balcony above), (b) the drops must be of a certain consistency (otherwise we would talk of mist or frost), (c) the sensation must be continuous (otherwise we would say it was trying to rain but had come to nothing), and so forth. Having decided this, we have to pass on to an empirical test, which in the case of rain can be done by anyone (all we have to do is hold out our hand and trust our senses).
    But in the case of the statement “Earth revolves around the sun,” the ways for testing it are more complex. What meaning does the word
true
have for each of the following statements?
     
I have a stomachache.
Last night I dreamed that Mother Teresa appeared to me.
Tomorrow it will certainly rain.
The world will end in 2536.
There is life after death.
     
    Statements 1 and 2 express a subjective fact, but the stomachache is a clear and irrepressible sensation, whereas when I recall a dream I had last night, I may not be sure the memory is accurate. What is more, the two statements cannot be directly verified by other people. A doctor would, of course, have certain ways of checking whether I actually have gastritis or whether I’m a hypochondriac, but a psychoanalyst would have more difficulty if someone tells him she has seen Mother Teresa in a dream, since she could easily be lying.
    Statements 3, 4, and 5 are not directly verifiable. But whether it will rain tomorrow can be verified tomorrow, whereas whether the world will end in 2536 is rather more of a problem (and here we distinguish between the reliability of a weather forecaster and that of a prophet). The difference between statements 4 and 5 is that 4 will become true or false in 2536, whereas 5 will continue to remain empirically undecidable
per saecula saeculorum.
    Now let’s consider these statements:
     
6.   The sum of the angles of a triangle is 180 degrees.
7.   Water boils at 100 degrees Celsius.
8.   The apple is an angiosperm.
9.   Napoleon died on May 5, 1821.
10.   We reach the coast following the path of the sun.
11.   Jesus is the Son of God.
12.   The correct interpretation of the holy scriptures is decided by the teachings of the church.
13.   An embryo is already a human being and has a soul.
     
    Some of these statements are true or false according to the rules we have stipulated: the sum of the angles of a triangle is 180 degrees only in the context of a Euclidean system of postulates; that water boils at a hundred degrees at standard atmospheric pressure, that is, at sea level, is true not only if we accept a law of physics elaborated through inductive generalization, but also on the basis of the definition of degrees centigrade; an apple is an angiosperm only on the basis of certain rules of botanical classification.
    Some require us to trust facts ascertained by others before us: we believe it is true that Napoleon died on May 5, 1821, because we accept what the history books tell us, but we must always recognize the possibility that an unpublished document discovered tomorrow in the British naval archives might show that he died on another date. Sometimes for utilitarian reasons we adopt an idea as true that we know to be false: for example, to find our way in the desert, we behave as if it were true that the sun moves from east to west.
    As for statements of a religious nature, we shall not say they are undecidable. If the evidence of the Gospels is accepted as historical, the proof of the divinity of Christ would be accepted as such by a Protestant. But this would not be so for the teachings of the Catholic Church. The statement regarding embryos having a soul depends entirely on stipulating the meanings of expressions such as
life, human,
and
soul
. Thomas Aquinas, for example (see the