Our traditional Easter Post
Several years ago my RMIT colleague Tim Fry and I had an Easter-themed op-ed in the Australian Financial Review. I have posted it before, but it is well worth revisiting.
Easter commemorates the death and resurrection of Jesus Christ – Good Friday is the day of the crucifixion while Sunday commemorates the resurrection. All four gospels are in remarkable agreement. Jesus was executed on a Friday, the day before the Sabbath. The body was removed from the cross and buried before the Sabbath. Due to a prophesy that Jesus would rise after three days Matthew tells us an armed guard was placed around the tomb. On the first day of the next week, Sunday, Mary Magdalene discovered the empty tomb – Jesus had risen from the dead. This story forms the foundation of Christianity; Jesus was crucified, died and was buried and rose again on the third day. To the modern ear, however, there is an immediate problem: Friday through Sunday is, at most, two days, not three.
A two thousand year old religion, however, is not going to be caught out on an arithmetic error. There is a simple solution: The ancients had difficulty with the number ‘zero’. The Hebrews had no such number and began counting from one – Friday was the first day, Saturday the second and Sunday the third. The idea of zero was a long time coming. In the sixth century scholars in India developed a place value system and the concept of zero. Independently, similar ideas had developed in China, Babylon and amongst the Maya. Islamic scholars adopted the Indian number system and the ideas of zero and place value spread rapidly through the Arab empire. Both the Moorish universities, and international trade, played a role in the spread of these ideas into Western society. It was not until 1202, and the book Liber Aberci by Fibonacci, that the ideas took off. Even then it was not without opposition – although mathematicians took to the ideas the Italian trading class were not so easily convinced.
It is easy to poke fun at the ancients who had little understanding of a complex notion such as zero – are we any better? Most people have an understanding of zero as being ‘nothing’, an ‘empty set’ or as a ‘place holder’. Knowing the value of zero can be trivial, or quite important. For example, knowing the value of zero would have led everyone to understand the twenty-first century began in 2001, not 2000. The value of zero has even lead to tax disputes, and a High Court case in 2000. The Australian Tax Office had argued zero was not an amount and consequently there was no time limit in amending tax returns with a taxable income of zero. Although the taxpayer eventually lost her case, the Federal Court, the full bench on appeal, and the High Court all ruled that zero is a number. The legal costs to the taxpaying public would have been enormous, while the ATO gained $4,589. Here the value of zero was quite high.
While zero may represent an empty set, it is not nothing.