A Note on Several Logic Systems - Part 03. Buddhist Catukoti

   Now, it's time to talk about Fourfold Logic. Fourfold Logic is used in both Theravada and Mahayana Buddhism.

Just as the name says , Fourfold Logic has four values for a statement. In a world of Fourfold Logic , a statement may be

1. True
2. False 
3. True and False
4. Not True and Not False.

You may see ,  the aristotlean dialectic logic and the threefold logic are integrated in the Fourfold Logic while it provides an additional fourth logic value. ( Strictly speaking , the addition of the fourth logic value has caused some reformations in the first three but I don't want to confuse the reader talking heavily on more complex matters. )

Because what I have said about the first three logic values before are roughly suitable for this situation also, it is better to explain what on earth is meant by      4. Not True and Not False.

For that, I like to take an example from the Teravada Buddhist literature . There is a book named "Milinda Prashnaya" which says the story how the buddhist monk , Ven. Nagasena Arhath Thero , won the argument with King Milinda , a Greek king , who reigned in a part of the Indian land Alexander the Great had invaded before.

In that debate , once  King Milinda asked Nagasena Thero " Who does transmigrate ? "

Nagasena Thero answered " Not the dead person nor another "

When the king asked for an explanation , Nagasena Thero said,
" King , do you think a religious verse you have learnt is the exact one the composer composed? Then is it another one?
You can't say either the verse you have learned is what the composer composed or isn't what the composer composed ".

Buddhism accepts reincarnation but rejects existence of a soul or a spirit. According to buddhism,  there is nothing that travelled from the death person to the reborn person. But reborn person is not another one too . He/She is the result of the dead person.

The concept of nullity and the number zero initially created in Mahayana Buddhism with the use of fourfold logic. When zero was introduced to western countries mathematicians and philosophers had to work a lot to get it into the two fold logic environment .

Before conclude , I would say fourfold logic is a logic system which existed even before Lord Buddha who used it to explain his teachings to the mass.