Propositional Logic in Chapter 8 of the Gospel According to Saint John

A proposition in Logic is a universal declarative sentence that is either true or false.  There are simple propositions formed exactly of a single sentence and compound propositions formed by connecting one or more simple propositions.  Most famous connectives used to create compound propositions are NOT, AND, OR, IF-THEN and IF AND ONLY IF.

Applying logical rules in writing is a powerful and effective method to convey the intended message. John the evangelist uses it effectively in his writings.  He being the theologian of the first century was influenced by the Greek Philosophy is a well known fact. Presentation of Jesus as the logos is the most famous of John’s contributions.  John creatively uses logical rules to establish who Jesus was and Jesus’ equality with God.

In chapter 8 of the gospel according to John the Apostle, there are plenty of logical constructions. John uses repeatedly ‘implication’ and its contrapositive. Here are some of them. (The verse number is mentioned at the beginning.  Verses referred here are mostly taken from http://www.catholic.org/bible.)

4. Law of Moses: If a woman was caught in the very act of committing adultery, then she is to be stoned.

7 Jesus: If there is anyone who is guiltless, then s/he can stone the guilty.

10 Jesus: If no one has condemned you, then I do not condemn you.

12 Jesus:  I am the light of the world; if anyone who follows me then s/he will not be walking in the dark and will have the light of life.

14 Jesus: If one knows where one comes from and where one is going, then one can be testifying on one’s own behalf.

17 Law: If the testimony is of two witnesses, then it is true.

19 Jesus: If one knows Jesus, then one knows the Father.

20 John: If one’s hour has come, then one will be arrested. No one arrested him, because his hour had not yet come.

24 Jesus: If you do not believe that I am He, then you will die in your sins.

28 Jesus: When you have lifted up the Son of man, then you will know that I am He and that I do nothing of my own accord. What I say is what the Father has taught me.

31, 32 Jesus: If you make my word your home, then you will indeed be my disciples and you will come to know the truth, and the truth will set you free.

34 Jesus: Everyone who commits sin is a slave.

36 Jesus: If the Son sets you free, then you will indeed be free.

39 Jesus: If you are Abraham's children, then you will do as Abraham did.

40, 41 Jesus: If you do not do what Abraham did, then you are not Abraham’s children.  (Contrapositive  of 39)

42 Jesus: If God were your father, you would love me, since I have my origin in God and have come from him and ; I did not come of my own accord, but he sent me.

43 Jesus: You do not understand what I say, because you cannot bear to listen to my words. Contrapositive of “if you bear to listen to my words, then you do understand what I say.”

47 Jesus: If someone comes from God, then s/he listens to the words of God.

48 Jesus: You do not listen to the words of God. Hence, you are not from God. (Contrapositive of 47)

50 Jesus: There is someone who does seek his/her own glory and is the judge of it.

51 Jesus:  If you keeps my word then you will never see death.

52 Jews: Abraham is dead, Prophets are dead. Does it mean that they did not keep the word of God?
54 Jesus: If one is to seek one's own glory, then one's glory would be worth nothing.