Jesus makes 3 claims connected by the conjunction και. Each one has the definite article. Jesus claims to be "the way" (η οδος), "the truth" (η αληθεια) and "the life" (η ζωη). An article is commonly attached to an abstract noun in order to point back to what has already been mentioned. This is called an "anaphoric" use of the article. The article in "the way" fits the anaphoric use because Jesus is answering the question by Thomas in the previous verse. The article points back to that question. However, the other two articles cannot be anaphoric since there is nothing in the context about "truth" and "life." What do these articles tell us about Jesus in this classic assertion of Christianity?
The verb ειμι is an equative verb. The 3 assertions are predicate nominatives. An article is used with a predicate nominative to assert that the subject and the predicate nominative are identical. The verb equates the subject with the predicate nominative. The article specifies that the subject and predicate nominative are "convertible" (Robertson, Grammar, p. 768).
I = way and way = I
I = truth and truth = I
I = life and life = I
Jesus makes 3 radical claims. He, personally, is the only way to the Father as the next clause makes clear. Jesus also claims that he, personally,is the essence of truth and the embodiment of life. "I am the only way to the Father because truth and life are wrapped up in me personally! To know me is to know truth and experience life on the way to the Father!" What man can make that claim without being considered cuckoo?