Robinson Crusoe Extract

Had I now had the sense to have gone back to Hull, and have gone home, I had been happy, and my father, as in our blessed Saviour’s parable, had even killed the fatted calf for me; for hearing the ship I went away in was cast away in Yarmouth Roads, it was a great while before he had any assurances that I was not drowned.

But my ill fate pushed me on now with an obstinacy that nothing could resist; and though I had several times loud calls from my reason and my more composed judgment to go home, yet I had no power to do it. I know not what to call this, nor will I urge that it is a secret overruling decree, that hurries us on to be the instruments of our own destruction, even though it be before us, and that we rush upon it with our eyes open. Certainly, nothing but some such decreed unavoidable misery, which it was impossible for me to escape, could have pushed me forward against the calm reasonings and persuasions of my most retired thoughts, and against two such visible instructions as I had met with in my first attempt.

Questions:
Why does he not have the courage to return home?
Why does continuing his journey is deemed as well as going for his doom?

Ebook link: http://www.planetpdf.com/planetpdf/pdfs/free_ebooks/Robinson_Crusoe_BT.pdf

(line 15 pg 19 - line 9 pg 20)