Why did Robinson Crusoe consider himself half-dead and half-alive? When he said'' and myself almost dead''

In Chapter
IIInarrates that he has a prosperous cane and tobacco plantation; however, he cannot be content,
but feels that he must leave and

pursue a rash and
immoderate desire of rising faster that the nature of the thing admitted.

And so, he casts himself into "the deepest gulf of human
misery" when he signs on with fourteen other men who set sail for Guinea in pursuit of
slaves for their plantations. For, when they are near the coast of St....