REVISED EDITION SEPTEMBER 2018 The Human and Cetacean crew of the Nantucket arrives on Earth following a dull, yet at times, frightening eight-year journey from tau Ceti. With the survival of the Cetacean species at stake, their deep, mutual trust contrasts with the distrust and fear of humanity's leaders. Unadulterated youth must resolve a deathly crisis of inter- planetary proportions. The small pocket of humanity left on tau Ceti helps Cetaceans survive in the extreme conditions of their globally changed climate. Following "Dubito", "Cogito, ergo sum" explores further the meanings of belief and denial, faith and despair, fear and hope, innocence and guilt, love and hate, against astronomical odds. Shall the meek inherit the Earth?