His dissertation was named: "In defence of ethical naturalism: an examination of certain aspects of naturalistic fallacy, with particular attention to the logic of an open question argument".
В 1963 он защитил в Принстонском университете кандидатскую диссертацию по теме «"In Defence of Ethical Naturalism: An Examination of Certain Aspects of the Naturalistic Fallacy, With Particular Attention to the Logic of an Open Question Arguement"» (149 страниц).