Deduction of Ought to from Is

The issue of ‘’deduction of ought to from is’’ is one of the important issues in moral epistemology. The coherence of the theories which justify moral propositions by referring to immoral propositions are based on the presupposition of the probability of deducing a (moral) ought to from is. But, a group of moral philosophers offer reasons for the impossibility of the deduction (moral) ought to from is. Using a theoretical-analytical approach, this research seeks to show it is possible to deduce (moral) ought to from is and how this deduction occurs by citing the evidence and evaluation of each of the two groups of philosophers.