 Previous authors ( Kristjánsson cites Joel Feinberg , Alan Wertheimer and Robert Nozick ) provided moral and statistical analyses of various thought experiments to determine whether the proposals they involve are threats or offers . On Kristjánsson 's account , by contrast , all of the thought experiments considered are throffers . Instead , he argues , the previous thinkers ' analyses attempted to differentiate offers that limit freedom from those that do not . They conflate two tasks , that of differentiating threats and offers and that of differentiating freedom @-@ restricting threats from non @-@ freedom @-@ restricting threats . He concludes that the thinkers ' methods are also inadequate for determining the difference between freedom @-@ restricting and non @-@ freedom @-@ restricting threats , for which a test of moral responsibility would be required . 
