In his challenging paper,1 Vojin Rakic argues against our claim that ‘there are strong reasons to believe’ that moral bioenhancement should be obligatory or compulsory if it can be made safe and effective.2 Rakic starts by criticising an argument that we employed against John Harris.3 ,4 In this argument we maintain, among other things, that moral bioenhancement cannot be wholly effective if our will is free in what is called an ‘indeterministic’ or ‘contra-causal sense’; that is, if our choices are not fully determined by our biology and environmental circumstances. Rakic contends that we ‘do not take into account the possibility that we can have an entirely free will that does not limit the effectiveness of moral bio-enhancement’. We can use ‘our freedom to decide to be morally bio-enhanced’.

In reply, we would like to insist that if our freedom is freedom in this indeterministic sense, we cannot use this freedom to decide to subject (and to actually subject) ourselves to effective moral bioenhancement, since this effectiveness presupposes that our will is fully determined by biological causes that this enhancement influences. If certain sub-atomic processes are indeterministic, probabilistic, we cannot make them deterministic. We cannot change the laws …