Johan E. Gustafsson

In this paper we shed new light on the Argument from Disagreement by putting it to test in a computer simulation. According to this argument widespread and persistent disagreement on ethical issues indicates that our moral opinions are not influenced by any moral facts, either because no such facts exist or because they are epistemically inaccessible or inefficacious for some other reason. Our simulation shows that if our moral opinions were influenced at least a little bit by moral facts, we would quickly have reached consensus, even if our moral opinions were affected by factors such as false authorities, external political shifts, and random processes. Therefore, since no such consensus has been reached, the simulation gives us increased reason to take seriously the Argument from Disagreement. Our conclusion is however not conclusive; the simulation also indicates what assumptions one has to make in order to reject the Argument from Disagreement. The simulation algorithm we use builds on the work of Hegselmann and Krause (J Artif Soc Social Simul 5(3); 2002, J Artif Soc Social Simul 9(3), 2006).

One of the principles on how to act under moral uncertainty, My Favourite Theory, says roughly that a morally conscientious agent chooses an option that is permitted by the most credible moral theory. In defence of this principle, we argue that it prescribes consistent choices over time, without relying on intertheoretic comparisons of value, while its main rivals are either plagued by moral analogues of money pumps or in need of a method for making non-arbitrary intertheoretic comparisons. We rebut the arguments that have been levelled against My Favourite Theory and offer some arguments against intertheoretic comparisons of value

In the 1960’s, Lars Bergström and Hector-Neri Castañeda noticed a problem with alternative acts and consequentialism. The source of the problem is that some performable acts are versions of other performable acts and the versions need not have the same consequences as the originals. Therefore, if all performable acts are among the agent’s alternatives, act consequentialism yields deontic paradoxes. A standard response is to restrict the application of act consequentialism to certain relevant alternative sets. Many proposals are based on some variation of maximalism, that is, the view that act consequentialism should only be applied to maximally specific acts. In this paper, I argue that maximalism cannot yield the right prescriptions in some cases where one can either (i) form at once the intention to do an immediate act and form at a later time the intention to do a succeeding act or (ii) form at once the intention to do both acts and where the consequences of (i) and (ii) differ in value. Maximalism also violates normative invariance, that is, the condition that if an act is performable in a situation, then the normative status of the act does not depend on what acts are performed in the situation. Instead of maximalism, I propose that the relevant alternatives should be the exhaustive combinations of acts the agent can jointly perform without performing any other act in the situation. In this way, one avoids the problem of act versions without violating normative invariance. Another advantage is that one can adequately differentiate between possibilities like (i) and (ii)