Arguments from underdetermination take two forms, those from global sceptical underdetermination, global scientific underdetermination and local underdetermination. Arguments from global sceptical underdetermination bring into question all knowledge, they develop sceptical scenarios that purport to show that we cannot trust any ‘knowledge’ that we obtain within the world. Arguments from local underdetermination aim to bring into question the nature of our knowledge and are geared against scientific realism. This thesis is an evaluation of the arguments that claim to do the latter, however it shows that these arguments are not arguments from local underdetermination but are from a type of global underdetermination that I call global scientif...