Among the most recent contributions arising from Baker’s 2005 article we have Daly and Langford 2009, Baker 2009a, 2015, 2016a, 2017a, 2017b, Baker and Colyvan 2011, Saatsi 2010, Rizza 2011, Pincock 2012, Bangu 2013, Baron 2014, Marcus 2013, Tallant 2013, and Wakil and Justus 2017. We can only provide here a very short summary of the main positions. Daly and Langford side with Melia to claim that the role of positing concrete unobservables in science allows the explanation of the behavior of obs