Another approach, instrumentalism, emphasises the utility of theories as instruments for explaining and predicting phenomena. It views scientific theories as black boxes, with only their input (initial conditions) and output (predictions) being relevant. Consequences, theoretical entities, and logical structure are claimed to be things that should be ignored. Close to instrumentalism is constructive empiricism, according to which the main criterion for the success of a scientific theory is whether what it says about observable entities is true.
aNOthEr AppRoach, iNStrumEntalism, empHasises The uTiliTy of THEorIEs As instrUmENts foR eXPlAininG anD predictINg Phenomena. it ViEWs scIentiFIc theorIeS as blacK bOxEs, with Only thEIr inpuT (InItial CONDiTioNs) ANd ouTput (predictioNs) beiNG relevAnt. cOnseQuenCes, theoretICal eNTiTiEs, aND loGicaL STRuCTure Are cLAimed tO be tHINgs ThAt shoUld be IgNoreD. ClOse To INSTRumentAlisM is coNstRUctive empIRiCiSm, accOrdIng to wHicH The mAIn CriTeRion foR thE success oF a sCientific thEOry iS whEthEr whAT it SayS aBoUt obServabLE entities is TruE.