▁would ▁seem ▁to ▁be ▁at ▁odd s ▁with ▁early ▁e pi phen omen al ism , ▁which ▁according ▁to ▁H ux ley ▁is ▁the ▁broad ▁claim ▁that ▁conscious ness ▁is ▁" comple t ely ▁without ▁any ▁power … ▁as ▁the ▁steam - wh ist le ▁which ▁accompan ies ▁the ▁work ▁of ▁a ▁locomot ive ▁engine ▁is ▁without ▁influence ▁upon ▁its ▁mach in ery ". ▁ ▁Ad rian ▁G . ▁G ugg is berg ▁and ▁Anna ï s ▁M ott az ▁have ▁also ▁challeng ed ▁those ▁find ings . ▁ ▁A ▁study ▁by ▁A aron ▁Sch urger ▁and ▁colle agues ▁published ▁in ▁the ▁Pro ceed ings ▁of ▁the ▁National ▁Academy ▁of ▁Sciences ▁( PN AS ) ▁challeng ed ▁assumptions ▁about ▁the ▁caus al ▁nature ▁of ▁the ▁read iness ▁potential ▁itself ▁( and ▁the ▁" pre - mov ement ▁bu il dup " ▁of ▁neural ▁activity ▁in ▁general ), ▁casting ▁doubt ▁on ▁conclus ions ▁drawn ▁from ▁studies ▁such ▁as ▁Lib et ' s ▁and ▁Fried ' s . ▁ ▁A ▁study ▁that ▁compared ▁deliber ate ▁and ▁arbitrary ▁dec isions , ▁found ▁that ▁the ▁early ▁signs ▁of ▁decision ▁are ▁absent ▁for ▁the ▁deliber ate ▁ones . ▁ ▁It ▁has ▁been ▁shown ▁that ▁in ▁several ▁brain - related ▁conditions , ▁individuals ▁cannot ▁entirely ▁control ▁their ▁own ▁actions , ▁though ▁the ▁existence ▁of ▁such ▁conditions ▁does ▁not ▁directly ▁ref ute ▁the ▁existence ▁of ▁free ▁will . ▁Neu ros cient ific ▁studies ▁are ▁valuable ▁tools ▁in ▁developing ▁models ▁of ▁how ▁humans ▁experience ▁free ▁will . ▁ ▁For ▁example ,