▁an ▁infer red ▁magnitude ). ▁Product - values ▁manifest ▁themselves ▁and ▁can ▁only ▁be ▁expressed ▁as ▁trad ing ▁r ati os , ▁( ide al ) ▁prices , ▁or ▁quantities ▁of ▁labour - time , ▁and ▁therefore ▁the ▁academic ▁" trans formation ▁controvers y " ▁is ▁according ▁to ▁many ▁modern ▁Marx ist ▁the or ists ▁mis gu ided ; ▁it ▁rest s ▁simply ▁on ▁a ▁false ▁interpretation ▁of ▁the ▁relationship ▁between ▁the ▁value - form ▁of ▁comm od ities ▁and ▁the ▁price - form . ▁What ▁Marx ▁really ▁meant ▁by ▁the ▁" trans formation " ▁was ▁that ▁the ▁direct ▁reg ulation ▁of ▁the ▁exchange - value ▁of ▁comm od ities ▁according ▁to ▁their ▁labour - value ▁is , ▁in ▁a ▁capital ist ▁mode ▁of ▁production , ▁transformed ▁into ▁the ▁reg ulation ▁of ▁the ▁exchange ▁of ▁comm od ities ▁by ▁their ▁production ▁prices — reflect ing ▁the ▁fact , ▁that ▁the ▁supply ▁of ▁comm od ities ▁in ▁capital ist ▁society ▁has ▁become ▁conditional ▁on ▁the ▁accum ulation ▁of ▁capital , ▁and ▁therefore ▁on ▁profit ▁marg ins ▁(" no ▁profit , ▁no ▁sale "). ▁As ▁soon ▁as ▁we ▁admit ▁that ▁product - pr ices ▁may ▁fl uct uate ▁above ▁or ▁below ▁the ▁soci ally ▁average ▁product - values ▁for ▁all ▁kinds ▁of ▁reasons — a ▁central ▁determin ant ▁of ▁market ▁dynamics — the ▁quant itative ▁relationship ▁between ▁product - values ▁and ▁product - pr ices ▁is ▁at ▁best ▁probabil istic , ▁not ▁a ▁fixed ▁function ▁of ▁some ▁type . ▁The ▁structure ▁of ▁Marx ' s