▁when ▁referring ▁to ▁social ists , ▁while ▁contest ing ▁that ▁he ▁was ▁a ▁true ▁liberal . ▁ ▁Mac ph erson ' s ▁critic isms ▁of ▁Fried man ▁rest ▁on ▁three ▁claims : ▁( 1 ) ▁an ▁" error " ▁that ▁t arn ishes ▁Fried man ' s ▁attempt ▁to ▁demonstrate ▁that ▁capital ism ▁organ izes ▁the ▁economic ▁activities ▁of ▁society ▁without ▁co erc ion ; ▁( 2 ) ▁the ▁" ina de qu acy " ▁of ▁his ▁assertion ▁that ▁capital ism ▁is ▁a ▁necessary ▁component ▁of ▁freedom , ▁and ▁that ▁social ism ▁is ▁incons istent ▁with ▁freedom ; ▁and ▁( 3 ) ▁the ▁" f alla cy " ▁of ▁his ▁evidence ▁that ▁capital ism ▁is ▁an ▁eth ically ▁sound ▁principle ▁of ▁distribution . ▁ ▁Mac ph erson ▁cont ends ▁that ▁the ▁co erc ion ▁in ▁capital ism ▁is ▁that ▁one ▁cannot ▁choose ▁not ▁to ▁be ▁subject ed ▁to ▁capital ist ▁economic ▁relations ▁in ▁a ▁capital ist ▁society . ▁One ▁can , ▁of ▁course , ▁choose ▁to ▁change ▁jobs , ▁but ▁one ▁cannot ▁choose ▁not ▁to ▁work . ▁ ▁For ▁the ▁exchange ▁to ▁be ▁truly ▁volunt ary ▁" the ▁prov iso ▁that ▁is ▁needed ▁is ▁whether ▁to ▁enter ▁into ▁any ▁exchange ▁at ▁all ." ▁▁ ▁The ▁workers ▁need ▁money ▁but ▁cannot ▁bar ter ; ▁therefore , ▁they ▁are ▁co er ced ▁into ▁the ▁mon et ary ▁system . ▁ ▁Furthermore , ▁the ▁volunt ary ▁nature ▁of ▁the ▁exchange ▁is ▁only ▁evident ▁in ▁cases ▁of ▁perfect ▁competition ▁where ▁each ▁product ▁is ▁the ▁same ▁and ▁there