第一章前几节，显然费雪告诉我们 real income=cost of living
但在第一章第13节有这么一段：“Or if the body mechanism, with its debits and credits, be omitted the total result is not his enjoyment income, subjectively considered, but the real income as above set forth. If we measure this, his real income, in money units, we find it equal to the total valuation of his cost of living less the total valuation of his own labor pain. ”
这段给出了real income=cost of living - labor pain
这一前一后的不同等式关系，是不是矛盾啊。还是我理解不到位？请赐教！