2007年9月20日

「價值」是什麼?(四)

當利率不變時,我們的銀行存款利息的多寡的確是由本金大小所決定的,但這是由存款人的角度來看的。現在讓我們換個角度。假如某甲有一個十年定存的銀行帳戶,不可中途解約,現在他想把這個還有八年才到期的十年定存帳戶轉讓求現,你願意出多少錢呢?你會出等於本金的價錢嗎?或者你會開始思考這個銀行帳戶對你而言到底值多少錢呢?這也就是Irvin Fisher想要弄清楚的觀念。(類似例子可參看如何選擇折現率(三)。)

當然,Irving Fisher知道很多人對他前面說的觀點會感到不解,他接著提出了解釋:

This statement may at first seem puzzling, for we usually think of causes and effects as running forward not backward in time. It would seem then that income must be derived from capital; and, in a sense, this is true. Income is derived from capital goods. But the value of the income is not derived from the value of the capital goods. On the contrary, the value of the capital is derived from the value of the income. Valuation is a human process in which foresight enters. Coming events cast their shadows before. Our valuations are always anticipations.

譯文:
這種說法乍聽之下可能讓人不解,因為我們習慣認為因果關係在時間上是因在先果在後,而非顛倒過來。所以看來收入應該是由資本(財)衍生出來才對,這在某種意義上是對的。收入是由資本財所衍生的,但收入的價值並非由資本財的價值所衍生的。正好相反地,資本財的價值是由其所產生的收入的價值所決定。評價是一種人們所進行的程序,其中包含對未來的臆測。未來事件在其未發生之前就已投射下它自己的身影。我們做價值評估時,其實是對未來的一種期望

These relations are shown in the following scheme in which the arrows represent the order of sequence—(1) from capital goods to their future services, that is, income; (2) from these services to their value; and (3) from their value back to capital value:


譯文:
前述的關係可用上面的圖來表示。箭頭代表先後次序:(1)由資本財到它未來所生產的服務,亦即未來的收入;(2)由那些未來的收入到它們的價值;(3)再由那些未來收入的價值到資本財的現在價值。

Not until we know how much income an item of capital will probably bring us can we set any valuation on that capital at all. It is true that the wheat crop depends on the land which yields it. But the value of the crop does not depend on the value of the land. On the contrary, the value of the land depends on the expected value of its crops.

譯文:
如果我們不知道一件資產會帶給我們多少的收入,我們就完全無從評估其價值。是沒錯,稻米要靠土地來生產,但稻米的價值並不由土地的價值多少來決定。相反地,該塊土地的價值要看它未來所能生產的稻米價值而定。


至此,我想讀者應該弄清楚Irving Fisher的意思了。我們習於順向思考事務,對表象視為理所當然,很少做進一步的思考,Irving Fisher的不同思維方式的確令人為之擊節讚賞,值得我們反覆推敲、仔細玩味。

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