7. Disorder increases as time passes.
隨著時(shí)間的流逝，宇宙的無(wú)序程度會(huì)上升。

At the heart of every difference between the past and future — memory, aging, causality, free will — is the fact that the universe is evolving from order to disorder. Entropy is increasing, as we physicists say. There are more ways to be disorderly (high entropy) than orderly (low entropy), so the increase of entropy seems natural. But to explain the lower entropy of past times we need to go all the way back to the Big Bang. We still haven't answered the hard questions: why was entropy low near the Big Bang, and how does increasing entropy account for memory and causality and all the rest?
在過(guò)去與未來(lái)的所有差別——記憶、衰老、因果、自由意志——背后，隱藏著一個(gè)核心事實(shí)，那就是宇宙是從有序逐漸走向無(wú)序的。或者如物理學(xué)家所說(shuō)：“熵（動(dòng)力學(xué)方面不能做功的能量總數(shù)）在不斷增加。”達(dá)到無(wú)序狀態(tài)（高熵）比達(dá)到有序狀態(tài)（低熵）的途徑要多，因此熵的增加看起來(lái)再正常不過(guò)。但要解釋宇宙曾有過(guò)的低熵狀態(tài)，就必須回溯至最初的宇宙大爆炸。我們?nèi)匀徊荒芑卮鹑缦聠?wèn)題：為何在大爆炸之時(shí)熵如此低，以及熵增如何導(dǎo)致了記憶、因果以及其他一切。