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That information is available in the current shot, but there's another source of information not available on the current shot,
以上這些信息是實時獲得的，但是另一個獲得信息的渠道，不是實時獲得的，
but only available by repeated experience in the game of tennis,
而是來自只有通過反復練習網球才得來的經驗，
and that's that the ball doesn't bounce with equal probability over the court during the match.
經驗告訴你，這個網球在比賽過程中，不會以均等的概率落在球場里。
If you're playing against a very good opponent,
如果你的對手水平很高，
they may distribute it in that green area, which is the prior distribution, making it hard for you to return.
可能會讓球的落點分布在圖上的綠色區域，也就是所謂的“先驗分布”，這些位置很難接到球。
Now both these sources of information carry important information.
那么現在，兩個信息源都包含重要的信息。
And what Bayes' rule says is that I should multiply the numbers on the red by the numbers on the green to get the numbers of the yellow, which have the ellipses, and that's my belief.
根據貝葉斯的理論，我們應該把紅色區域和綠色區域的數據相乘得到橢圓形的黃色區域，這就是我們的置信值。
So it's the optimal way of combining information.
并且這是整合信息的最佳方案。
I wouldn't tell you all this if it wasn't that a few years ago,
幾年前我們考察過，人們學習新動作新技巧的時候，
we showed this is exactly what people do when they learn new movement skills.
真的在遵循這樣的模式，所以我剛才才舉了這個例子。
And what it means is we really are Bayesian inference machines.
這說明我們實際上都是天生的貝葉斯推斷器。
As we go around, we learn about statistics of the world and lay that down,
在成長的過程中，我們不但學會了并記下了生活中的統計數據，
but we also learn about how noisy our own sensory apparatus is, and then combine those in a real Bayesian way.
也掌握了我們自己感官的雜音可能有多大，然后我們用貝葉斯法來整合處理這些數據。
Now a key part to the Bayesian is this part of the formula.
那么貝葉斯公式里很關鍵的是這一項--預測。
And what this part really says is I have to predict the probability of different sensory feedbacks given my beliefs.
這一項的意思是我們需要預測在原有置信值條件下，不同感官回饋的概率。
So that really means I have to make predictions of the future.
也就是說我們要對未來的可能做出預測。
And I want to convince you the brain does make predictions of the sensory feedback it's going to get.
我現在要說服各位相信一點，那就是大腦的確在對未來可能的感官回饋做出預測。
And moreover, it profoundly changes your perceptions by what you do.
并且你本身做了什么動作在很大程度上影響了你感知到的東西。
And to do that, I'll tell you about how the brain deals with sensory input.
為了說明這點，我來解釋我們的大腦如何處理感官輸入。
So you send a command out, you get sensory feedback back, and that transformation is governed by the physics of your body and your sensory apparatus.
我們先送出一個指令，然后得到一個感官回饋輸入回來，之間的轉換過程是由身體和感覺器官的物理過程完成的。
