In previous installments of my series onFreud as a philosopherI described how during Freud’s lifetime the sciences of the mind were guided by assumptions about the nature of the mind and its relation to the body that he came to reject. These included the notion thatmind and body are categorically distinct (“dualism”), thatall mental processes are conscious, and that the best way to explore the mind is through introspection.

弗洛伊德拒绝了所有这些主张。相反，他认为精神状态就是大脑状态(“唯物主义”)，心理过程是无意识的，我们只能间接接触到自己的思想，内省并不是探索思想的充分工具。这种哲学上的转变对他创造精神分析理论和实践至关重要。在这篇文章中，我想通过阐述他的一个关键论点来解释弗洛伊德是如何得出这一观点的。He didn’t give the argument a name, so I’ve taken the liberty of calling it thecontinuity argument.

The continuity argument was inspired by several sources. One was John Stuart Mill’s bookExamination of the Philosophy of Sir William Hamiltonwhich Freud purchased in 1889. In the book, Mill cites a remark by Hamilton that:

It sometimes happens that we find one thought rising immediately after another in consciousness, but whose consecution we can reduce to no law of association. Now in these cases we can generally discover… that these two thoughts… are each associated with certain other thoughts, so that the whole consecution would have regular, had these intermediate thoughts come into consciousness….

Other sources included the physiologist Ewald Hering, the philosopher Theodor Lipps, who influenced him greatly, and possibly even David Hume. But Freud didn’t simply appropriate the thoughts of others. He used them to develop a powerful and original argument that goes well beyond what his predecessors had said.

The continuity argument takes off from the observation that our conscious mental life isboth gappy and continuous across the gaps. Here’s how Freud expressed this idea in his 1915 paper “The Unconscious” (one of the most philosophical of his works).

The data of consciousness have a very large number of gaps in them; both in healthy and in sick people psychical acts often occur which can be explained only by presupposing other [psychical] acts, of which, nevertheless, consciousness affords no evidence…. [O]ur most personal daily experience acquaints us with ideas that come into our head, we do not know from where, and with intellectual conclusions arrived at we do not know how.

弗洛伊德是对的，这很容易从个人经验中确认。这是一个例子。刚才，我在写论文的间隙打了个盹。我躺在客厅的沙发上，很快就进入了无梦的沉睡。大约20分钟后，我醒来，脑海中出现了一些关于如何展开这篇文章的新想法。所以，在我的有意识的精神生活中有一个空隙(小睡)，并且在这个空隙中有连续性(我醒来后对如何继续写文章有了一些新的想法)。

But hold on, there seems to be a contradiction here! How can mental sequences be simultaneously continuous and gappy? Freud shows us how to resolve this seeming contradiction by letting go of some incorrect assumptions about the nature of the human mind.

争论是这样进行的。假设，就像弗洛伊德同时代的许多人所做的那样，所有的心理过程都是有意识的。由此可以得出，如果我们的有意识的精神生活中存在间隙，那么在这些间隙中没有任何精神活动发生。所以，从这个角度来看，当我打盹的时候，我的脑子里什么都没有发生。但是，如果在间隙之后出现的想法和在间隙之前出现的想法是连续的——换句话说，如果我们的有意识的想法是连续的，那么一定有什么事情在进行，以确保这种连续性。一个下意识的反应可能是:“嗯，有无意识的大脑活动在进行，所以我们难道不能说，在间隙期间发生的事情根本不是真正的精神活动，只是无意识的物理神经元放电吗?”

Well wecouldsay that, but it wouldn’t really help, because whatever’s taking place during these gaps in consciousness has got to be able to preservementalcontinuity. It’s got to be able to explain how it was possible for me to make progress on an essay while I’m asleep. To accomplish that, it looks like whatever was going on in my brain while I was napping couldn’t have been mindless. If we grant—as Freud thought we should—that my brain was churning away unconsciously during the nap, we should also conclude that these neurophysiological churnings were mental in nature.

Freud’s continuity argument leaves us with three very striking conclusions that contradict the pre-Freudian assumptions that I spelled out in the first paragraph of this essay. One is that mental processes can be entirely unconscious, and another is that mental processes are the very same thing as brain processes. And this implies that, as Freud put it in 1895, introspection gives us “neither complete nor trustworthy knowledge of the neuronal processes” which are “to be regarded to their whole extent as unconscious and are to be inferred like other natural things.”

My original plan was to end my Freud series here. But then I thought to myself “David, how can you write a series about Freud without discussing his views about sex?” So, next monthI’ll wrap up the series with an essay on Freud’s philosophy of sex.