Wittgenstein's later reflections on language can be summed up in the statement (a paraphrase) "Of the things of which we cannot speak, we should remain silent." His reflections comprise a group of thought experiments which partially delimit language.

Among these reflections is the question "When can we say a child has learned to read?" What he is investigating is the question itself. This question's answer may be described as belonging to its grammar.

The question seems to imply access to a "private experience" of the child's, something which is 'demonstrably' impossible. Rather, at a certain point we simply say, "Oh, the child has learned to read."

Not only can't we ascertain the child's "private state," we can't speak speak of a its 'private state' at all: because the expression is inadequate to its purported meaning, its meaning can't be expressed; and because its meaning can't be expressed, the expression a meaningless term. While we can say the words, they will never mean anything.

Wittgenstein goes through a whole series of such experiments and casts doubt on every expression whose meaning attaches to some 'private state.'*

What he cannot doubt is pain. If someone cries out in pain, I have no doubt of their experience. It is this phenomenon, which is not formally meaning, that I am calling "empathy." I am suggesting that it may lie at the heart of ethics: because we empathize with one another, we recognize one another as members of an ethical community
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My observations on the documentary concern its strategy of manipulating empathy. How I feel about the ostensible subject of the documentary is completely irrelevant. I did not make this clear.

The question of a private state of a machine is virtually identical to that of the private state of a human being. The question whether they belong to an ethical community will be affirmed when we empathize with them. Whether or not we ever will empathize with them remains an open question. But our capacity to empathize with them is evidenced, among other places, in popular culture--including science fiction.

As a matter of logic, if machines become part of an ethical culture, just as there is no way to discuss the inner state of a child learning to read, there will be no way to differentiate between the ethical expressions of a human and those of a machine.

It was the illustration of this aspect of language I found fascinating in the documentary and which, I felt, made it relevant to the general topic of this board.

* use of scare quotes because, for reasons that are clear, the term is a tortured one.