Verifiability and the elimination of metaphysics: are metaphysical pseudo-propositions like Heidegger's 'Das Nichts nichtet' meaningless because they violate the logical syntax of language, and does the 1936 Testability and Meaning refinement deepen or recant the 1932 attack?

Rudolf Carnap, answered from the texts and cited to the page.

The position in brief

Metaphysical pseudo-propositions like Heidegger's "Das Nichts nichtet" (the Nothing noths) are not false but meaningless. They violate the logical syntax of language by treating the word "Nothing" as a substantive that can be the subject of a predicate — grammar permits the construction but logical analysis shows the construction asserts nothing whatsoever.¹

Metaphysical pseudo-propositions are like lyrical poetry, like music, like laughter: they express an emotional or volitional attitude toward life, but they give the illusion of knowledge where there is none.² The 1932 Elimination essay gives the position in its sharpest form. The 1936-37 Testability and Meaning refinement softens the strict verifiability principle into the more nuanced confirmability- plus-translatability criterion to accommodate the observation that scientific theories cannot be conclusively verified but can be progressively confirmed — a deepening of the position, not a recantation.

The 1929 Davos disputation between Cassirer and Heidegger was the formative philosophical-political moment at which the analytic and continental traditions diverged.³⁴

Sources

This neutral attitude with respect to different language forms led me later to adopt the principle of tolerance in Logical Syntax. Even in the pre-Vienna period, most of the controversies in traditional metaphysics appeared to me sterile and useless.
Intellectual Autobiography, pp. 55–56
Examples of this are cries like "Oh, Oh" or, on a higher level, lyrical verses. The aim of a lyrical poem in which occur the words ""sunshine" and "clouds", is not to inform us of certain meteorological facts, but to express certain feelings of the poet and to excite similar feelings in us. A lyrical poem has no assertional sense, no theoretical sense, it does not contain knowledge.
Philosophy and Logical Syntax Ch1 - The Rejection of Metaphysics, p. 3
In saying that the so-called statements of metaphysics are meaningless, we intend this word in its strictest sense. In a loose sense of the word a statement or a question is at times called meaningless if it is entirely sterile to assert or ask it. We might say this for in- S stance about the question "'what is the average weight of those inhabi-: tants of Vienna whose telephone number ends with '3'?" or about.
The Elimination of Metaphysics Through Logical Analysis of Language, pp. 4–5
Or is it the other way around? Does Negation and the Not exist only because the Nothing exists?... We assert: the Nothing is prior to the Not and the Negation.... Where do we seek the Nothing? How do we find the Nothing.... We know the Nothing.... Anxiety reveals the Nothing.... That for which and because of which we were anxious, was 'really'—nothing. Indeed: the Nothing itsel{—as such—was present...
The Elimination of Metaphysics Through Logical Analysis of Language, pp. 12–13

Where the argument is made

"The Elimination of Metaphysics Through Logical Analysis of Language" (1932, in Ayer ed. Logical Positivism 1959 — the canonical attack on Heidegger's Das Nichts nichtet)
"Testability and Meaning" (1936) + "Testability and Meaning — Continued" (1937, Philosophy of Science essays) refining the strict verifiability principle into the confirmability-plus-translatability criterion
the chapter "The Rejection of Metaphysics" in Philosophy and Logical Syntax (1935, the popular statement of the syntactical-period position)
the relevant sections of Logical Syntax of Language (1934) on language-relativity and pseudo-propositions
the discussion in Philosophical Foundations of Physics (1966) on the verifiability principle in late form

How the argument was received

settled-with-1936-refinement-as-deepening