4.003 Most sentences and questions that have been written about philosophical things are not false but rather nonsensical. So we cannot answer questions of this kind at all, but only ascertain their nonsensicality. Most questions and propositions of philosophers are based on our not understanding the logic of our language.
(They are of the same kind as the question whether the good is more or less identical than the beautiful.)
And it is not surprising that the deepest problems are really no problems at all.
This echoes the preface and reminds us to be on our guard against nonsense in the Tractatus itself. However, Wittgenstein only says that most philosophy is nonsense, not that it all is. So the possibility, as far as 4.003 alone goes, is distinctly open that the Tractatus is not nonsensical at all. But then why would he mention this idea here? Presumably, if the Tractatus is not nonsense, because what he is doing here is determining the nonsensicality of other philosophical ideas. Those of Russell and Frege, presumably, since it is primarily their ideas that are addressed in the Tractatus. These are implied to be no better than the worst kind of metaphysical claptrap.
Schopenhauer, in the midst of something of a rant about the state of German philosophy, which he regards as dishonest, pretentious, and empty, says in the Fourfold Root p. 169 that: “Moreover, “the Good, the True, and the Beautiful” are much in favour, especially with the sentimental and tender-hearted, as pretended Ideas, although they are simply three very wide and abstract concepts, in that they are drawn from innumerable things and relations, and are consequently very poor in substance, like a thousand other abstracta of a similar kind.”