47. But what are the simple constituent parts of which reality is composed?—What
are the simple constituent parts of a chair?—The bits of wood of which it is
made? Or the molecules, or the atoms?—"Simple" means: not composite. And here
the point is: in what sense 'composite'? It makes no sense at all to speak
absolutely of the 'simple parts of a chair'
Again: Does my visual image of this tree, of this chair, consist of parts? And what are its simple component parts? Multi-colouredness is one kind of complexity; another is, for example, that of a broken outline composed of straight bits. And a curve can be said to be composed of an ascending and a descending segment.
If I tell someone without any further explanation: "What I see before me now is composite", he will have the right to ask: "What do you mean by 'composite'? For there are all sorts of things that that can mean!"—The question "Is what you see composite?" makes good sense if it is already established what kind of complexity—that is, which particular use of the word—is in question. If it had been laid down that the visual image of a tree was to be called "composite" if one saw not just a single trunk, but also branches, then the question "Is the visual image of this tree simple or composite?", and the question "What are its simple component parts?", would have a clear sense—a clear use. And of course the answer to the second question is not "The branches" (that would be an answer to the grammatical question: "What are here called 'simple component parts'?") but rather a description of the individual branches.
But isn't a chessboard, for instance, obviously, and absolutely, composite?—You are probably thinking of the composition out of thirty-two white and thirty-two black squares. But could we not also say, for instance, that it was composed of the colours black and white and the schema of squares? And if there are quite different ways of looking at it, do you still want to say that the chessboard is absolutely 'composite'?—Asking "Is this object composite?" outside a particular language-game is like what a boy once did, who had to say whether the verbs in certain sentences were in the active or passive voice, and who racked his brains over the question whether the verb "to sleep" meant something active or passive.
We use the word "composite" (and therefore the word "simple") in an enormous number of different and differently related ways. (Is the colour of a square on a chessboard simple, or does it consist of pure white and pure yellow? And is white simple, or does it consist of the colours of the rainbow?—Is this length of 2 cm. simple, or does it consist of two parts, each 1 cm. long? But why not of one bit 3 cm. long, and one bit 1 cm. long measured in the opposite direction?)
To the philosophical question: "Is the visual image of this tree composite, and what are its component parts?" the correct answer is: "That depends on what you understand by 'composite'." (And that is of course not an answer but a rejection of the question.)