2.033 The form is the possibility of the structure [or: Form is the possibility of structure].
If each state of affairs can be said to have a form, then its form will be the possibility of its structure, the logical space necessary for, or implied by, that structure. It can't have a different structure and still be that state of affairs. If form is instead something that belongs to the whole world (see 2.022) and not to individual states of affairs, then the parenthetical translation would be correct instead. Either way we seem to have more than we need here. Objects themselves are what we might call possibility spaces, so a state of affairs is a complex possibility space, not just a possibility point but a set of possibility coordinates. Now form is something like the possibility of this possibility, or the "space" in which this "space" exists. Perhaps the multiplication of pseudo-entities here is meant to help us see that we don't need any of them, that all this talk of objects and states of affairs and logical space is itself not only misleadingly metaphysical-sounding but also quite worthless. It is, we might suspect, a metaphor introduced as if to help us understand something, but one that turns out to be comprehensible only by reference to the things (color, hardness, etc.) that it was meant to help us understand. And realizing this perhaps also involves realizing that those things are not at all hard to understand after all. But this is speculation.
Ostrow (p. 25) argues that objects are not just form (i.e. possibility of structure), but also content, as is said of substance at 2.025. “It is constitutive of the object to occur in an atomic fact, but not only in this fact… [T]he object is this thing taken against the background of all the rest of its possibilities of combination with other things.” Otherwise the object would “be understood as dissolving simply into a possibility – as if we could understand the condition of the world apart from any consideration of how things actually stand.” (All quotes from p. 25.) On pp. 26-27 he says: “While we will no doubt be tempted to bring to bear notions like “particular,” “universal,” or “sense datum” to try to make sense of what he has in mind, Wittgenstein will not allow us to rely on any such categories as basic, as clarificatory. Indeed, it would appear to be the reverse: rather than seeking to understand objects in terms of some prior philosophical category, the Tractatus is suggesting that it is only through their possibilities of occurrence that those fundamental categories emerge. The object is, we might say, a primitive notion.”
Black (p. 67) notes that here we cannot ask “Is it possible that…?” in relation to the “possibility” that Wittgenstein refers to here. This makes interpretation problematic.