The same way anything else can be; “ownership” is the legal right to exclude others from some set of actions with regard to something. Whether the something is tangible or not is basically immaterial, except as tongue set of possible actions that might be governed by ownership.
> Intangible things aren't scarce.
So? Property is about structuring incentives to create value, it is not intrinsically tied to scarcity (except that property—the legal exclusive privilege—is inherently scarce even if it's subject is not.)