Carys Craig is an Associate Professor at Osgoode Hall Law School.

In copyright law, the term "public domain" is commonly used to describe the sphere in which contents are free from copyright protection. The typical example is that of a work whose protection has expired, or one that fails to meet the minimum requirements.  Such works belong in what Pamela Samuelson has famously called the "core" of the public domain. Also within this "core", however, are those aspects of copyrighted works that copyright does not protect. Ideas, concepts, theories, systems, methods, facts, information, and unoriginal elements all belong in the public domain, notwithstanding that their expression, description, illustration, compilation, selection or arrangement may be protected.

Even this overtly legalistic definition suggests the inevitable indeterminacy of the public domain. The doctrinal line between public and private will shift over time and with circumstances, not to mention by jurisdiction. The boundaries are even more contentious if we resist the idea that the public domain contains only works or aspects of works devoid of protection. A recurring controversy, for example, is whether particular uses of protected works that fall within exemptions or limitations can be conceptualized as within the public domain. It may seem strange to describe a statutorily permitted use as somehow rendering a protected work public domain in a specific instance. But if we take uses - as opposed to works or parts thereof - as our unit of analysis, we might say that public domain information is (as Yochai Benkler defines it) information "whose use, absent special reasons to think otherwise, is permissible to anyone."

Indeed, if the public domain embraces any use for which permission is not required, it will include use of an insubstantial part of a work, as well as statutorily permitted uses such as fair dealing and exceptions for, e.g., educational institutions, libraries, archives, and museums. It would appear that the Supreme Court of Canada endorsed this use-based understanding of the public domain when Justice Binnie wrote, in Théberge, that the exceptions to copyright infringement enumerated in the Copyright Act "seek to protect the public domain." While Teresa Scassa has wondered whether this was an "overstatement by the Court of the concept of the public domain," I would suggest that we embrace it as a necessary and timely step towards a positive theory of the Canadian public domain.

The use-based approach departs from traditional conceptions of the public domain as a separate realm, demanding as it does a dynamic and contextual definition. This departure is made easier if we remind ourselves that the notion of the public domain as a static and distinct preserve was only ever a metaphor, and not a particularly apt one at that. If the public domain (like so much else in IP law) is ultimately metaphorical, we should be asking ourselves not "what is the public domain?", but "what do we need it to be?"

When defined only in the negative (IP-free), the public domain is a fragile thing: situated outside of copyright, it lacks normative significance, and its contents are vulnerable to the rationales of propertization. The dynamic public domain is a far more robust creature: it is the realm of public entitlement and users' rights, occupying a central role in the objectives of copyright policy, and providing affirmative protection against the encroachment of IP rights.

In 1981, David Lange called for an affirmative theory of the public domain with the political capacity to counter the excesses of propertization and stem the tide of IP expansion. In 2009, as copyright law struggles to adjust to the new realities of our networked society, Canadians may finally have to heed this call. The Supreme Court has articulated a vision of a robust public domain that can "incorporate and embellish creative innovation in the long-term interest of society as a whole" (Théberge) and "help foster future creative innovation" (CCH). This sets the stage for an affirmative account of the Canadian public domain as a vibrant cultural space for exchange and transformation, inspiration and innovation-a public domain with a positive dimension and political power. With copyright reform looming, we should be ready to harness this power in defence of users' rights, and in response to demands for ever-increasing protection in the digital age.

Carys Craig's essay "The Canadian Public Domain: What, Where and to What End?" will appear in Rosemary Coombe & Darren Werschler-Henry (eds), Dynamic Fair Dealing: Creating Canadian Culture Online (forthcoming).