Superheavy elements [SHEs] are strange: they do not exist in nature, and their half-lives are so brief that they possess no ground-state electronic structure, and are therefore unable to exhibit any chemical properties. Nevertheless, elements like oganesson have been uncontroversially accepted into the periodic table, with their discoveries celebrated - if carefully officiated - by the International Union of Pure and Applied Chemistry [IUPAC]. This recognition has been taken to put pressure on the basic concept of a chemical element: how can an element exist, if it has no chemistry?

This paper asks another question: how can an element be discovered, if it doesn't exist? Chemical elements are defined by IUPAC as atomic species with discrete nuclear charges. But, by the time SHEs have settled into atoms with stable electronic structures, their nuclei have already decayed into other atomic species; no ground-state atom of oganesson has ever existed. What do we mean, then, when we say that oganesson has been discovered?

Through a discussion of IUPAC's initial codification of the contemporary elemental discovery criterion, I argue that the recognition of SHEs required a redefinition of what it means to be a 'chemical element' in the first place. The discovery of SHEs could only occur on the basis of a classificatory choice on the part of the chemical community. This puts pressure on common understandings of scientific discovery more generally, and suggests a more fundamental role for community consensus than recent historical and philosophical treatments of chemical discovery have acknowledged.

Chemistry is dedicated to the exploration of the nature of substances. Almost daily, new
chemical entities, some of them substances, are found. The verification of the existence of
these novelties is customarily described as an analytical task. One – more systematical –
aspect of the present paper is to show that chemical identification generally entails synthetical
steps. Another – more historical – aspect is to show that many chemical discoveries happened
by chance rather than by plan or on purpose.
Three historical cases will be discussed: the introduction of helium as a chemical element
around 1895, Moses Gomberg’s making of the “first” stable organic radical around 1900, and
the “discovery” of the glass electrode around 1906. In each of these cases, chance played a
significant role, and, additionally, it took a long time to understand and establish the
respective aspects as stable knowledge.
Because of the complex relational character of stuff changes, chemistry is, as already Kant
rightly pointed out, an unmathematical systematic art or experimental doctrine: The margin
for predictions is restricted, and the laboratory actions of the proponents of that systematic art
are decisive.

The papers in these three sessions have addressed the nature of discovery in chemistry and provided a wealth of case studies. What is striking in many of the papers is how much historical, philosophical and scientific understanding we can gain from paying close attention to the uncertainties and disputes concerning what exactly it was that had been discovered, and what was required for reaching agreement. It is also notable that a wide variety of types of things that have been discovered, which is instructive for thinking in a fresh way about the nature of scientific knowledge.