Editor's Introduction

the papers in this special issue of social research were first presented on April 4 and 5, 2019, at the thirty-eighth Social Research conference at the New School, "Unknowability: How Do We Know What Cannot Be Known?" From the earliest moments of humanity's search for answers and explanations, we have grappled with the unknowable—that which we are unable, or not permitted, to know. In this issue, our authors explore how we decide that something is unknowable rather than merely not yet known, and what criteria we use in determining that some knowledge is beyond our reach, and whether these criteria differ across fields and disciplines.

What does the history of the unknowable look like? What are the now-answered questions that we once thought unanswerable? Are there enduring unknowables? Are there modes of understanding that are different from the ones used by scientists, and what is the status of knowledge gained in these alternate ways? These and other questions were the subject of our conference and are addressed in this issue.

The question of what we cannot know is not only important in its own right but has also taken on additional importance in light of the rise of misinformation and "alternative facts." A better understanding of whether or not something can possibly be known has the capacity to shape inquiry, scholarly research, and public education. Furthermore, identifying what kinds of questions are unanswerable is of great intellectual and perhaps even political significance—to wit, Donald Rumsfeld's now-famous statement that "there are known knowns … there are known unknowns … and there are also unknown unknowns," to which Fintan O'Toole added "unknown knowns."

The "Unknowability" conference afforded a rare opportunity for scholars from different fields to engage with these questions during this seemingly post-truth moment in which we all are living. We hope the conference papers collected in this special issue will encourage our readers to explore these questions themselves.

We are grateful to the National Science Foundation for providing the funding that made the "Unknowability" conference possible.