The science we are used to in our everyday life is observational, based on inferences made by sensory experiences enhanced by technological tools. Black holes, however, cannot be seen: scientists have observed their effects on neighbouring bodies, yet they are, by definition, invisible. They are part of a different, more speculative science, one that allows astronomers to imagine what black holes may be and what may be ‘in’ them. General relativity tells us that ‘falling’ into a black hole would lead an object to a singularity, a point of infinitely strong gravity which is simply the end. General relativity cannot conceptualise what is beyond, in, or at the singularity. This is where ‘physics just stops’, although quantum physicists are trying to open up black holes by allowing a reality to exist beyond this end-point. Speculations about the limits of reality are poetic, albeit also somewhat unsettling: physicists such as Nikodem Popławski of the University of New Haven have proposed that every black hole may contain a universe and that, therefore, our own existence may be similarly contained within one.
Black holes have stimulated fantasies of space travel in science fiction, across the universe and across universes alike. Although a matter of films, this is not without scientific foundation. The reality of black holes that we have now is created within mathematics, a ‘language’ that, restrictive as it may seem to many, allows for imaginative speculation. ‘The equations of general relativity […] are symmetric in time’; therefore, it is mathematically possible for reversed black holes to exist – white holes, regions within which nothing can fall. A black hole and a white hole can be united by an Einstein-Rosen bridge, or what we came to call a wormhole, creating a hole through spacetime. Whether they are bridges or tunnels, wormholes have captured our imagination as uniting distant places, or even different universes.
There is no observation of black holes yet possible, only (rigorous and mathematical) speculation. Science cannot obtain direct knowledge about black holes, a situation that has attracted the attention of philosopher Graham Harman. Harman’s ‘Object Oriented Ontology’ has the purpose of saving objects from what he identifies as European philosophy’s assault on them, either undermining objects by trying to always reach something ‘deeper’, or reducing objects only to their qualities. Harman aims to do this, however, without claiming knowledge or access to the thing-in-itself. He uses Heideggerian vocabulary to claim that objects are ‘withdrawn’ from us and from each other. He is part, therefore, of a trend of ‘Speculative Realism’, and has drawn a parallel between his speculation on objects and scientific speculation on black holes. In his book Prince of Networks (pp. 184-5), Harman writes that, as black holes are not only their visible effects on the surrounding matter, so are objects something beyond just their ‘sensuous qualities’. The analogy works further: as black holes exert an immense fascination on both scientists and laymen, so should philosophers not shy away from studying objects just because they are not directly accessible to us. We are fascinated with black holes, but we find (or do not find) similar mysteries all around us: objects. They deserve, Harman argues, as much attention and enthusiasm as black holes.
Harman’s purpose in discussing black holes is also a more general one: he tries to show that science is not completely different from arts. Black holes, as a subject of scientific enquiry, do not lend themselves to direct knowledge, but to oblique cognition, as that which can be obtained through non-scientific explorations of objects. Harman pushes philosophers to begin (again) to speculate about the world. He argues that, if scientists legitimately speculate about things such as black holes, philosophers can do so as well. If science can create tentative knowledge about objects that we cannot access, then arts and philosophy can reclaim their own speculative understanding of what has come to be seen the domain of scientists: the Great Outdoors. Black holes straddle the line of disciplines and break the boundaries between science and arts, and between different (maybe even opposing) epistemologies. They may not be holes as those we encounter in everyday objects, but black holes can open up immense spaces within our cognition.
Andrei Belibou (Department of Politics and International Studies, University of Warwick)