Notes on: Barad, K. (2010) Quantum Entanglements and Hauntological Relations of Inheritance: Dis/continuities, SpaceTime Enfoldings, and Justice to Come. Derrida Today 3 (2) 240--68 DOI: 10.3366/E1754850010000813

Dave Harris

Continuity is a major idea and it is a good experiment to think what would happen if we disrupted it. We have to develop a participation 'more akin to how electrons experience the world than any journey narrated through rhetorical forms that presume actors move along trajectories across a stage of space-time'. (240) Analogies between macro and micro are 'flat-footed' and already presume a spatial scale. We need to think about dis/continuity, dis/orientation and dis/jointedness — quantum dis/continuity, with no overarching temporality or continuity, but a series of different temporalities and reconfigurations, threaded through one another. This will help us feel différance, interactivity and 'agential separability—differentiatings that cut together/apart' (241).That will be hauntology

Derrida is quoted about ghosts as others and how we must do justice to them [Spectres I think]. This leads to a reconstruction of 'Elsinore by way of Copenhagen', a reconstruction of when Heisenberg met Böhr in 1941, with references to Frayn's play. We're going to diffract events through 1927 and then 1945. [Frayn's play is quoted, leading up to the question of whether physicists have the moral right to work on applications of atomic energy]

Why did Heisenberg go to Copenhagen? Was he trying to find out what Böhr knew about the bomb project, or to warn him that he was involved in the German project but would try to delay it? Was the conversation to be about physics or ethics or both? They are 'inextricably fused'(242) for Barad.

Another act and scene [hers?] — Events diffracted through the play and through the moment in 1927 when quantum physics was first developed and Heisenberg and Böhr disagreed. Followed by various thought experiments including quantum erasers and entanglements, diffracted through her own book. Here, 'diffraction as synecdoche of entangled phenomenon [sic]… Reading texts interactively through one another, enacting new patterns of engagement, attending to how exclusions matter' (243). Then diffracted through Derrida on spectres, itself diffracted through Hamlet and the 1848 manifesto. Newton in 1687 is diffracted through '2060 '[Newton's prediction for the end of time, 'derived… from biblical prophesizing, calculation, anti-speculative speculating']. Or Böhr's Nobel prize-winning explanation in 1912 diffracted through Schrödinger and the cat in 1935, and then the dropping of the atomic bombs in 1945 — [to give you an example of the style: '/diffracted through 1945 [dropping of atomic bombs on Hiroshima and Nagasaki: cities populated with the living dead; a ghostly/ghastly scene; hauntings]/…/Wartime/science time/space-time/imaginary time/mythic time/storytime/inherited time/].Time is out of joint

This is a beginning already threaded through with anticipation of where it's going and 'of a past that is yet to come'. We are talking of 'multiply heterogeneous iterations' rather than linear unfolding, threading through (244), a topology. Disjointedness itself is under question [the relation between joining and disjoining which she expresses as dis/joining]. Intra-action is a single event, cutting together/and the part 'not separate consecutive activities'. The relationship between continuity and discontinuity is not just a simple negative opposition but rather 'of im/possibilities'.

She tries to write this paper so as to disrupt historical narrative forms that underpin scientific progress, discoveries that lead out of ignorance and uncertainty. This instead is 'an imaginative journey that is akin to how electrons experience the world', disorienting, entangling, dis/continuous, in a way which goes beyond normal definitions [or as she puts it 'which is neither fully discontinuous with continuity or even fully continuous with discontinuity']. There is no overarching time or place. Readers are not assumed to be in the here and now. Individual scenes are 'not wholly separate, nor parts of a whole' and there is no smooth topology. Instead 'each scene diffracts various temporalities, iteratively differentiating and entangling… Across the field of spacetimmattering'. Scenes are constantly reconfigured dispersed and threaded. 'The reader should feel free to jump for any scene to another... and still have a sense of connectivity'(245).  she hopes there will be 'a felt sense of différance, of interactivity, of agential separability – differentiating is that cut together/apart' [could be very pseudy and risks adverse reader reactions — like mine]

A new scene comparing Derrida on the exit and re-entry of the ghost, with Einstein saying that electrons cannot choose of their own free will, and if they did, he would rather be a cobbler.

Particles have 'paroxysms — spasmodic bouts of e-motion or activity'. They seem to resist notions in classical physics of mechanical forces and supply instead 'strange agency' it is 'passion–at–a–distance' [referenced to a certain D Mermin]. Böhr's first model in 1912 was based on the planetary model of orbiting electrons, but it has problems in retaining its energy and avoiding spiralling into the nucleus. Planck in 1900 had quantised energy into discrete packets, and Einstein in 1905 proposed that light is quantised in photons, and it is this that gets him the Nobel prize.

Böhr replaces his original idea with one where the electrons do not orbit the nucleus, but rather reside in particular energy levels, only emitting photons when they jump from one level to another, for example from a higher to a lower energy state. This preserves the electron's energy and the stability of the atom. Each atom displays a discrete pattern in its spectrum [rather than a continuous emission of light uncomfortably predicted by the ball model]. Predictions match experimental results for hydrogen winning Böhr the Nobel prize, and showing that atoms have parts.

However 'spectres abound' — what is the nature of these jumps? A quantum is the smallest possible unit [she quotes Wiktionary here!], implying a discrete quality to nature. However electrons jump in a discontinuous fashion — 'initially at one energy level and then it is  at another without having been anywhere in between' (246). This is 'particularly queer' and challenges easy dichotomies between dis and continuity, and dichotomy for that matter. Quantum queerness is further developed, and here she means not 'simply strange' but the very 'undoing of identity' a crucial dis/continuity.

Further work displays more of the 'spectral quality of this process' (247). Rutherford thought that electrons would continually emit light across their range of energy values, but Böhr suggest that electrons only occupy a discrete set of energy levels and light is emitted in a packet, 'all at once as a photon'. This must happen at some moment in time, but investigation shows that 'the situation is quite spectacular'. In a given energy state, there is no energy change and so a photon cannot be emitted, except as the result of the jump itself — but the electron is never anywhere in between the energy states. Indeed, atoms emitting photons of a given colour imply that the electron is going to 'already wind up where it was going… before it left' [apparently, the conservation of energy means that it can't produce several variants]. This is 'a queer causality indeed!'. For Barad, this paradox in causality  'derives from the very existence of a quantum discontinuity in the cutting together/apart that is the nature of all interactions'.

This is a new kind of dis/continuity, not just a displacement in space through time. The rupture itself involved in a jump 'helps constitute the heres and nows' — here and now there and then 'have become unmoored' (248) — if we cannot decide where and when quantum jumps happen, we cannot deploy simple notions of causes and effects.

It is difficult to see how such a strange unstable process leads to stable existence. We can certainly see the world as 'an open-ended becoming'[but we have still not explained stability]. It is even more complex because there is no stable notion of change either — it 'changes with each intra-action', it has 'a dynamism that operates at an entirely different level of existence' from the usual conception of matter in space and time. This implies that we have to rethink space and time as well, so that 'what comes to be and is immediately reconfigured entails an iterative intra-action becoming of spacetimemattering' . We have a radical notion of undoing, a rupture, a disruption 'a cut raised to a higher power forever repeating', a irresolvable internal contradiction, logical disjunction or impasse, seen in quantum tunnelling which rejects simple notions of closure and wholes and produces 'an impossible possibility'.

A new scene discussing Newton and the diffraction offered by Laplace and his thought experiments which extend to every particle and make time calculable, entire. These conceptions have affected our very understanding of change. Continuity gave Newton the calculus and thus a deterministic world, 'at Man's feet' (249), clockwork nature. Thus a radical difference between continuity and discontinuity 'is the gateway to Man's stewardship' and produces a 'God's eye view of the universe' escaping from perspective, producing unmediated vision and knowledge. Nature is split from culture. Objectivity is secured. However, this tradition is 'not one but many' (250)

Another scene referring to Schrödinger in 1935, which Barad links to a section in Derrida where living is somehow between life and death, and thus implicated with ghostliness. The cat is superposed in life and death, its fate decided by a radioactive atom. Schrödinger wanted to make a point about measurement, and to point out that we feel sympathy for cats but not for electrons or other 'critters that populate the world of the nonliving', which can include the undead, spooks — that line is one of the most sacrosanct of all.

The atom is itself indeterminate, both having decayed and having not decayed, so the cat must be superposed between alive and dead. 'Before it is observed, there is no determinate fact of the matter about its condition' (251) superposition is one of these nonclassical relations between different possibilities — it does not imply that cats are both alive and dead simultaneously, nor partly one and partly the other [mostly because death and life are defined as exclusive]. All these ideas of identity and being are undone — 'being/becoming is an indeterminate matter'. However when we do take a measurement there is a kind of '"collapse" — or rather, resolution… Into a determinate state', but we may have no calculable means to understand this. [Penrose rejected then].

Entanglements are 'generalised quantum superpositions', not the intertwining of two or more states, but 'calling into question the very nature of two-ness' and oneness. 'Between' needs to change as well. Commonsense notions of communication between entities are defied, we need a new 'calculus of response–ability' [both required and inspired by quantum entanglement]

Einstein saw entanglement as spooky action at a distance, but it is even more spooky these days because the action seems to work '"beyond the grave… After the link between objects is broken"', and entanglements have been detected over some geographical distance.

Another scene. Derrida on being haunted, inherent in every concept, stabilised only by 'the movement of exorcism' in conventional ontology. Derrida realises that this is a condition of possibility of an event but also a condition of impossibility — we seem to need experience of the impossible. This also informs our sense of justice.

So light behaves as both a particle and a wave, and so does matter. Waves and particles were previously ontologically distinct. The new empirical evidence threatened 'any consistent understanding of the nature of light'. Böhr address the problem by attending to language (252) how concepts are used and meanings made — what we mean by particle and how can we meaningfully use scientific concepts [including 'how do they matter']. Böhr said we should understand concepts 'to be specific material arrangements of experimental apparatuses' (253) — without apparatus, for example we could not understand the concept of momentum. Any use of concepts outside these material conditions would be unintelligible. When determinate meanings are given to particular concepts, this always produces 'its constitutive exclusion… an equally necessary "complementary" concept which is thereby left outside the domain of intelligibility' [we can logically infer them or induce them, surely?]. Böhr called this complementarity. 'This is how every concept is haunted by its mutually constituted excluded other'. Discourse and materiality are intimately related — and not just because 'writing and speaking are material practices'. If we are to understand concepts in this materialist way, and combine that with quantum discontinuity, we can have no apparatus–independent distinction between subjects and objects. The material–discursive apparatus gives meaning to concepts but also 'enacts a specific cut' between what is observed and the agencies of observation — apparently individual entities are a product of this cut. They do not interact but are co- constituted, the result of 'specific intra-actions'. [Note 1, page 267, says intra-action is the key concept of agential realism, unlike interaction it suggests that distinct entities and agencies emerge from intra-action, that is distinct agencies 'are only distinct in the relational, not an absolute sense… In relation to their mutual entanglement'. This will involve a radical reworking of traditional notions of causality] Boundaries and properties are made determinate, but within  the phenomenon, which does not separate object and agency — similarly, concepts and their objects 'enact the differentiated inseparability that is a phenomenon'. Only interaction produces determinate facts or descriptions. Being is 'not simply present'(254). Mattering involves the 'becoming determinate' of matter and meaning. This also explains impossibility, because interactions 'necessarily entail constitutive exclusions' [but again we veer from this to the joys of 'an irreducible openness'.] The concept breaks the 'binary of stale choices between determinism and free will, past and future'.

Another scene, the two slit experiment by Young, proceeded by a quote from Haraway about the need to look at how the disparate holds itself together without defacing heterogeneity [originally Derrida], and how this leads us to diffraction as heterogeneous history not replication, hence it is a technology '"for making consequential meanings"'.

The two slit experiment. Sound waves from speakers form sonic diffraction patterns [for Young's listeners]. The two slit device is described, and differences in patterns explained. As the audience leaves, it also radiates outwards forming a pattern of bands [this is presumably Barad's imagining]. The ghost of Einstein and Böhr appear, and they both do thought experiments with two slit apparatuses.

Böhr argues that light behaves as both a wave and a particle and that these differences are produced following intra-action with the apparatus [so is Böhr the originator of the term?]. Both Bohr and Einstein agree that entities show a diffraction pattern when seen through a two slit apparatus but disagree about what would happen if we modify the apparatus so as to detect which slit an entity had gone through. For Einstein, this would show how the entity behaves like a particle at  the slit and like a wave at the screen, and this would oppose quantum theory [ontological indeterminacy?]. Böhr thinks that which slit apparatus would stop the entity behaving like a wave, to justify his principle of complementarity [the apparatus and its measurements decide whether the entity behaves like a wave or particle]. Heisenberg agrees with Böhr that reconfiguring the apparatus will disrupt the entity, but otherwise they disagree — Böhr thinks that  measurements do not just disturb what is being measured, but rather that the apparatus itself cuts objects from agencies of observation and these do 'not exist prior to the intra-action' (256) — no determinate features are given. What we are seeing is an entangled phenomenon and when we set up an unmodified two slit apparatus we get a wave phenomenon, while a modified apparatus produces a particle phenomenon — 'entities do not have an inherent fixed nature'. Einstein asks whether the nature of the entity, its ontology actually changes as a result of the experimental apparatus, or whether the argument is that nothing was actually there before being measured [see the objections in the New Scientist articles --what exactly is a measuring apparatus -- anything sentient or did we need humans to come along before particles became waves].

Another scene on Newton and his strange predictions. Derrida spells out what is meant by ghost — where what seems to be the future comes back to provide a sense of dispersion, a feeling that there is more than one [of us]. It settles down to discussion of time in Newton, a deterministic universe with a predictable future, which means, for Barad that 'the future has already happened' (257). He also sees an end of time based on biblical prophecy. This must have been in conflict with his natural philosophy — celestial spirits offering 'a vanishing presence. Re-appearing absence'. This calls into question all his empiricism and positivism, determinism and mechanism — 'other ghosts' undo all of these. For Barad these are 'superpositions, not oppositions. Physics has always been spooked' (258).

Another scene starting with Derrida about presence, and how it can never fully grasp that which will never be, or a past that never been present. Barad quotes herself to say that this is like phenomena never situated in the present because they entangle different acts. We now have 'empirical evidence' that it is possible to change not only the past but being itself when it was in the past.

Technological innovation on the two slit apparatus led to it being capable of deciding between Böhr and Heisenberg in a kind of 'experimental meta/physics'. Heisenberg sees measurements as disturbances, while Böhr sees measurement as a matter of 'semantic and ontic determination' implying indeterminacy in the conventional sense. They disagreements turn on what happens when measurements are absent, before measurements, say.

We can now devise an ingenious experiment. The 'inner workings of the atom (that is, its "internal degrees of freedom")' (259) can leave behind signs of which slit the atom passed through. These do not disturb the forward momentum of the atom '("external degrees of freedom")'. Apparently, we can make an electron jump to release a photon behind at just the right time [by 'tinkering only with the atom's internal degrees of freedom'], while the atom then continues unaffected by this release.

The result was 'unambiguous confirmation of Böhr's point of view'. The which slit detector changes the pattern from diffraction to scatter, wave to particle, but this is 'not a result of disturbance'[because this particular disturbance does not affect the future path of the particle? — It is a 'shift by design']. This apparently clearly shows that the shift in pattern 'is the result of the entanglement of the "object" and the "agencies of observation"'. This is evidence for 'Böhr's performative understanding of identity' — identity is performed differently in different experimental circumstances.

Implications follow. If we modify the which slit detector to erase the sign after the atom has gone through, we find a diffraction pattern again, just as if there were no which slit detector. It doesn't even matter when the information is erased — 'it could be raised after any given atom has already gone through the entire apparatus and made its mark on the screen' (260). Somehow, we have determined the behaviour of the entity after it's gone through the apparatus, after it's gone through as either a wave or a particle already — 'the entities' [sic] very identity has been changed. Its past identity, its ontology is never fixed, it is always open to future reworkings'.

It looks like it's possible to change the past, but early understandings talk about a diffraction pattern this having been recovered, while information had been erased, but these assumptions have been further questioned. They assume 'the metaphysics of presence' where individually determinate objects exhibit behaviour and release information. This is to be rescued from alternatives such as supposing 'instantaneous communication… Spooky action at a distance'. Instead, we have 'empirical evidence for a hauntology'.

The experimenters did not change a past 'that had already been present'. The past was never simply there to begin with. Past and future are 'iteratively reworked and enfolded through the iterative practices of spacetimemattering' (261), and the apparatuses are all included in this phenomenon. Space and time are 'phenomenal, that is, they are interactively produced in the making of phenomena', and do not exist as universals outside of phenomena.

There is further evidence that traces of the event are not erased when information is destroyed. The subsequent diffraction pattern is not the same as the original, for example, but this is not evident without explicit efforts to trace the entanglements. These traces remain when the information is erased and require work to make them visible. This makes the general point that the past is not closed and cannot be fully erased. It follows that '"past" and "future" are iteratively reconfigured and enfolded through the world's ongoing intra-activity'. There is no determinate relationship between them. Phenomena are not separate entities but material entanglements 'enfolded and threaded through the spacetimemattering of the universe'. If a diffraction pattern returns, it has not gone back to restore a past in the present. Memory is a pattern of sedimented enfolding, it is apparent 'in the fabric of the world' — memory is the world, '(enfolded materialisation)'.

Another scene, beginning with Derrida on responsibility attached to inheritance, and justice as responsibility to everything, ghosts who are not born who are already dead [seems he is implying that there is some commitment to the social in general rather than to specific individuals?]

Subsequent deaths in atomic warfare can be seen as ghosts, as can animals, ghostly entanglements with the original Copenhagen physics. Cope and harden itself should not be understood as a simple place, but 'rather a non-place and non-time', a disjuncture or opening. Ethics is more than just rights, blame or innocence [the themes of Frayn's play] it is not a matter of restoring justice to Heisenberg or culpability to Böhr. Frayn says that we will never know Heisenberg's intentions, which might have helped humanity — but once again this is centred on Man. Uncertainty itself does not disrupt the usual story, and it lives only inside the human mind for Frayn.

Heisenberg's paper about uncertainty means he is certain [!] that uncertainty is inevitable in all measurement, but there is a postscript, where this belief falters, and he admits that Böhr is correct about complementarity. Frayn picks this up and makes it a key scene, but misses its importance — irreconcilable disagreements between the two which will affect the whole of the apparently unified Copenhagen interpretation.

The play and the events have fractures and disjunctures rather than unity, haunted by 'ghost that is the very spectre of multiplicity itself' (263). We should see this as pointing to indeterminacy rather than uncertainty, 'hauntological multiplicity' that is not just about Man. What if we played out some of the possible scenarios in Frayn's play, reading them as hauntological not epistemological? We would see that these are indeterminate matters not human uncertainties, showing 'coexisting multiplicities of entangled relations of past–present–future–here–there', that what we take as just things in the present are really 'worldly phenomena', that there were 'iterative materialisations', 'contingent and specific (agential) reconfigurings, including reconfigurings of the past and the continual reopening of what might yet be'.

This aligns with Derrida's view of justice as more than a matter of repairing injustice or trying to work out what must be in the present disjoined time, what a relation to the other presupposes if we no longer understand being and time in the old ways. We can't make amends. We must take ghosts at their word, and see the past is never closed or never finished 'but there is no taking it back, setting time right, putting the world back on its axis… no erasure'. All enfolded materialisations are present in all reconfiguring is. We can't just reconstruct another narrative but instead we must be properly responsible for what we inherit [which is a very abstract way of saying we shouldn't be nasty to earlier thinkers?]. We are entangled. We are not just present. We should risk ourselves and open to indeterminacy in moving toward the future. Responsibility itself is 'an asymmetrical relation/doing, and enactment, a matter of différance, of intra-action, in which no one/no thing is given in advance or ever remains the same'. This is responsibility to the entangled other without easy dismissal.

Entanglements are relations of responsibility with no dividing lines. After quantum theory, 'Cartesian cuts are undone'. Agential cuts are not absolute but also hold together the disparate itself, and thus do not efface heterogeneity [agreeing with Derrida]. Agential separability is produced as well as entangling, relations of joining in this joining are radically reworked. Any agential separability must involve 'irreducible heterogeneity', regardless of 'relations of inheritance' that have produced what we currently take to be disparate. Entanglements are not just 'the interconnectedness of all being as one' but specific material relations showing 'ongoing differentiating', relations of obligation because we are bound to the other and are ourselves 'enfolded traces of othering'. This also depends on the view that 'ethicality entails non-coincidence with oneself'.

Ethics is integral to diffraction, not just 'a super imposing of human values onto the ontology of the world (as if "fact" and "value" of were radically other)'. Matter itself always involves 'an exposure to the Other' [capital letter shows the shift to the most abstract form? --it leads to Note 11 so maybe it means matter itself as well as human others?]. It is not just an obligation but 'an incarnate relation that precedes the intentionality of consciousness' [this same phrase crops up several times].

Responsibility is not a calculation but an integral relation to the world and its becoming, and opening up to 'an enabling of responsiveness'. It's based on the whole 'iterative reworking of im/possibility', connected to a topological notion of 'respons-ibility' [sic, with an i].

For Derrida, inheritance is not simply given but is something that relates to our questions of being a subject, our very being. We need an ethics of entanglement to uncover 'possibilities and obligations for reworking the material effects of the past and the future' (266). As in the quantum eraser experiment, there is no given past to be changed, because the past is already open to change. 'There can never be complete redemption' but we can reconfigure spacetimematter as we realise new possibilities and impossibilities. We still have marks on our bodies, on the flesh of the world. We have a debt to those who are dead and those not yet born, and this is who we are. It follows that 'differentiating is a material act ...is not about radical separation, but on the contrary, about making connections and commitments'.

Note 2 (267) says that this paper is diffracted through the book, and notes that there are 'multiple interpretations of quantum physics' – and then she gives some references. Note 7 (268) says that making sense is a material matter, that we have material obligations 'bound by responsibility'. It goes on to say that matter is not as Newton or Marx imagined it, separate from the meanings of language, but rather has 'a general textuality', enabling us to rework both materiality and discursive beauty. Note 8 explains that Heisenberg's motives were not just unclear, but were 'multiple, indeterminate, spooked, not his alone'. Note 9 says that agential cuts can always be iteratively reworked, for example undoing inside and outside. Constitutive exclusions are the conditions of possibility for this openness, so we have 'an uncanny topology: no smooth surfaces, willies everywhere' [weird]. Differences in habit everything and they are always being reworked and reconfigured, threaded through each other. Note 10 refers to Levinas on responsibility as the key to ethics, and Barad says her book tries to do without 'the humanist foundations that have been an integral part of L's philosophy. Note 11 says that matter is dynamic, agential, always reconfiguring, so that deconstruction is not a human method or technique, but rather 'what the text does, what matter does, how mattering performs itself'. This means it is 'ongoing hauntological transformation' nature itself 'rights, scribbles, experiments, calculates, thinks, breathes and laughs' with a reference to something by Kirby forthcoming. Note 12 insists that it is not just one possibility realised in actuality — 'rather, im/possibilities are reconfigured and reconfiguring with each intra-action' [so no compossibility -- at least in principle].

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