Indistinguishability — Two things that cannot be told apart

On this pageThis page in one paragraph · What is this form? · What does Dost say? …
  1. This page in one paragraph
  2. What is this form?
  3. What does Dost say?
  4. What is there in physics?
  5. Hong 1987 — Two photons, one mirror
  6. SEP 2024 — Identity and individuality in quantum theory
  7. What does the secondary literature say?
  8. Looking side by side
  9. Questions we are left with
  10. What did we not do?

This page in one paragraph

On this page we ask this: when the pairs Dost calls "neither the same nor other" (servant and al-Haqq, the image in the mirror and the one looking) are set side by side with the identical particles of physics that cannot be told apart, is the failure of the question "which is which" to hold in both a situation of the same kind? The one line we looked at is servant and al-Haqq ↔ identical particles; we left this line as "greeting from a distance." Where they greet each other is this: two identical photons always leave the beam splitter together, and indistinguishability makes a measurable difference [Hong 1987]. Where they part is also clear: in physics two things that cannot be told apart are identical, whereas in Dost the two sides are not counted as identical, one is in the likeness or the veil of the other. The side that stays farthest is doors such as the owner of the act and of the will: we found no category in physics where they could sit, and some doors we did not look at at all on this page. The open question is this: does Dost's "two things that cannot be told apart" also make a difference, and if so, where?

What is this form?

Let us think for a moment: there are two things, but when we ask "which is this, which is that," the question itself finds no place to stand. Are the two one? No, because we speak of two. Are the two two? Not quite that either, because there is no trace to tell one from the other. Here we call this Indistinguishability: two things that cannot be told apart.

In Dost's writing this form meets us very often. In the section summaries we read, 282 items fit this pattern. Servant and al-Haqq, the image in the mirror and the one looking, the veil and the veiled, the one who does the act and the place where the act appears: always a pair, always "neither the same nor other." For this reason Indistinguishability is one of Dost's most crowded doors.

What we try to do on this page is this: to explain this manner of Dost's speaking in plain words, then to look at two things known in physics as "indistinguishable," and to put the two side by side and ask a question. We will not give an answer. An eye that reads may notice a place we could not see; we wrote the page leaving room for that eye as well.

What does Dost say?

«My servant draws near to Me with supererogatory acts of worship, until I love him; when I love him, I become his hearing, his sight and his supported hand» (c10k133, p. 366)

This is the well-known hadith qudsi. The servant's hearing, seeing, grasping are not described as something separate from al-Haqq; but the servant has not disappeared either, the hadith goes on calling him "My servant." What to note: the servant continues to be called "My servant" in the hadith as well; the hadith describes the relation between al-Haqq and the servant, it does not put the two in the same category, and the page does not either.

«Absolute nonexistence is a mirror before absolute existence. Existence sees its own image in the mirror. In this case that image is the possible itself… It is neither the one who sees nor other than him!» (c11k135, p. 65-67)

Here the mirror is a means of expression: the image in the mirror resembles the one looking, but it is not the looker himself either. The text leaves it as "it is neither the one who sees nor other than him." The saying does not end with a "yes" or a "no," it ends by rejecting both options. This pattern "neither that nor other than that" seems to resemble a formula also known in kalām (lâ huwa wa lâ ghayruhu); we did not read that context separately.

«This is like the image of the person looking into the mirror. The image in the mirror is neither the same as the image of the person looking nor other than him» (c11k139, p. 227-228)

The same idea, in another section, is told this time directly with an everyday scene. When we look into a mirror, the face we see is not our face, but it is not independent of us either. What to note: Dost says this relation in two places, in two different sections, with the same pattern; it does not seem a coincidence.

«The perfect human and Allah too are in a likeness descending to the station of intertwining (iltifaf)» (c10k127, p. 98)

"Iltifaf" is something like being wound into one another. The section says that the letters lam and alif are inseparable in writing, standing almost like a single letter. What to note: here too it is not said "one," it is said two sides, like two letters wound into each other.

«So you are, from yourself, His veil. Remove yourself, that the matter may become easy!» (c12k146, p. 235)

The veil is as much what shows as what hides. Here the veil is "you" yourself; that is, the dividing line is not outside. What to note: what makes the separation is inside the two sides that are separated.

«That the child is the same as his own parent is one of the strangest secrets» (c10k130, p. 237-238)

The section recalls al-Hallaj's saying "My mother gave birth to my father" and names this strangeness a secret. What to note: as though the one who gives birth and the one born have changed places; the question "who from whom" finds no footing in this sentence either.

What is there in physics?

Hong 1987 — Two photons, one mirror

Let us imagine sending two particles of light (photons) at the same moment, from two separate sides, onto a half-transparent mirror. By an everyday calculation four outcomes are expected: both to one side, both to the other side, or each to a separate side. Quantum theory, however, says that if the photons are completely identical to each other, the possibilities of "coming out separately" cancel each other; the two always leave together from the same exit. Hong, Ou and Mandel measured this. When the small difference between the arrival times of the photons was adjusted, the number of times a signal was received at both detectors at once collapsed when the photons coincided exactly. The width of this collapse gave the "length" of the photons in time as about a hundred femtoseconds (on the order of a ten-quadrillionth of a second). This is an experimental result and a very solid one. The point that gives one pause is this: when two particles become indistinguishable from each other, a measurable difference appears; that is, "not being able to tell apart" is not an empty word. [Hong 1987]

SEP 2024 — Identity and individuality in quantum theory

This is not an experiment, it is a philosophical review entry. The question is this: does quantum physics allow us to look at particles as separate individuals that we can call "this one" and "that one"? According to the entry, the view that became widespread at the time the theory was built holds that elementary particles cannot be counted as individuals in this sense. Accordingly, special logical systems have been developed that do not count individuals and that build the concept of "identity" in another way. On the other hand, it has been argued that quantum physics may still be compatible with a metaphysics that speaks of individuals; but in that case the individuals are so indistinguishable from each other that Leibniz's principle of the "identity of indiscernibles" would be violated. This claim too has been objected to. So there is no definite conclusion here, the debate continues. What gives one pause is that for two electrons the question "which is which" can lose its meaning. [SEP: Identity and Individuality in Quantum Theory]

What does the secondary literature say?

According to the SEP entry, Ibn Arabi stresses this for the imagination (khayal)/image: the image unites two sides and is both the same as and different from each of the two. In the examples the entry gives, the reflection in a mirror is both the mirror and the object it reflects, or neither the mirror nor the object; a dream too is both the self (nafs) and the thing seen, or neither. The entry summarizes this as "it is / it is not" and ties the same structure to the concept of barzakh, which both separates and joins two things, for example the "line" that separates the sun from the shadow. This paragraph is not Dost's word, it is the account of the secondary literature. [SEP: Ibn 'Arabi]

Looking side by side

Servant and al-Haqq ↔ identical particles. Greeting from a distance. What is shared is this: on both sides there is the feeling "there are two things but when we ask which is which the question finds no footing." In Dost, servant and al-Haqq give this feeling with sayings like "I become his hearing, his sight, his hand" and "neither the same nor other." In physics two identical photons, because they cannot be separated as "which is which," always leave the beam splitter together [Hong 1987]; the philosophy entry also discusses that for two electrons this question may lose its meaning [SEP: Identity and Individuality in Quantum Theory].

Where they part is large. In physics this is a measurable situation, tied to the principle of symmetry and to the statistics of particles. In Dost the relation described is between servant and al-Haqq, concerning being itself. Where one who sees can notice: in physics indistinguishability is between two identical things; in Dost the two sides are not counted as identical, one is in the likeness or the veil of the other. If this difference is overlooked, the closeness would be misleading.

The question we are left with: in physics indistinguishability makes a measurable difference (two photons always leave together). Does Dost's "two things that cannot be told apart" also make a difference, and if so, where?

Neither the same nor other; opposites together. We did not take up this line here. "Neither the same nor other" and the counting of two opposites as true together fall closer to the idea of complementarity that we looked at on another page; it was written there. We did not repeat it on this page.

The owner of the act and of the will. We did not look at this door. Sayings such as "if you say this act belongs to Allah it is right, if you say it belongs to the created it is still right" are very important, but we could not find a category in physics for them to sit on. Not finding one is also a result: the broad part of this form in Dost does not match physics.

I, He, you: address that changes places. We did not look at this door on this page; the right place for the question is the Relation page.

Mirror, veil, the seer and the seen. We did not look at this door on this page; its real place is the Viewpoint page.

Knowledge, the knower, the known. We did not look at this door on this page; its real place is the Knowledge page.

Who speaks and who listens; the lending of being in the servant; change of image. We did not look at this door. These seemed not to correspond to anywhere in physics. One who sees may think differently.

Questions we are left with

What did we not do?

We did not compare Dost's words with the Arabic original; what we read is the Turkish section summaries on our site and the quotations taken from them. We also described the physics sources only through their plain-language summaries.

This page is not a reading summary, it is our own frame of reading; we do not understand Dost, and we do not give up trying to understand.

Translation check. Of the difficulty-3 items in this form that carry a quotation, 269 were checked against the text of the Futuhat translation (Ekrem Demirli): 243 were found in the translation, 12 partly, 14 not found. “Not found” may point not to an error but to OCR damage or to the summary's own wording; each one is to be looked at individually. No comparison was made with the Arabic original.