(As we discussed yesterday, the Majority judgment in Aadhaar is founded on a set of factual assumptions. We will, therefore, be running a series of four guest posts by Anand Venkat focusing solely on the factual claims that underly the judgment. The first of the four-part series is on the claim that biometric authentication is “unique identification”.)

How do you arrive at scientific truth? There are two distinct approaches: via positiva, or via negativa. Modern science proceeds mostly through via negativa, and a philosophy of falsifiability. A statement which is not falsifiable through observation, evidence or logic is just a conjecture. Prescribed methodologies and peer reviews are used to examine evidence about a scientific statement to ascertain how truthful it is within the boundaries of the experiment.

Why is this important and relevant for an analysis on the Aadhaar judgement?

It turns out that the majority opinion that upheld the constitutional validity of the Aadhaar project did so by a fundamental misunderstanding of not only the science behind biometrics, but also about science itself.  

This post will constrain itself to the factual and technical aspects of the Aadhaar judgement and specifically about biometric uniqueness.

I am Unique (vs) My biometrics are unique

The statement “I am Unique” needs careful examination. If I lose both my hands, in an unfortunate accident, Am I still unique?

What if I lose my eyes? Am I still Unique?

Why am I still unique, even after losing my eyes and arms? Where does my uniqueness come from? Does it come from parts of my body? Or does it come from the sum total of all my experiences, my genetic lineage, my social relationships and hence from the space in my mind, that exist independent of anything else?

This question is important because the Majority opinion has conflated two independent concepts in its opening line – Identity and Identification and thus asserts that “Aadhaar is Unique Identity” and Being Unique makes you the only one.

The basic assumption behind the opinion follows the logical thought process as described below:

  • Every human being is unique.
  • Every human being has a unique set of biometrics, which when considered together is unique and does not exist in any other human, born before or after for all time.
  • A technological solution (Aadhaar) hence can thus be devised to create a unique pattern for any human across all time, which can be mapped to a number.

The first scientific problem that the above reasoning presents is the issue of proof. If a statement is presented as true across all time and is applicable for every human ever born or will be born, how can it be proven “via positiva”? Clearly the only way to make a positive proof of the above statement would be to collect biometrics of every human ever born and will be born, and show that they are unique via empirical data. That would of course be an impossible exercise, which the UIDAI (or any one else) would be foolish to attempt.

One other approach for “via positiva” is however possible. An experiment could be designed to assert that specific fact for a small set of population, and a mathematical formalism could be used to extrapolate it for all population, across all time.

The extrapolation approach, however, can’t be certain about the fact since it uses small samples to arrive at conclusions for all population, across all time and hence must always be qualified with “error rates” or “confidence intervals”. In other words, all via positiva approaches that use extrapolation, are “probabilistic truth” and not “deterministic truth”.

The scientific issues then become:

  • Are these “confidence intervals” overstated or understated?
  • Are the mathematical formalisms used for extrapolation accurate?

Since the questions are crucial, we need to consider the evidence presented by both the Petitioners and the Respondents to the court, and also analyze, how the court came to the specific conclusion in paragraph 55, that “When it comes to obtaining Aadhaar card, there is no possibility of obtaining duplicate card”

Legal pronouncements and Mathematical theorems

There are two specific methods in science to prove facts.

  • Empirical evidence (Not all swans are black)
  • Mathematical proof (using formal logic)

Let us now examine how the majority can claim with complete certainty “there is no possibility of obtaining duplicate card”.

The petitioners provided empirical evidence to the court that UIDAI itself has acknowledged that as early as 2012 (Page 4), that 0.035% of duplicate enrollments, will have “more than one Aadhaar number”. Further the Planning commission in its report had acknowledged that 34,015 Aadhaar numbers were detected as biometric duplicates.

The planning commission report had this Q&A which is reproduced here in full (sic)

Question:  Does UIDAI assure 100% duplicate free database? Will there be no duplicate aadhaar numbers?

Answer: Biometric matching systems or de-duplication systems are essentially based on pattern matching and can be designed to achieve an accuracy of more than 99%. Higher the quality of biometric capture, lesser the probability of a duplicate being generated. However UIDAI aims for inclusiveness so that failure to enroll is negligible. Therefore generation of duplicate aadhaar number cannot be ruled out totally.

The UIDAI’s reply to an RTI request on 2016 is even more damning. It acknowledged that 1.69 Lakh duplicate Aadhaar numbers were cancelled.

The petitioners further provided for the court’s perusal, a mathematical proof written by Hans Varghese Mathews of CIS India and published in EPW after extensive peer reviews. While the UIDAI claimed that it’s error rate, will be fixed across all time at 0.057% (Page 4), Hans’ paper found out that false positives increase over time and will touch 1%, when 100 crores have enrolled and will keep increasing over time.

Further empirical evidence of the accuracy of Hans’ predictions was provided by the UIDAI itself and is summarized in the table below.


This specific question put forth by Mr. Shyam Divan during oral argument to the UIDAI and the responses provided are as follows:

What are the total number of biometric De-duplication rejections that have taken place till date? In case an enrolment is rejected either for: (a) duplicate enrolment and (b) other technical reason under Regulation 14 of the Aadhaar Enrolment Regulations, what happens to the data packet that contains the stored biometric and demographic information?
Ans.: The total number of biometric de-duplication rejections that have taken place are 6.91 crores as on March 21, 2018. These figures do not pertain to the number of unique individuals who have been denied Aadhaar enrolment resulting in no Aadhaar issued to them. This figure merely pertains to the number of applications which have been identified by the Aadhaar de-duplication system as having matching biometrics to an existing Aadhaar number holder.The biometric de-duplication system is designed to identify as duplicate those cases where any one of the biometrics (ten fingers and two irises) match. However, very often it is found that all the biometrics match. It is highly improbable for the biometrics to match unless the same person has applied again.

Let us examine the UIDAI’s response here very carefully. It uses the word “highly improbable” which for an untrained eye is the same as “impossible”. However the word “probable” itself has a precise scientific meaning and is usually accompanied by a numerical figure.

For instance, to clear a sample question paper on CBSE 10th standard mathematics, a student has to not only understand “probable”, but also learn how to compute a number to attach it with the term and get it right from first principles.


How was the UIDAI allowed to get away without qualifying the word “improbable” by attaching a number, when even a school going child attempting a 10th standard mathematics question would be denied marks for a similar answer? More importantly, why did the majority chose not to engage with the “probability” argument at all?

While it is merely baffling that the majority chose not to engage with both the empirical evidence and mathematical formulations that buttress each other, provided by the petitioners, it is stunning that it asserted that a specific scientific statement is true, even when the respondents (Union of india) explicitly said in multiple forums, that it is not true.

And, most importantly, there can be no argument that these issues were not put to the Court. Not only are they on the oral record, but they find explicit acknowledgment in Justice Chandrachud’s dissenting opinion, where the constitutional arguments are grounded in the acknowledgment that biometric authentication is a fallible science.


The Aadhaar project is a biometric technological regime at its heart and mathematical theories and empirical evidence that lie beneath it require a deep engagement to arrive at the correct factual understanding of its perceived failures or success.

When generations of people’s lives are at stake, the least that the majority could have done is to understand the science and mathematics behind biometric de-duplication through careful engagement with the evidence. It is disappointing that it chose to make up its own facts and then believe it.

In terms of the magnitude of error,  “there is no possibility of obtaining duplicate card” comes very close to the church declaring that “The Sun moves around the earth” because it feared the consequences of the scientific truth and could not bring itself to face the simple fact that, its understanding of the world has irrevocably changed.

Scientific facts however do not change or become false, because a constitutional court declares them so, just like the church’s pronouncement did not change the basic fact that “Earth moves around the sun”.

The majority’s refusal to engage and face inconvenient scientific facts is a recurring theme in the Aadhaar judgement and further posts will point out these areas in great detail.

(Editor’s Note: It may be argued that this is attacking a straw-man: nothing in the world is “certain”. The point, however, is that this is how the Majority chooses to frame the issue. And this is no accident: the Majority uses the language of certainty to evade engaging in the hard constitutional enquiries about necessity and proportionality – something that becomes evident when we see how the dissenting opinion engages with these issues. Yes, the Majority could have said that biometric authentication is fallible, but that – all things considered – it is necessary and proportionate in this case. We would then be having a different argument today. But the Majority didn’t say that. It used the language of impossibility (of duplicates) and “unparalleled” accuracy, and shut out the constitutional enquiry on that basis. The Majority judgment, therefore, must stand or fall on the hill that it has chosen to die on.)