EDELMAN J.
Introduction
Even with the benefit of omniscience, God still afforded Adam the benefit of the natural justice hearing rule. That rule has long been understood to be a foundational principle of justice. When statute creates a decision-making process, the usual implication that would be drawn by any reasonable reader from the language is that the hearing will follow a procedure that is fair in light of the relevant provisions. It would require words of extreme clarity before a court could conclude that Parliament intended to create a process that permitted a statutory hearing process to proceed unfairly.
At the heart of this appeal is whether s 473DA(1) of the Migration Act 1958 (Cth) excludes the ordinary manner in which implications are drawn or whether it provides, as it says, that the relevant ("exhaustive") provisions to consider for an implication of "the natural justice hearing rule in relation to reviews conducted by the Immigration Assessment Authority" are those contained in the same Division as well as ss 473GA and 473GB. The implication would then be assessed in the ordinary manner but without recourse to other provisions.
The facts and background to this appeal are set out in the joint reasons for decision of the other members of this Court. I agree with those reasons for dismissing the second ground of appeal, concerning the alleged inference that the Immigration Assessment Authority ("the Authority") failed to consider exercising the discretion conferred by s 473GB(3)(b) of the Migration Act. I also agree with the conclusion reached in relation to the first ground of appeal, but for different reasons. In my view, s 473DA(1) of the Migration Act does not impliedly alter the underlying principles of statutory interpretation so as to preclude any implication of procedural fairness based on the natural justice hearing rule. Instead, I would dismiss the first ground of appeal because there was no practical unfairness to the appellant.
When statutory words exclude procedural fairness
When a decision‑maker exercises a statutory power that would affect the rights or liabilities of another person, questions arise as to how that power should be exercised. The "hearing rule" is an expression, or more commonly an implication, in a statute of a requirement of procedural fairness in the exercise of that statutory power. The implication will always depend upon the legislative intention; although where a power is conferred without express qualification, it will usually involve an implication that the power be exercised by respecting those requirements of justice that natural reason would require having regard to all of the circumstances. At a high level of generality, one of the requirements that will inform the terms of any implication, subject to the terms and context of the statutory power, will often be the principle based upon conventional assumptions to which the common law gives effect that a person should have a "reasonable opportunity of presenting [their] case".
The threshold question on this appeal is whether s 473DA(1) of the Migration Act excludes any implication that would otherwise arise from the words of the statute in their context giving effect to a reasonable opportunity for an applicant to present their case, when any of the powers in Div 3 of Pt 7AA, s 473GA, or s 473GB are exercised by the Authority. Section 473DA(1) of the Migration Act provides:
"This Division, together with sections 473GA and 473GB, is taken to be an exhaustive statement of the requirements of the natural justice hearing rule in relation to reviews conducted by the Immigration Assessment Authority."
There is an immediate difficulty in interpreting s 473DA(1) as drawing a conceptual distinction within Div 3 and ss 473GA and 473GB between (i) express terms that impose duties that fall within the classification of the natural justice hearing rule, and (ii) implied terms that fall within that classification. That difficulty, which has been identified in the context of contractual instruments, is that it "flies in the face of our experience of the way language is used" to create a "conceptual difference between construing the meaning of the words used ... and implying a term". As O'Connor J put it, "[e]very implication which the law makes is embodied in the contract just as effectively as if it were written therein in express language". Since the legislative intention from which a statutory implication is made also depends on context, including the common law background to the statutory words, "a debate whether procedural fairness is to be identified as a common law duty or as an implication from statute proceeds upon a false dichotomy and is unproductive". Hence, in Kioa v West, Brennan J did not separate expression and implication when his Honour described the "procedural requirements ... expressly or impliedly prescribed by statute" as a question of interpretation that "demands a universal answer", albeit an answer which would be applied in a manner that would vary according to the circumstances of the case.
In the context of Div 3 of Pt 7AA, there could be serious difficulties in drawing lines between express requirements of procedural fairness such as those in s 473DE(1) and implied requirements. For instance, when the Authority exercises its powers in relation to s 473DE(1), are matters such as (i) limits to the way the Authority thinks it appropriate to "give" the particulars of the new information, (ii) the extent of the particulars, or (iii) the manner of giving an invitation to comment on the new information, matters that are implied against the background of common law principles in light of which they were enacted, or matters that are an application of the express terms, or both? Ultimately, this issue can be put to one side because neither the semantic meaning nor the context of s 473DA(1) has the effect of excluding any implication that would be drawn from Div 3, s 473GA, or s 473GB to give effect to procedural fairness.
The semantic meaning of the words of s 473DA(1) does not exclude an implication to give effect to the natural justice hearing rule when powers in Div 3 of Pt 7AA or ss 473GA and 473GB are exercised. Rather, the plain meaning of the words of s 473DA(1) is that the relevant provisions are the only provisions from which any obligations that could be characterised as part of the natural justice hearing rule could be expressed or implied for reviews conducted by the Authority.
Nor does the context in which this provision was enacted suggest the exclusion of procedural fairness implications in the exercise of powers by the Authority within Div 3 of Pt 7AA, s 473GA, or s 473GB. The words of s 473DA(1) are very similar to those of ss 51A, 97A, 118A, 127A, 357A, and 422B, which were inserted by items 1-6 of Sch 1 to the Migration Legislation Amendment (Procedural Fairness) Act 2002 (Cth) and commenced on 4 July 2002 ("the 2002 Provisions"). Each of the 2002 Provisions provides that various other provisions, Divisions, or Subdivisions are "taken to be an exhaustive statement of the requirements of the natural justice hearing rule in relation to the matters they deal with" or "the matters it deals with". These words have been held to be "consistent with the implication of an obligation to afford procedural fairness". They do not exclude an implication that would otherwise be drawn from the provisions to which they refer.
There is one linguistic difference between the 2002 Provisions and s 473DA(1). The 2002 Provisions are expressed to apply "in relation to the matters they deal with" rather than, as s 473DA(1) was expressed in 2014, "in relation to reviews conducted by the Immigration Assessment Authority". But this difference concerns the range of matters that are the subject of the procedural fairness obligation. It is not concerned with any distinction between express and implied terms. Part 7AA limits the sources from which any hearing rule procedural fairness implication can be drawn in a hearing by the Authority to the provisions mentioned. Similarly, the reference in s 473DA(1) to "reviews conducted by the Immigration Assessment Authority" means "in relation to all subject matters dealt with by the Immigration Assessment Authority" in reviews under Pt 7AA. In contrast, the 2002 Provisions do not limit the entirety of the hearing rule procedural fairness obligations before the Administrative Appeals Tribunal ("the Tribunal"). Each of the 2002 Provisions constrains the Tribunal to confine its assessment of any express or implied obligations of procedural fairness to the subject matter of those provisions.
This meaning of s 473DA(1) is confirmed by the use of the same words as the 2002 Provisions in the Explanatory Memorandum to the Migration and Maritime Powers Legislation Amendment (Resolving the Asylum Legacy Caseload) Act 2014 (Cth), which by item 21 of Sch 4 inserted Pt 7AA, including s 473DA, into the Migration Act:
"The purpose of this amendment is to make clear that sections 473GA, 473GB and Division 3 of Part 7AA of the Migration Act are an exhaustive statement of the requirements of the natural justice hearing rule in relation to the matters they deal with. Division 3 sets out how the IAA should conduct its review and outlines how the IAA is to review decisions on the papers and provides limits on the consideration of new information for the purposes of making a decision in relation to a fast track reviewable decision. Section[s] 473GA and 473GB deal with the disclosure of confidential information to and by the IAA." (emphasis added)
This meaning is also supported by s 473DA(2) and the interpretation that has been given to that sub‑section. That sub‑section, "[t]o avoid doubt", relevantly provides that "nothing in this Part requires the Immigration Assessment Authority to give to a referred applicant any material that was before the Minister when the Minister made the decision under section 65". Section 473DA(2) has been confined to implications requiring the giving of such material that would be drawn only from the natural justice hearing rule. But it does not exclude all implications, including implications that would require the Authority to give the referred applicant other material.
The legislative intention underlying s 473DA(2) is to confirm beyond doubt that a particular, pertinent implication should not be drawn from the provisions in Pt 7AA. The premise of s 473DA(2) is that since implications might be drawn from the principles of the natural justice hearing rule it was necessary to remove any doubt about whether this particular implication could be drawn. Hence, when the Explanatory Memorandum explained the purpose of s 473DA(2), it did not say that the sub‑section existed to confirm the exclusion of only one of the many possible implications that were also excluded. Rather, it explained that s 473DA(2) was there to remove doubts that might otherwise have permitted the particular implication of a liberty to comment to be drawn from the relevant provisions. The preferred position, which sought to remove doubt, was that the implication should not be drawn because, as the Explanatory Memorandum said, the applicant had already been given an opportunity to comment:
"The purpose of [s 473DA(2)] is to put beyond doubt that the IAA is not required to give a referred applicant any material that was before the Minister for comment. This is because under subsection 57(2) of the Migration Act and in relation to their fast track decision, an applicant would have already been provided an opportunity to comment on relevant information that the Minister considered was the reason, or part of the reason for refusing to grant a visa."
The principle of legality is a further reason why the words of s 473DA(1) should not be strained to reach a conclusion that any implication of procedural fairness is excluded. That principle usually represents the natural process of reasoning that the more important or fundamental a person's right, and the greater the alleged adverse effect on the right, the less likely it is that Parliament would have intended that effect, and the clearer the words that are required to achieve it. It is, perhaps unsurprisingly, a principle that is pertinent when considerations of the legality of executive action are concerned. Implications that are based upon principles of natural justice are important liberties that have been held only to be excluded by "plain words of necessary intendment", and not by "indirect references, uncertain inferences or equivocal considerations".
The Minister submitted, however, that the exclusion could be drawn from the statement appearing in s 422B, but not in s 473DA, that "[i]n applying this Division, the Tribunal must act in a way that is fair and just". In effect, the Minister's submission was that the absence of an express reference to acting fairly and justly in s 473DA implied that the Authority was empowered to act in a way that was unfair or unjust in the exercise of its powers even if the natural implication to draw from the relevant provision was to the contrary. That submission cannot be accepted. There is a convention of language that omission of a matter that is expressly mentioned elsewhere can imply its absence. But the force of this convention depends entirely on context. Here, a person's right to a reasonable opportunity to present a case, if naturally implied as part of a decision‑maker's powers, is not an aspect of procedural fairness that can usually be abolished by Parliament by a nudge and a wink.
In summary, s 473DA(1) does not say that "in the process of interpreting the meaning of Div 3 of Pt 7AA and ss 473GA and 473GB, a court cannot draw any implication that would require conduct to give a person a reasonable opportunity to present a case". What s 473DA(1) does, however, is exclude from consideration, for any implication, those terms and provisions outside Div 3 of Pt 7AA or ss 473GA and 473GB. It precludes from the consideration of what procedural fairness requires in "reviews conducted by the Immigration Assessment Authority" any other legislative provisions, such as s 473FB in Div 5, which concerns practice directions issued by the President.
The limited implications of procedural fairness and unreasonableness in s 473GB
The only provision from which the appellant sought to draw an implication of procedural fairness, requiring disclosure to him that the Authority had received material that was the subject of a certificate, was s 473GB(3). Section 473GB(3) provides:
"If the Immigration Assessment Authority is given a document or information and is notified that this section applies in relation to it, the Authority:
(a) may, for the purpose of the exercise of its powers in relation to a fast track reviewable decision in respect of a referred applicant, have regard to any matter contained in the document, or to the information; and
(b) may, if the Authority thinks it appropriate to do so having regard to any advice given by the Secretary under subsection (2), disclose any matter contained in the document, or the information, to the referred applicant."
The "document or information" to which s 473GB(3) refers is not the written certificate. The certificate is issued under s 473GB(5) to certify that the disclosure of any matter contained in the document, or the disclosure of the information, would be contrary to the public interest for reasons, broadly, of public interest immunity or confidentiality.
Section 473GB(3) does not expressly require the Authority to disclose any matter contained in the document, or the information, to the referred applicant. However, the appellant submitted that s 473GB(3) contained an implied power to disclose to him that a certificate had been issued and a duty to do so where procedural fairness required.
Although the Minister had submitted that any such implication of procedural fairness had been excluded by s 473DA(1), the Minister accepted that s 473DA(1) had not excluded a requirement that the Authority must act according to an implied requirement of legal reasonableness in exercising its powers under s 473GB(3). In other words, even if any implication of procedural fairness were excluded by s 473DA(1), an implication with almost precisely the same content could be implied as a requirement of legal reasonableness.
It is hard to imagine any circumstance in which the exercise of a power in a manner contrary to the requirements of procedural fairness that would be implied but for the purported exclusion by s 473DA(1) would not be legally unreasonable. However, in light of the conclusion I have reached about the proper interpretation of s 473DA(1), it is not necessary to consider the extent to which the acceptance of possible implications of legal reasonableness which might encompass the entirety of any duty of procedural fairness casts doubt upon whether Parliament would have intended to exclude an implication of the latter.
It can be assumed for the purposes of this appeal that the Authority has a power to disclose that a certificate had been issued in addition to the power to disclose information or documents that are the subject of the certificate. It might be expected that a duty to exercise that power in order to give procedural fairness to an applicant would arise only in exceptional circumstances. However, one circumstance where the effective functioning of s 473GB(3) might arguably require the exercise of the power to disclose that a certificate had been issued is if it is necessary to obtain submissions from an applicant concerning whether there should be disclosure of information that is the subject of the certificate.
It suffices for the purposes of this appeal to assume both the existence of that power and a duty to exercise it where necessary to give applicants a reasonable opportunity to present a case. Even on this assumption there was no duty for the Authority to disclose the existence of the certificate in this case.
Unfairness, unreasonableness and materiality
In written submissions, a focus of the Minister was upon whether any procedural unfairness or unreasonableness arising from a failure to disclose the existence of the certificate was material. However, he accepted in oral submissions that there is an anterior issue to materiality. This is whether the failure to disclose was unfair or unreasonable.
Both "unfair" and "unreasonable" are relative terms. For an exercise of power to be procedurally unfair there must be sufficient "practical injustice" in the departure from the procedure impliedly required by the statute. For an exercise of power to be legally unreasonable it must be unreasonable to the degree required by the statutory implication. It is only where an irregularity reaches the threshold of practical unfairness or the required statutory standard of unreasonableness that the question of materiality arises. Then, for a finding of jurisdictional error, materiality requires consideration of (i) whether the conduct involved a fundamental irregularity, or, if not, (ii) whether, despite the unfairness or unreasonableness, the result would not inevitably have been the same or, put another way, there was a possibility of a successful outcome. There may, however, be circumstances where a discretion might nevertheless be exercised to refuse a new hearing, including practical reasons that have subsequently arisen that would make a new hearing futile.
Subject to issues concerning the substantive or evidentiary onus of proof the same basic reasoning has long applied in relation to the proviso in criminal appeals, where the adjective "substantial" is often used in place of "material". In most formulations of the common appeal provisions, an appeal will not be allowed unless there is a miscarriage of justice and it is not established that the miscarriage is not substantial. The miscarriage is not substantial if the error was not fundamental and the result of the appeal would inevitably have been the same. Again, there can be reasons why discretion might nevertheless be exercised not to grant a new trial.
The important point for this appeal is that in this process the anterior question to whether an error is jurisdictional, or whether a miscarriage of justice is substantial, is whether the action or error qualifies as legally unjust or legally unreasonable or, in the language of the criminal law, a miscarriage of justice. It was not asserted in this Court that the failure of the Authority to disclose to the appellant that it had received material that was the subject of a certificate was a jurisdictional error due to legal unreasonableness. The failure did not reach the sufficient threshold of unreasonableness. Nor did it reach the required threshold of legal unfairness. The failure to inform the appellant of the existence of the certificate did not affect the manner in which the review was conducted. The fact of the existence of the certificate would not have revealed to the appellant anything new about the subject matter to which the certificate related. It would not have revealed to the appellant anything about his brother's evidence or omissions from that evidence, and would not have revealed any significance that the Authority might have placed on that evidence or those omissions.
Conclusion
For these reasons the first ground of appeal must be dismissed. I agree with the reasons of the joint judgment for dismissing the second ground of appeal, and with the orders proposed in the joint judgment.