To prepare this brief reflection on the development of jurisprudence during the fifty years of the Canon Law Society of Great Britain and Ireland, I decided to begin by examining the case-load of the Tribunal for 1957. In those days, it was the Dublin Metropolitan Tribunal, responsible for all kinds of cases within the Archdiocese of Dublin. While twenty-six priests were assigned to a variety of functions within the Tribunal, only two cases of nullity of marriage were considered that year: one dealing with the impediment of impotence, the other dealing with exclusion of the bonum prolis as well as condition and exclusion of the bonum sacramenti. The report for 1967 shows that 14 cases were pending at the Tribunal – the majority with partial or total simulation, one dealt with grave fear, and two were based on amentia. By 1977, the picture had changed completely: of the 90 definitive sentences of that year, more than 60 were based on defect of due discretion – on its own or in combination with inability to assume the essential obligations of marriage. A mere handful of cases dealt with grounds like simulation, grave fear and condition.
This pattern is reflected in the sentences circulated in Matrimonial Decisions which first appeared in 1967: “in the first two volumes almost all the cases were judged on the grounds of partial or total simulation or force and fear. Indeed only one case on ‘psychological’ grounds appears in each of these two volumes, both amentia. … The first decision on the more modern psychological grounds appears in the 1969 volume. The ground breaking decision is an affirmative one c. Brown dated 3rd July 1969 (Westminster), upheld at second instance, Birmingham, c. Humphreys (Dec. 51 and 52). There is also a negative first instance decision c. Humphreys of 16th December 1969. After this the numbers increase exponentially! In 1970 there were sixteen cases tried under this heading, and one other tried under inability to assume the obligations of marriage”.
The early decisions were very much concerned with justifying the very existence of the ground of a grave lack of discretion. Thus, in the aforementioned decision before Brown of 3rd July 1969, the Ponens gives considerable attention to tracing the origins of the concept of due discretion, resting his position firmly on Rotal jurisprudence. He writes: “This discretionary power or judgemental ability relates not merely to a precise act itself, but also to the consequences of the act. This doctrine dates back to St Thomas, and has been developed and explained ever since (cf. Summa Theologiae – Suppl. 43, 2 ad 21; Suppl. 58, 5 ad 1, 2). Despite falling from favour for some time, the Thomistic view is again being expounded. In the context of marriage, it has been appreciated in recent years that what is involved in marriage is not merely an act (matrimonium in fieri) but also the consequences and grave obligations arising from this act (matrimonium in facto esse). The discretionary power or critical faculty spoken of by the decision coram Felici of 6.iv.1954 (S.R.R. Vol. 46, p. 282) relates at least partly to the ability to make practical or evaluative judgements concerning the responsibilities and obligations in marriage. However, in the view of Felici, this discretionary faculty relates more specifically to a person’s ability to undertake the obligations of marriage; whereas the earlier evaluative knowledge (spoken of in the decision coram Wynen) related more to the ability to make ‘ethical, social and aesthetic judgements about marriage’….”. Already in this sentence, it is possible to discern the beginnings of the distinction of the ground of inability to assume the essential obligations of marriage; indeed the formulation of the doubt in the case made explicit reference to this inability – but it was treated as a subset of a lack of due discretion.
Similar justifications for the existence of the grounds of lack of due discretion and inability to assume the essential obligations of marriage are to be found in sentences of the mid-1970s. A good synthesis is provided in a sentence from Liverpool in 1975:
“Wynen in 1941 made an important distinction between the merely conceptual knowledge of marriage and an evaluative knowledge. Conceptual knowledge refers to an understanding of marriage as an institution, the kind that could be acquired by any schoolboy. Evaluative knowledge requires an appreciation of the aesthetic, social, ethical and juridical significance of the marriage bond. In 1954, Felici gave us the distinction between facultas cognoscitiva and facultas critica. Facultas cognoscitiva has to do with the kind of understanding of marriage which could be assimilated by a child. Facultas critica, on the other hand, is an ability to evaluate, assume and indeed fulfil realistically the basic obligations of marriage. This faculty has its genesis usually at the time of puberty and develops thereon. From these two distinctions emerged the well-known plea of lack of due discretion. An evolving jurisprudence has given rise to further distinctions. In the United States the emphasis under this plea has been placed on the judgemental capacity (the evaluative judgement of Wynen). In England, until recently at least, the plea has been understood to include not only the ability to evaluate in personal terms the matrimonial commitment but also to fulfil the basic obligations. It is clear that some people lack the perception to see what everyone else knows, viz. that they have not the capacity to fulfil the basic obligations of marriage”.
Of course, such statements of jurisprudence echoed the judgements of the Roman Rota, providing detailed commentaries on the text of Canon 1081 §2 of the 1917 Code. Occasionally, a case of lack of due discretion acknowledged the jurisprudential origin of the ground in the traditional concept of amentia. The work of the Commission for the Revision of the Code of Canon Law also influenced the writing of sentences that appeared in Matrimonial Decisions: “When, in February 1975, the Pontifical Commission for the Revision of the Code of Canon Law issued the draft text on the Sacraments, it included, under the heading of ‘Matrimonial Consent’, a proposed Canon which would declare, inter alia, that a person is incapable of contracting marriage who suffers from a serious defect of judgmental discretion in respect of the rights and obligations which are mutually exchanged in marriage… This is an attempt – a successful one, the Court feels – to express in the tabloid terminology which is appropriate to a legal code, the jurisprudence on this matter which has been painstakingly evolved in the ecclesiastical Courts over the past half-century or so…”.
The development of jurisprudence was being assisted not just by the circulation of the selection of sentences in Matrimonial Decisions of England and Wales, but also by the publication of sentences and articles in the Canon Law Society Newsletter. A very useful service was provided in the pages of the Newsletter by the translation of some key sentences of the Roman Rota. The appearance of a third instance decision concerning nullity of marriage, judged not by the Roman Rota, but by the Supreme Tribunal of the Apostolic Signatura, evoked great interest among the members of the Society as is clear from a number of comments printed in the Newsletter. The text of the Sentence itself was printed in 1977. The Signatura sentence was very critical of some notions associated with the developing jurisprudence about lack of due discretion and inability to assume the obligations of marriage. Commenting on the sentence, Cyril Murtagh noted:
“In recent years, many articles have appeared which speak of the possibility of the cessation or ‘death’ of a marriage bond, as opposed to the concept of nullity ab initio. Other articles link this cessation with the disappearance of ‘love’… It is understandable that these theories should give rise to uneasiness amongst canonists generally and among such organs of authority as the Signatura. But such theories have found no acceptance in the Tribunals of this country, as a study of MDEW shows… If these theories have been accepted elsewhere as a basis for jurisprudence, then indeed it is making a mockery of nullity procedures reducing the Tribunal to a divorce court, and calling for authoritative intervention. However, authority must never appear to be attempting to lump together with such theories a jurisprudence which (led by the Rota) devotes serious attention to the capacity of persons for the inter-personal relationship of marriage…”.
The fidelity of the jurisprudence of British and Irish Tribunals to that of the Roman Rota was examined and upheld in a very comprehensive study of the matter published in 1982. Helping to guide this jurisprudence were interventions such as that of the Irish Tribunals meeting in 1977:
“If a Court is to conclude to nullity on the ground of ‘inability to fulfil’, it must find, at the time of the marriage:
 G. Read, “1969-1994: Twenty five years of lack of due discretion”, CLSN 100, December 1994, 42.
 Westminster, Decision before Brown, 3rd July 1969, MDEW Vol. 3, 324-325. The Ponens cites a decision coram Felici, 3 December 1957 [RRDec 49, 788], a decision coram Mattioli, 20th December 1962 [RRDec 54, 711], and the ground-breaking decision coram Wynen, 25th February 1941 [RRDec 33, 149].
 Ibid. 328.
 Liverpool, Decision before Mullan, 24th September 1975, MDEW Vol. 11, 300-301.
 Cf. Westminister, before Koenig, 28th October 1976, MDEW Vol. 12, 53.
 Dublin, Decision before Sheehy, 26th March 1976, MDEW Vol. 13, 127.
 Cf. Westminster Case, before Brown 26th February 1976, CLSN 31, December 1976, 41-51; Shrewsbury Case, before Hurley, 7th April 1976, CLSN 31, December 1976, 52-56; Westminster Case, before Brown 28th October 1976, CLSN 32, March 1977, 61-66; Birmingham Case, before Humphreys, 4th February 1977 CLSN 32, March 1977, 67-71; Cardiff Case, before Chidgey, 24th December 1976, CLSN 33, June 1977, 59-68; Westminster Case, before Dunderdale, 27th January 1977, CLSN 34, September 1977, 88-92; Birmingham Case, before Humphreys, 27th July 1978, CLSN 38, September 1978, 29-31.
 Cf. J. Persich, W. B. Cogan, “Re-examination of the Rotal Sentence coram Wynen, 25th February 1941”, CLSN 34, September 1977, 44-87; Rotal Sentence, coram Anné, 22nd July 1969, CLSN 35, December 1977, 31-44; M. Dooley, “Translation of Rotal Sentence coram Agustoni, 20th February 1979, on ‘lack of appreciative knowledge of the reality of marriage’”, CLSN 44, March 1980, 36-57.
 D. Shanahan, “A critique of the Apostolic Signatura Sentence c. Staffa, 29th November 1975”, CLSN 36, March 1978, 31-40; M. Dooley, “A review of the Sentence of the Apostolic Segnatura, 29th November 1975, c. Staffa, and of previous critiques in C.L.S.N.”, CLSN 37, June 1978, 14-36.
 Apostolic Signatura Sentence, 29th November 1975, “Communion of life and love”, CLSN 33, June 1977, 13-39.
 C. Murtagh, “A review of the Sentence of the Apostolic Segnatura of 29.11.1975 coram Staffa”, CLSN 33, June 1977, 39.
 B. McCumiskey, “Inability and its development in Rotal and British-Irish jurisprudential law”, Studia Canonica 16(1982), 241-281.
 “Inability to fulfil essential obligations of marriage: propositions agreed at a meeting of the full-time staff of the Irish Regional Tribunals and of representatives of the National Marriage Appeal Tribunal of Ireland”, CLSN 34, September 1977, 15.
 E.g. Dublin, Decision before Walsh, 15th June 1978, MDGBI, Vol. 17, 107; Dublin, Decision before Stenson, 30th March 1981, MDGBI, Vol. 17, 123.
 E.g. Dublin, before Slevin, 31st December 1984, MDGBI, Vol. 20, 95-99, in which the Ponens gives a lengthy dissertation on the doctrinal and jurisprudential roots of the grounds named in Canon 1095 2° and 3°.
 E.g. Dublin, Decision before Rafferty, 31st March 1975, MDEW Vol. 11, 374-376.
 E.g. Westminster, Decision before Ashdowne, 30th October 1975, MDEW Vol. 11, 333-336.
 E. g. Westminster, Decision before Ashdowne, 20th January 1975, MDEW Vol. 11, 204-207.
 E.g. Dublin, Decision before Sheehy, 17th February 1975, MDEW Vol. 11, 223-224.
 E.g. Westminster, Decision before Ashdowne, 6th October 1975, MDEW Vol. 11, 197-199.
 E.g. Westminster, Decision before Brown, 28th August 1975, MDEW Vol. 11, 398-401.
 E. g. Arundel and Brighton, Decision before Jennings, 9th September 1998, MDGBI, Vol. 34, 99-102; Plymouth, Decision before Paver, 19th July 2005, MDGBI, Vol. 41, 167-169.
 E.g. Westminster, Decision before Harrington, 1st October 1998, MDGBI, Vol. 34, 153-156.
 E.g. Plymouth, Decision before Perkins, 23rd March 1999, MDGBI, Vol. 35, 145-151.
 E.g. Southwark, Decision before Hatton-Hall, 30th January 2003, MDGBI, Vol. 39, 185-190.
 E.g. Lancaster, Decision before Tully, 5th December 2002, MDGBI, Vol. 39, 166-170.
 E.g. Liverpool, Decision before Wood, 21st November 2003, MDGBI, Vol. 39, 163-166.
 E.g. [1st Instance] Galway, Decision before Curran, 25th March 1992, MDGBI Vol. 30, 96-98; [2nd Instance] NATI, Decision before Mulcahy, 8th April 1993, MDGBI Vol. 30, 99-100; [3rd Instance] Liverpool, Decision before Daley, 17th August 1994, MDGBI Vol. 30, 101-105.
 E.g. [1st Instance] Dublin, Decision before Herron, 13th December 1989, MDGBI Vol. 34, 102-104; [2nd Instance] NATI, Decision before Corcoran, 2nd September 1993, MDGBI Vol. 34, 105-106; [3rd Instance] Roman Rota, Decision before Stankiewicz, 19th October 1998, MDGBI Vol. 34, 106-115.
 J. O’Neill, “A basic look at lack of due discretion”, CLSN 33, June 1977, 40-44; “Lack of internal freedom as applied to lack of due discretion (a law section from a case heard in Birmingham on appeal from Westminster)”, CLSN 42, September 1979, 27-29; J. Jukes, “Nullity Headings under Canon 1095”, CLSN 77, March 1989, 67-72; Lancaster Tribunal, decision before McArdle, (bulimia (1095 3°)), CLSN 102, June 1995, 41-46; Brentwood Tribunal, decision before Read, (fetishism (1095 2°)), CLSN 102, June 1995, 47-57; Hexham and Newcastle Tribunal, decision before Zielinski, (Klinefelter’s Syndrome (1095 3°)), CLSN 102, June 1995, 58-67; J. Jukes, “Choice of Grounds of Nullity and the evaluation of evidence offered in support of claims of nullity of marriage under Canon 1095 2°”, CLSN 112, December 1997, 53-61; P. Wilson, “Gambling and Nullity of Marriage: A Law Section”, CLSN 112, December 1997, 70-76; P. Gilbert, “Gambling and Nullity of Marriage: Commentary”, CLSN 112, December 1997, 77-79; R. Harrington, “Survivors of Childhood Abuse and their capacity for marriage consent”, CLSN 118, June 1999, 45-59; G. Read, “A recent Rotal decision coram Stankiewicz (25.11.99): commentary”, CLSN 136, December 2003, 24-27; D. Byrne, “Law Section by Defender: Case of Albus and Senitoba (schizophrenia)”, CLSN 136, December 2003, 28-30; D. Byrne, “Law Section by Defender: Case of Henricus and Hilaria (rejection of a handicapped child)”, CLSN 136, December 2003, 31-33; J. Jukes, “Emotional immaturity: Canon 1095 2° and 3°”, CLSN 136, December 2003, 34-37.
 B. McCumiskey, “Inability and its development in Rotal and British-Irish jurisprudential law”, Studia Canonica 16(1982), 279.