Written by Martin Poelman
Published on 13 July 2026
Is the study of law a science or not?
It is sometimes debated whether law is a science. In any case, it is clear that it is not an exact science. One reason for this is the use of open standards. There is not always an unequivocal answer to legal questions and legal practice regularly shows this. Consider eminent legal scholars who, as Procurator General, give an opinion to the Supreme Court after which it decides to go ‘contrair’ and thus deviate from the legal opinion. Or think of Courts of Appeal that set aside judgments of the Courts of First Instance after which the Supreme Court in turn sets aside the judgment of the Court of Appeal. Practice is unruly, which means that it is not always easy to give legal advice. Settlement is therefore often preferable to an all-or-nothing judgment.
TAP case
I still think a good practical example to illustrate the above, is the somewhat older judgment of the EU Court of Justice in a case involving the Portuguese airline TAP (Case C-160/14, Judgement of the Court of 9 September 2015, Case João Filipe Ferreira da Silva e Brito and others v Estado português). The EU Court came to a judgment diametrically opposed to that of the Portuguese Supreme court and even concluded that the Portuguese State was liable, to whom the action of the Portuguese court was imputed. Admittedly, it concerned the always tricky matter of ‘transfer of undertaking’. This matter is regulated by a European directive and, on that basis, incorporated in the legislation of the member states of the European Union (in the Netherlands in Articles 7:662 et seq. of the Dutch Civil Code).
Transfer of undertaking?
In a nutshell, ‘transfer of undertaking’ refers to situations where there is a transfer of (parts of) undertaking A to undertaking B. Employees who were working at (the relevant part of) undertaking A ‘automatically’ become employees of undertaking B. It looks like some kind of slave trade, because the transfer is ‘triggered’ by the selling entrepreneur and not by the desire of the employees in question. But it is well intentioned, namely to protect the employees and not leave them in an empty shell.
First judge says yes
The TAP case involved a Portuguese airline, Air Atlantis SA (“AIA”), which went bankrupt in 1993, resulting in the collective dismissal of its employees. AIA’s main shareholder, TAP, took over part of the flights, part of the equipment, rent for leases and part of the dismissed workers. The workers who had not been selected to join TAP, challenged the collective dismissal in the Tribunal do Trabalho de Lisboa (the Portuguese Court of First Instance), seeking reinstatement within TAP, payment of their wages and damages. The Tribunal do Trabalho partially granted the appeal and ordered TAP to reinstate the workers.
Second court says no
The ruling was appealed to at the Tribunal da Relação de Lisboa (the Portuguese Court of Appeal), which overturned it.
Portuguese Supreme Court also says no
The workers then appealed the latter judgment in cassation to the Supremo Tribunal de Justiça (similar to our Supreme Court), which ruled that the collective dismissal was not unlawful. The consideration was that the ‘mere continuation’ of a commercial activity was not sufficient to constitute a transfer of undertaking, as the identity of the establishment must also be preserved. The Supremo Tribunal ruled, inter alia, that in carrying out the flights in question, TAP did not use an ‘entity’ that had the same identity as the ‘entity’ that previously belonged to AIA. As a result, according to the Supremo Tribunal, there could be no transfer of undertaking.
The obligation to refer questions to the EU Court when in doubt about the interpretation of EU law
Some of the 97 aggrieved workers had asked the Supremo Tribunal to request a preliminary ruling from the EU Court to clarify whether there was a ‘transfer of undertaking’. After all, the Portuguese legal provision is based on an EU Directive. Article 267 of the Treaty on the Functioning of the European Union (TFEU) provides that the Court of Justice of the European Union has jurisdiction, by way of preliminary rulings, to rule on the interpretation of the Treaties, as well as on the validity and interpretation of acts of the institutions, bodies, offices or agencies of the Union. This includes questions of interpretation of an EU directive. Under the same provision, if such a question is raised in a case pending before a national court whose decisions are not appealable under national law (as in the TAP case), that court is obliged to refer to the Court.
Exception if ‘no reasonable doubt can exist’
There only is an exception to the obligation above, if the highest court has found that the question raised is not relevant or ‘that the provision of EU law concerned has already been interpreted by the Court or that the correct application of EU law is so obvious as to leave no scope for any reasonable doubt. ‘ (judgment sub 38). The latter 2 situations are also described as ‘acte éclairé’ and ‘acte claire’ respectively. Clearly, the court must be very sure of its case in such a case.
Portuguese Supreme Court has no doubt
According to the Supremo Tribunal, in the TAP case there was ‘no material doubt’and for that reason no obligation to refer to the EU Court. That in itself was extraordinary, as the first court had come to a different interpretation. You would think that would at least cast doubt on the correct interpretation.
New round, new opportunities: unlawful judgment?
The workers did not leave it at that and subsequently brought an action for civil, non-contractual liability against the Portuguese state, alleging that the Supremo Tribunal’s interpretation of Union law was incorrect and that this court had not complied with the obligation to ask the EU Court the relevant questions on the interpretation of Union law. This second case before the Portuguese court thus (also) involves the question of whether there was an unlawful judgment.
An obstacle to compensation in Portuguese law
In its defence, the Portuguese state argued, among other things, that damages can only be claimed ‘if the decision causing the damage was previously annulled by the competent court’. In other words, since it is a decision of the highest court, no damages can be claimed.
EU Court comes to contrary decision: transfer of undertaking
This time, the competent Portuguese court (‘Varas Cíveis de Lisboa’, the competent civil court in Lisbon at the time) did find that questions had to be put to the EU Court. The EU Court eventually ruled that there was indeed a ‘transfer of undertaking’ within the meaning of the EU Directive. The EU Court also found that the Portuguese Supreme Court was indeed obliged to ask preliminary questions. The reason for this was not only the different interpretations in Portuguese jurisprudence, but also the fact that the interpretation of the concept of ‘transfer of undertaking’ in the EU ‘gave rise to a great deal of uncertainty on the part of many national courts and tribunals which, as a consequence, have found it necessary to make a reference to the Court of Justice’. That uncertainty shows ‘not only that there are difficulties of interpretation, but also that there is a risk of divergences in judicial decisions within the European Union’. (judgement sub 43).
This case shows how differently judges can think about a particular set of facts. But it also shows that some cases can take a very long time. Air Atlantis was dissolved in 1993, but the Court of Justice in Luxembourg did not issue its judgment until 2015, which is 22 years later. This ruling is also interesting in connection with the Court’s opinion on the liability of the Portuguese state. That is the subject of another publication.
