Dutton - Medical Malpractice in SA

Causation 63
Conversely, though, the standard of proving the causal link on a balance of probabilities
must be met; 20 such link cannot be assessed by speculating where, for
example, medical evidence is deficient. 21
5.2.4 The differing standards of proof in regard to causation and damages
Different approaches are adopted to establishing causation and future damages.
The causal connection between damages and the defendant’s act or omission
must be established on a balance of probabilities. 22 In the quantification of
future damages, by contrast, exact calculations are often impossible, and speculation
is thus inevitable. 23
5.2.5 Objective or subjective assessment
A question which in certain circumstances arises is whether the hypothetical positive
conduct to be inserted in the case of an omission must be objectively or subjectively
assessed; in other words, whether the court assesses what the reasonable
person would have done, or what the particular person whose conduct is being
assessed would have done? This arises in particular when the courts evaluate the
20
See generally regarding the approach taken by the courts: Minister of Finance v Gore 2007 (1)
SA 111 (SCA), where the Supreme Court of Appeal held: ‘With reference to the onus resting
on plaintiff, it is sometimes said that the prospect of avoiding the damages through the
hypothetical elimination of the wrongful conduct must be more than 50%. This is often
followed by the criticism that the resulting all-or-nothing effect of the approach is unsatisfactory
and unfair. A plaintiff who can establish a 51% chance, so it is said, gets everything,
while a 49% prospect results in total failure. This, however, is not how the process of legal
reasoning works. The legal mind enquires: What is more likely? The issue is one of persuasion,
which is ill-reflected in formulaic quantification. The question of percentages does not
arise (see to this effect Baroness Hale in Gregg v Scott [2005] 4 All ER 812 HL at para 202).
Application of the “but for” test is not based on mathematics, pure science or philosophy. It
is a matter of common sense, based on the practical way in which the ordinary person’s mind
works against the background of everyday-life experiences.’ (The reference to Gregg v Scott in
Minister of Finance v Gore is of interest, as it refers to a controversial medical malpractice decision
of the House of Lords. The case dealt with the challenging doctrine of so-called ‘loss of
a chance’, which is discussed at para 5.3 below).
21
Minister van Veiligheid en Sekuriteit v Geldenhuys 2004 (1) SA 515 (SCA) at para 41.
22
Minister van Veiligheid en Sekuriteit v Geldenhuys 2004 (1) SA 515 (SCA). Inherent in this process
of hypothetical examination is considerable scope for speculation: Minister of Safety and
Security v Van Duivenboden 2002 (6) SA 431 (SCA) at para [25]. Alston and Another v Marine
and Trade Insurance Co. Ltd 1964 (4) SA 112 (W). This distinction was summarised in the wellknown
words of Lord Diplock in Mallett v McMonagle [1970] AC 166 at 176: ‘The role of the
court in making an assessment of damages which depends upon its view as to what will be
and what would have been is to be contrasted with its ordinary function in civil actions of
determining what was. In determining what did happen in the past a court decides on the
balance of probabilities. Anything that is more probable than not it treats as certain. But in
assessing damages which depend upon its view as to what will happen in the future or would
have happened in the future if something had not happened in the past, the court must make
an estimate as to what are the chances that a particular thing will or would have happened
and reflect those chances, whether they are more or less than even, in the amount of damages
it awards’.
23
The question of compensation for the ‘loss of a chance’ raises similar issues. But see Lord
Nicholls’ questioning of the validity of this distinction in Gregg v Scott [2005] 4 All ER 812 HL
at para [9].