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tial validity. A closer inspection reveals that the premisses (S 1 to S 4 ) do notprovide sufficient support for the conclusion (C). Stated somewhat differently,on the basis of S 1 to S 4 one would, at best, be able to arrive at the conclusionthat Pretoria has poor drivers — but certainly not that they are the worst in thecountry. While it may be true that they are the worst, this conclusion cannot besubstantiated by the supporting evidence. The important point that we wish tomake is the following: even if it is accepted that the supporting evidence (thepremisses) is true (in this case that s : to S 4 are true), the possibility remains thatit does not constitute sufficient evidence for the conclusion. The problem incases of this nature, is usually that the conclusion is broader than implied bythe premisses. At the same time, our example also illustrates that inferentialvalidity is not associated with the truth or reliability of the premisses (for thesake of the argument it is accepted that they are true), but rather with therelationship between the premisses and the conclusion.We may, therefore, attain inferential validity if:(1) The supporting evidence is relevant to the conclusion, and(2) the supporting evidence offers adequate support for the conclusion.It is usually easy to meet the first condition (the requirement of relevance).Assume that we were to add the following to the premisses in the precedingexample:Free download from www.hsrcpress.ac.zaS 5 :Pretoria is the capital of the Transvaal.Although this statement happens to be true, it is clearly quite irrelevant to theconclusion. If, however, we were to add the following premise to the argument— S 6 : The accident rate in Pretoria is the highest in the country, we wouldhave more relevant supporting evidence. Not only is the statement in S 6relevant, but it also increases the likelihood that the conclusion (to the effectthat Pretoria drivers are the worst in the country) is true. Adding S 6 would beregarded by some people as adequate evidence for the acceptance of theconclusion (The second condition of adequate support). In the final case, theinclusion of S 6 could mean that the argument as a whole complies with therequirement of inferential validity. The supporting evidence (S 1 to S 4 and S 6 )could then be regarded as providing both relevant and sufficient evidence insupport of the conclusion. To explicate the notion of sufficient evidence morethoroughly, we shall discuss an example which has been taken from LarryWright’s Better reasoning. The example also illustrates the fact that gradationsmay exist in the relationship between premisses and conclusion. In otherwords, specific evidence may support a conclusion to a greater or lesserdegree.108