There are two errors in this review. On page 4, the quotation from Barnes should be corrected to read:
‘A Deduction is an ordered pair, <{α1, α2, …, αn}, σ > such that (1) σ follows necessarily from {α1, α2, …, αn}, and (2) σ holds (if it holds) because of each αi.’
The second error is in the third footnote, on page 5, wherein there is an extra word. The pertinent sentence, once revised, should read:
‘They offer us knowledge which we already had under a different mode of presentation but do not straightforwardly lead us to know new things.’