necessary and sufficient in all cases to constitute grave matter, and the relative sum, which will be sufficient for grave matter, regard being had to the loss of the owner. The general principle on which the quantity required for grave sins depends is the damage caused by the theft. For it is a grave sin to cause grave damage without a just reason; but in the case of very rich persons or companies we must consider not only the personal and particular damage done to them by theft of what belongs to them, but also the harm done to society. It may well be that a rich millionaire would not be appreciably worse off for the loss of a hundred pounds or of ten times that sum. The damage done to him by a thief taking a hundred pounds would be relatively less than if sixpence were taken from a day labourer. However, we must also consider the harm done by theft to the community and to the security of property. The malice of sin is not measured merely by the harm done to the individual; the harm done to society and other considerations also enter into the estimate. We must, then, besides considering the damage done to the owner of stolen money, weigh also the harm which theft does to society. And if grave harm is caused to society by stealing a certain sum of money, if the security of property would be seriously imperilled unless the theft of a certain sum were forbidden under pain of mortal sin, that sum will be the absolute quantity required for a mortal sin of theft. What the precise sum is must be left to the judgement of experts, who will consider all the circumstances of time and place, for, as values are perpetually changing, the sum required for a mortal sin of theft will also change. Under present circumstances, in civilized countries where similar conditions of commerce prevail, the common opinion of theologians fixes one pound sterling as the absolute sum required for a grave sin of theft. This will serve, therefore, as a measure of the gravity of theft from very rich people, or from companies with large resources.
However, a mortal sin of theft may be committed by stealing a much less sum than one pound if the theft cause great harm to the owner of what is stolen. The loss of a day's wage or of a sum which is sufficient for the support of a labourer and his family for a day, is a serious loss for a workman, and so, as the common opinion holds, the theft of such a sum from a labouring man is a grave sin. Something between this and the absolute sum will be grave matter if stolen from persons whose wealth is between the two extremes.
Matter which in itself is grave may become light on account