blasphemy : one cannot without committing sin, have the desire -- I would blaspheme God if it were not wrong; the condition is an impossible one and therefore does not affect the desire itself. and therefore it is not necessary that the definition of sin in general should be verified except in that sin in which the nature of the genus is found perfectly. Actual personal sin is voluntary by a proper act of the will.The pleasure taken in a sinful thought ( delectatio, gaudium ) is, generally speaking, a sin of the same kind and gravity as the action which is thought of. The definition of sin may be verified in other sins in a certain sense" (St. Original sin is voluntary not by a personal voluntary act of ours, but by an act of the will of Adam.According to the nature of the perfection which it limits, evil is metaphysical, physical, or moral.Metaphysical evil is not evil properly so called; it is but the negation of a greater good, or the limitation of finite beings by other finite beings.
As regards the principle from which it proceeds sin is original or actual.If, on the other hand, the condition does not remove the sinfulness of the action, the desire is also sinful. It is to be noted that "sin" is not predicated univocally of all kinds of sin. Actual sin primarily consists in a voluntary act repugnant to the order of right reason. The division of sin into original and actual, mortal and venial, is not a division of genus into species because sin has not the same signification when applied to original and personal sin, mortal and venial.This is clearly the case where the action is intrinsically and absolutely evil, e.g. "The division of sin into venial and mortal is not a division of genus into species which participate equally the nature of the genus, but the division of an analogue into things of which it is predicated primarily and secondarily" (St. "Sin is not predicated univocally of all kinds of sin, but primarily of actual mortal sin ... The act passes, but the soul of the sinner remains stained, deprived of grace, in a state of sin, until the disturbance of order has been restored by penance. Mortal sin cuts us off entirely from our true last end; venial sin only impedes us in its attainment.It is divided into sins of commission and omission.A sin of commission is a positive act contrary to some prohibitory precept; a sin of omission is a failure to do what is commanded.