hello -
I’m not so sure.
In the first sentence, change in one of the determinants does not necessarily mean overall change will occur.
For example, under certain circumstances, one can swap the legs around without making a difference in the stool being level.
Additionally, circumstances as Hardon refers to them are secondary properties of a moral act - so they as it were make more or less obvious the moral goodness or evil of an act, something perhaps akin to the height of all of the legs.
So the example of a stool seems like an accurate analogy, but falls short when we start to try to unravel what Hardon is saying.
Yes, it is not a perfect analogy. I simply came up with it to illustrate that in a system of several parts “relative” needs a better definition. I agree that circumstance is not like the other two determinants.
circumstances as Hardon refers to them are secondary properties of a moral act
But Hardon does mention also that "[some] circumstances so affect the morality of an action as to change its species". He gives two examples: one when the character of an immoral act changes with circumstance -- theft becomes sacrilege, etc., and the other when the degree of goodness or badness changes. But can circumstance change the bad into good or vice versa? This is not among the examples he gives, but I can recall this story that actually happened to some friends of mine a while back.
A group of college kids go out camping and drinking in the mountains. At night one of them, still drunk, walks out of the tent and accidentally walks off the cliff, suffering a serious injury. His buddies recover his body, still alive. Now they have a moral dilemma: no one is sober yet a life can be saved if the victim were taken to the hospital (it was in the age before cell phones in a sparcely populated country). So one of them decided to drive drunk (as it happened, the victim died in the car).
Here we have, arguably, a case when an intrinsically immoral object, drunk driving, is combined with a noble end, to deliver a victim to the hospital, and the circumstance of no sober driver being available.
It seems that here the circumstance, and not any other determinant, is deciding in favor of the act. Indeed, if there was a sober driver in the party, yet a drunk man insisted on driving (for example, because he was a close friend of the victim, or was the car owner), the drunk driving becomes unexcusable.