What I want is the truth. What I want is knowledge, not opinion: έπιστήμη, scientia. That which necessarily is, what cannot not-be. If it turns out that the good can be known only by faith, so be it; but I want to know that it can be known only by faith. Till then, I will hone my powers of thought and relentlessly scrutinize any possibility.
Several candidates appear for the title 'good': existence, pleasure, that which we choose for the sake of itself, and flourishing; i.e., the development and exercise of a being's capabilities. That last definition is my own. I still like it, because I am overly fond of my own opinions, but a friend criticized it soundly on the following grounds: development of a being's capabilities reduces to the exercise of a being's capabilities; since everything a being does is an exercise of its capabilities, therefore no matter what it does it is accomplishing the good. Therefore the definition is worthless, in the sense that understanding the good should enable us to set an aim or purpose for our actions, or at least understanding our actions.
Second, existence. Aquinas makes a case for this when he equates the good with being (he also identifies it with the fullness of being. The two statements may or may not be equivalent). This seems to fail for most of the reasons above. If not, consider: every choice and every action is made by an existing being. They are made real, incarnate, by that being. Therefore insofar as they equally exist, they are all equally good, and no choice or way of life could be set above or apart from another as superior or degenerate, even when they completely contradict one another, as they often and manifestly do.
Third, pleasure. This is almost the most attractive of all positions for me, not least because for a Christian (and I know hints of this by experience), true ecstasy is found in the contemplation of and being caught up in the triune life of God. It's also the hardest to refute, because my counterargument is simply this: people find pleasure in cruelty. Torturers, rapists, serial killers, Jane Austen protagonists. Or even on a more mundane level, the sorts of controlling, domineering people who enjoy flaunting their superiority or privilege. I know or have encountered plenty of such people. Lucretius bears witness to this type in general when he writes how sweet and pleasant it is to lie on the grass, watching while a ship wrecks itself on the coast, thinking to yourself how nice it is that you are spared such things. The very definition of Fridge Horror.
Or a second counterargument, addiction: intoxication, food, and sex are all pleasurable; so why is what we call addiction to these things bad?
To the second argument, I would say these ways of life are not genuinely pleasant. Consider gluttony and pornography. Before, mostly during, and after, there is nothing but pain: shame, guilt, self-disgust, self-loathing, seeking to forget, trying to numb, etc. I do not struggle with alcoholism or drug addiction, but I imagine similar patterns are operative.
I regard the answer to the second counterargument sufficient for me, but I don't regard it as demonstrative, because I don't see how it is yet (obviously if anyone does, please tell me). The first counterargument I have much more trouble with. The only possible ways out would be deny a rapist takes pleasure in rape (which seems absurd - granted, I don't struggle with rapacious tendencies myself, but the idea of a woman screaming and crying while I have my way seems anything but fun; on the other hand, rape seems to be most of all about domination and control, and those things certainly are very pleasant. Therefore etc.), or argue that such things are driven by compulsion, and that compulsion is not pleasant. Both of those seem to fail for manifestly obvious reasons.
A way out might be Aristotle's definition: That which we choose for the sake of itself, and not for anything else. Sure, but what is that? Well, he's going to tell us: Happiness. Alright, but what is happiness? And so we return full circle. Because some will say wealth, honor, pleasure, contemplation, etc. Aristotle's own answer seems to be pleasure, understood as contemplation, the highest pleasure.
Aristotle (and Plato, who seems to have a similar view) can hold this opinion because they were conversant in bodily, spirited, and intellectual forms of pleasure, and being deeply experienced in all three (they were all rich Athenian noblemen, and I can only imagine the parties they attended, not to mention enjoying wealth, honors, privilege, and staggering intellectual genius), chose philosophic contemplation as the most pleasant.
That method - an ascent from the lowest, bestial sorts of pleasures to the highest, culminating, in the Christian view of being caught up in divine love and sharing in the love of others - might be a way forward, but I still don't have an objection that demonstrably rejects those lower pleasures as bad while holding pleasure as that which we choose for the sake of itself and not for the sake of anything else.
And there I remain.
Stuck.