Having completed his powerful arguments in favor of self-introspection, in chapter three Luzzatto begins teaching us how it is to be done - and here he makes a terrifying statement. He writes that we cannot be satisfied by merely identifying what it is that we are doing wrong. We must also investigate the things that we think we are doing right.
The materialism and physicality of this world is the darkness of night for the mind's eye and causes... errors in our perception to the point that we view evil as if it is really good.
Well, if our moral compass is broken, how can there possibly be any hope for us to identify and fix what's wrong?!
*UPDATE*
I return now to this question two and half years later (Jan 2, 2014) for I believe I have found the answer. "Found" isn't the right word of course, for it was right there the whole time. In fact, I think we may have just hit on the central point of the entire chapter.
The source Luzzatto cites which advocates introspection is the Gemora in Baba Batra (78b):
על כן יאמרו המשלים באו חשבון (במדבר כא:כז), ע"כ יאמרו המושלים ביצרם בואו ונחשב חשבונו של עולם, הפסד מצוה כנגד שכרה, ושכר עברה כנגד הפסדה
Those who have conquered their Yetzer [HaRa] advise, "Come and make the reckoning of existence, the cons of a Mitzvah vs. its pros, the pros of an Aveira vs. its cons."
Note that the recommended introspection does not ask us to evaluate the rightness or wrongness of a given behavior. As Luzzatto pointed out, this is beyond us. Our moral sense is blinded by materialism and we cannot be trusted to identify good and evil. Rather, we should weigh the pros and cons. Make a chart. Consider the advantages and disadvantages. Ask yourself if it is really worth it. The wisdom of this advice is that it sidesteps the morality question and forces us to subject our passions to the cold analysis of rational thought. Oftentimes, this alone can have the effect of wet blanket on the fire of desire.
In a nutshell, forget good and evil and forget right and wrong. Think about it and you'll realize it's just not worth it!
*UPDATE II*
I return once again to this question (almost a year later, Nov. 27, 2014) with a new insight.
I realize now that I was reading the advice of "those who have conquered their Yeitzer" (the Moshlim) as a solution. Do a critical introspection, a Cheshbon HaNefesh, and then, presto - problem solved - you will be a Zahir. This is inaccurate.
Their advice is not a solution; it is a process.
The Ramchal described the problem with the Yeitzer. It is not just that it drives me to sin; it also corrupts my thinking. As a result, I cannot trust my judgement. So here is the advice. Make a cheshbon. Identify something, anything, even just one single little thing, that you want to eliminate from your behavior. Come up with a strategy. And then, for once in your life, overpower your negative drives, put your rational mind into the driver seat and do what you chose to do.
Here's the kicker: it does not matter if you are wrong! The point is that you decided to change your behavior - and you did. This exercise alone is a victory of mind over Yeitzer. No longer are you a blind man at the river's edge or a horse galloping through life unthinkingly. You thought, you decided, and you acted. You have taken the first step towards becoming a Moshel.
It is a process.
The more you make a cheshbon and follow through, the more you become a Moshel.
The more you become a Moshel, the more you loosen the Yeitzer's grip on your mind.
The freer you are of the Yeitzer, the clearer your vision becomes and the more accurate your sense of right and wrong.
And the more accurate your sense of right and wrong, the more Zahir you can be.
*UPDATE III* August, 2017
This insight gives us a new way to understand a familiar Talmudic teaching: "If this low life (the yertzer hara) confronts you, drag him to the Beis Medrash." This is typically interpreted in light of a different familiar teaching: "I created the yetzer hara and I created the Torah as an elixir." Torah study is the antidote to temptation, and so the sages advise that when the yetzer hara tempts you with sin, "drag him to the Beis Medrash." Sit down and learn Torah and all desires will dissipate.
There are two problems with this interpretation. The first is textual. If the Talmud wants to advocate Torah study as the antidote to the yetzer hara, then it should speak straight and say, עסוק בתורה, "toil in Torah." But it doesn't say that. Instead, it tells us to bring the yetzer hara into the Beis Medrash. What does that even mean? Shouldn't we leave the yetzer hara at the door? Why defile sacred space with evil?!
The second problem is that there are times and places where learning Torah is just not an option. For example, Torah study is strictly prohibited in areas where there is a foul odor. This includes bathrooms, bathhouses and tanneries. When a farmer fertilizes his field he may not learn. In such situations, what should a person do if he is confronted by the yetzer hara? Moreover, learning disabilities and ADHD make Torah study exceeding difficult for some Jews. What are they to do when they are confronted by the yetzer hara?
In light of the efficacy of cheshbon to undermine the yetzer hara, we can offer an alternative reading of the Talmud's advice. If the yetzer hara confronts you, drag him into a virtual Beis Medrash, sit him down and make him your chavrusa. Challenge him, question him, interrogate him. This conversation with the yetzer can be conducted anywhere, even inside a bathroom, and by anyone, no matter what their IQ. Under the bright lights of the "Beis Medrash" - simple questions and rational analysis - the yetzer hara shrivels up and dies.
Ultimately, the reason this method is so effective is not merely because passion is irrational, but because this line of questioning is essentially a quest for righteousness. As such, it is Mussar and thus a form of Torah, and as Rabbi Pinchas ben Yoir taught, Torah leads to Zehirus. To use Luzzatto's metaphor, Torah functions as the sole antibiotic for the bacteria of desire. Although Torah study is prohibited in the presence of an odor, nonetheless, we have no alternative other than to defend ourselves and defeat the yetzer hara in the foul dark places where he lurks.
