Celebrating attitudes such as דן כל אדם בכף זכות (Dan kol adam b’kaf zechut), “consider everyone to be worthy”, i.e. the presumption of innocence, as “evidence” of Judaism’s inherent idealism and liberalism only discloses one’s total lack of understanding and context. Likewise, our total acceptance of one who does tshuvah is not based on wishful thinking or pollyana-ism, but rather it reflects a very deep Torah-based truth.
Raish Lakish, in Gemara Sota 3a, ריש לקיש אמר: אין אדם עובר עבירה אא”כ נכנס בו רוח שטות, teaches that a Jew sins only when his spirit, רוח (ruach) is invaded with שטות (shtut) folly of stupidity. This implies that what we assume to be “common sense” among our people prevents sin. Of course, this “common sense” is the awareness that among the infinite list of God’s ‘activities’ is monitoring our every action and presenting us with its consequences. In other words, the ‘folly of stupidity’ that enables sin is thinking you can get away with it, not some sort of ‘inherent good instincts’ we might enjoy as an accident of genetics.
תשובה (Tshuvah), badly translated as “repentance”, but, as we can see now means a “return” to our senses, goes far beyond admission of sin and resolve to change–although they are certainly necessary elements to perform tshuvah. Rather, it’s a return to our “natural” realization that we’re not going to “slip a fast one past The Creator”, but, rather, are certain to be caught out and punished. This is called deterrence. It’s also one aspect of what we call יראת ה׳ (Yirat HaShem), the fear of God.
When we look at our own tradition through the lenses of a culture that first developed in hatred for and opposition to our tradition, labeling The Creator as the “Old Testament God of Vengeance”, we lose the point of swift and certain punishment and become ashamed of it. Of course, swift punishment can be motivated by revenge–not an action we’re authorized for by Torah— but eliminating all punishment also eliminates deterrence. This means that there is no longer any disincentive for the strong to exploit-at-will the weak.
The world of halacha also reflects this insight into human nature. Although not accepted by all, Rav Moshe Feinstein‘s famous ruling to allow חלב סתם (chalav stam), ‘regular milk’, issued in 1954, is based on the concept that the deterrences of violating USDA regulations (which include insuring that milk, unless clearly marked on the label, must be only cows’ milk,) are much more severe (fines along with completely closing down the plant) than from violating kosher supervision (i.e., losing only that tiny segment of the market that is kosher-observant). Sure, it’s nice to trust, but since all people are prone to taking advantage if they think they can get away with things, deterrence, whether in the hands of secular authorities or God Himself, is a necessary element.
This is why we can accept a Jew’s tshuvah while not necessarily relying on a mere statement of contrition, either from a non-Jew or a Jew. (Of course, everyone can undergo ‘rehabilitation’ and not only Jews can be relied upon, although I have my doubts with atheists, no matter how much they proclaim some sort of ‘humanist ethics’.) As the Psalm (111:10) says, ראשית חכמה יראת ה׳ (Reishit Chachma Yirat HaShem), The beginning of wisdom is awareness (including fear–יראה, “Yirah” encompasses both awareness/seeing and fear) of God. The Tur expands on this idea in his very first halacha (Orach Chayim 1:1) informing us to begin each day with this realization. As the cliché goes, “Trust…..but verify”.
Thus we’re enabled to dan kol adam b’kaf zechut, relying on the assumption that they are motivated by the exact same deterrence that we are. It’s not racial, nor is it genetic. Rather, it’s a cultural consensus of values based on the knowledge that God, indeed, exists and that He pays attention.