Those queries link to some old posts of mine that summarized some psychological research regarding how Jewish and Christian persons differ in how they moralize mental states and how that research prompted some of my own students to investigate the snarly issue of "sinning in your heart."
Remember the famous 1976 Playboy interview with Jimmy Carter? In that interview Carter caused some controversy by confessing that he had "lusted after women in my heart many times."
Most Christians would sympathize with President Carter as many Christians believe that you can "sin in your heart," that thoughts have moral status. This belief is largely drawn from the Sermon on the Mount:
Matthew 5.21-22, 27-28This phenomena of "sinning in your heart" is illuminated by an interesting study conducted by psychologists Adam Cohen and Paul Rozin (Cohen & Rozin, 2001. "Religion and the morality of mentality." JPSP, 81, 697-710).
"You have heard that it was said to the people long ago, 'Do not murder, and anyone who murders will be subject to judgment.' But I tell you that anyone who is angry with his brother ]will be subject to judgment."
"You have heard that it was said, 'Do not commit adultery.' But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart."
In this study, Cohen and Rozin compared Jewish and Christian participants on the degree to which they moralize mental events. In the study, Cohen and Rozin found that Jewish participants did not moralize mental events. Only choices leading to behaviors appeared to have moral status (i.e., be designated "right" versus "wrong").
By contrast, Christian participants did moralize mental events. That is, even if a person made proper moral choices and acted in an ethical manner they could still "sin in their hearts," and, as a result, be a "bad" person.
Why this difference in how mental events are or are not moralized?
One answer is that the rabbinic tradition posits a different moral psychology than what most Christians subscribe to. Specifically, the Jewish rabbis have distinguished between two fundamental human inclinations which clash in the human psyche. There is an evil impulse, the "yezer ha-ra," which struggles against our good impulse, the "yezer ha-tov." Psychologists call this kind of theory a "folk psychology," a psychological theory about how the mind functions that is culturally posited or phenomenologically derived. Most cultures have a "folk psychology," common assumptions about how the mind works.
What is interesting is that this rabbinic folk psychology, positing an internal conflict between the yezer ha-ra and the yezer ha-tov, creates a situation where mental events are not moralized as was observed by Cohen and Rozin. How so? Well, given the constant presence of the evil impulse, the yezer ha-ra, thoughts of lust or hate or envy are, in principle, present in all moral choices. Thus, it is no "sin" to have such thoughts. It is just a part of human psychology (from the Jewish perspective). A person cannot rid themselves of the yezer-ha ra, one can only choose not to obey it. And, thus, it is the choice that has moral status, not the thoughts of the yezer ha-ra.
By contrast, Christians don't have a folk psychology to help them sort out how any given thought is a temptation versus a sin. For Jewish persons the situation is straightforward, all thoughts are temptations, only behaviors have moral status. Christians, by contrast, believing they can sin in their hearts, can't rely on a behavior/thought distinction. Christians have to sort between the thoughts themselves. Which is tougher to do and creates a lot of neurotic, paranoid, and confused Christians.
When does a thought become a sin?
Many years ago some of my students investigated this question.
Specifically, these students asked, How might a typical Christian decide when a particular thought becomes a sin?
For example, let's say, borrowing a stimulus from Cohen and Rozin's study, a married man works with a sexually attractive co-worker. Due to her attractiveness he finds, fairly regularly, sexual thoughts drifting through his mind. Is this man, per Jimmy Carter, committing infidelity in his heart?
Maybe, but we'd like some more details. What do we mean by "sexual thoughts"? And when might such thoughts move from temptation to sin?
My students came up with two related ideas that might be guiding how Christians judge these questions for themselves.
First, maybe a thought becomes a sin if the thought starts moving toward "obsession." That is, if the man in the example above thought about having sex with this co-worker for much of the day Christians would be increasingly likely to label those thoughts as sin.
Second, maybe it is not the amount of thought that matters but how the person responds to and resists the thoughts. Going back to the example, when the sexual thought emerges does the man try to shoo the thought away? Or does he entertain the thought, allowing it to sit in his mind for a time?
Clearly, these two things are correlated--degree of contemplation and resistance to the thought--but they are distinct features. That is, although resisting "tempting" thoughts should reduce their frequency, there are many cases where there is both high thought frequency and resistance. The struggling addict comes to mind.
To test how these dynamics might affect judgments of "sinning in your heart," my students borrowed the experimental protocol of Cohen and Rozin and tweaked it to manipulate the degree of contemplation and resistance displayed by the people described in the scenarios (like the one discussed above). And among a group of Christian participants my students found that assessments of sinfulness were based upon degree of resistance. No effect was found for degree of contemplation.
What these results suggest is that, at least for the sample we studied, Christians appear to view "sinning in your heart" as a sin of omission rather than one of comission.
Specifically, a lustful or hateful thought can erupt in your mind at any time. Further, these can even be very frequent thoughts. But that, according to our research, doesn't make the thought a sin. What is critical, morally speaking, is what happens next. If what happens next is a cognitive attempt to shut down the thought, then the thought is judged to be a temptation and not a sin. And you might be tempted a lot, over and over. But if you keep shutting down or fighting the thought that's okay.
But if, however, the thought is entertained, courted, and elaborated the mental events are increasing judged as being sinful, examples of lust, envy and hate.
Summarizing the findings, the sin isn't in the experience, even the frequent experience, of the thought--a sin of comission. Sinning in your heart is a sin of omission, failing to "do battle" with the thoughts, no matter how frequently or infrequently they occur.
This, at least in the sample we studied, is a part of the "folk psychology" guiding how Christians judge thoughts as being temptations versus sins.