It has been said in popular culture “if it feels good, do it.” In the case of BPD, the saying should be more like “if I feel it, it must be true.” Emotional reasoning is the inclination to believe that feelings actually equal (or cause) facts and events to happen. The feelings of someone with BPD are so immediate and overpowering; it is difficult for someone experiencing these feelings and emotions to believe that these feelings are self-generated. It is important to remember the function of emotions to understand why emotional reasoning takes place. As stated, the basic emotions function to detect threats to one’s survival (or either body or mind). Fear is useful to protect a person from attack. Anger is useful to cut a threat off and attack back quickly and decisively. However, in the case of BPD, a person will react to threats that are not completely “true.” Although she may feel that a situation is threatening, it is possible that she is detecting a threat that doesn’t actually exist.
My wife had a sure-fire defense: ‘You’re cornering me.’ But while I thought I was ‘cornering’ her into admitting the truth, she felt I was manipulating her into feeling something about herself other than what she felt. – ATSTP member A. (male, divorced)
In the case of A’s wife above, she detected a threat from him – that of “cornering” her – and would react with fear and anger. He didn’t notice that she felt the threat because his intentions were not threatening. His intentions were merely to have his wife admit the “truth.”
The problem with “the truth” when emotions are involved is that emotions lead to emotional reasoning and when someone is subject to emotional reasoning the only “truth” is how she feels. She will seek to mold the “facts” of a particular situation to match her feelings. This emotional reasoning is natural for BP’s. As Ekman states in Emotions Revealed:
For a while we are in a refractory state, during which time our thinking cannot incorporate information that does not fit, maintain or justify the emotion that we are feeling.
This is an important piece of information, which is why I re-quoted it here. He states “our thinking cannot incorporate information that does not fit, maintain or justify the emotion that we are feeling.” During a period of emotional dysregulation, the person with BPD will be unable to “see the facts” if those facts do not support the conclusion of what she is feeling. Therefore, the person with BPD is likely to interpret or generate alternative “facts” that support what she is feeling. She cannot be “reasoned with” during this state because reasoning requires an objective view of the evidence presented. The strong (usually negative) feelings will drown out all reasoning or examination of evidence.
This aspect of BPD is one of the more frustrating ones for loved ones. Loved ones (especially partners) will often ask, “When will this person admit to the truth?” I have already covered lying previously, so I will not expound on the nature of truth. Instead I will only say that emotional reasoning is born from strong emotional reactions, whether or not these emotions are based in reality – whether or not the threat is real or imagined.
From When Hope is Not Enough FAQ Section.