It is a fact known by most that the thought processes of people are typically segregated into two camps: those who are governed primarily by rational, logical thinking, and those who are governed by emotional, reactive processes. It is also evident to anyone who has ever tried to have a discussion or argument with someone who thinks in the opposite way than they themselves do that trying to carry out such an exercise is nigh on impossible: the rationalist will come to the table with reasoned arguments and logical foundations, while the emotionalist will be directed primarily by their feelings. In a hypothetical scenario where both sides are strawmen, the rationalist will be frustrated that the emotionalist cannot see reason, while the emotionalist will be frustrated that the rationalist cannot understand their feelings.
First, it is of paramount importance to understand the nature of argument. Argument is not, as common connotation will have one believe, an inherently bad thing. In fact, a lively discussion between people of opposing viewpoints can have a beneficial effect on both parties, as each side becomes more enlightened to the other's point of view. While such a discussion may not result in a change of either party's opinions, both should be more informed, and from there they can reevaluate their opinions and/or beliefs and reconstruct them in a more educated manner. This is, of course, possible only in a discussion between true rationalists - that is, when both parties are arguing for their arguments' sakes, and not for their own. An argument between emotionalists, however, quickly devolves into a personal battle, where the feelings of the participants become more important than the relevant points of the debate. As soon as an emotionalist feels "offended" and shifts the dialogue to that instead of the true subject of discussion, then the discussion has ended and cannot recover.
What is the primary difference between the two types of arguments outlined above? It is simple: between rationalists, it is possible to make the distinction between disagreement on a neutral idea, and between emotionalists, it is not. If Amy and Brian, two rationalists, hate each other's guts, it is still possible for them to have a reasoned discussion, because they will be able to put aside their personal disdain for each other because that disdain has nothing to do with the topic that they are discussing. In contrast, Charlie and Danielle, two emotionalists who dislike each other, may be able to start out an argument just fine, but inevitably one will say something that the other takes offense to, and the emotional reaction from the offended party will redirect the flow of argument from the neutral topic to the perceived personal attack. In a rational discussion, the optimal outcome is that both parties leave better-informed, and the weaker position is deconstructed, reevaluated, and more strongly reconstructed, possibly with a different conclusion than the weaker form; there is nothing wrong with changing one's opinions or beliefs when presented with evidence or reasoned arguments that are contrary to one's positions. However, in an emotional discussion, the optimal outcome is that a person reaffirms their own position, allowing them to feel superior or "good" about themselves. The problem is clear as day: a rationalist seeks to learn and revise their opinions based on facts, while an emotionalist seeks self-masturbation in spite of facts.
It is clear that the rationalist approach is superior to the emotionalist approach when it comes to discussion. The counter-argument from emotionalists, when presented with this assertion, is without exception that "their opinions are valid too". Herein lays the flaw: opinions are not valid unless backed by a logical foundation. This is easily shown by considering the opposite: what if opinions were, in fact, valid by dint of existing? Then such opinions as "Murder is a fun way to spend a weekend afternoon", "Rape is an acceptable way of indulging my desires", and "Nuclear weapons should be used to commit genocide" would all be "valid". These are opinions based not on facts or reasoned systems of morality, but instead on the feelings of the individual. Kant's categorical imperative states that people should act only in such a way that their action should become a universal law. The most important draw from this is the removal of personal ego from decisions; if a person must act in such a way that everyone must act that way, then selfishness must be discarded in favor of the good of the whole. Taking "action" in its broader definition of not only physical action but mental action, the formulation of opinions should be done only in such a way that selfishness is abandoned in favor of an objective observation of facts.
The conclusion that is seemingly drawn is that emotions and emotional people have no place in arguments or discussions. This is incorrect. The above scenarios outline only the extremes of both ends; it is not truly a dichotomy between rationalism and emotionalism, but rather a sliding scale. An emotional person may be able to have a discussion without devolving to personal attacks and defenses, while a rational person may be overcome by cognitive dissonance when presented with overwhelming evidence contrary to their position and lash out. The optimal position that a person should be in when having a discussion or argument should be one firmly rooted in the rational side, but with a consideration for the emotional consequences of the outcome of the argument. How people attain this balance will differ based on their beginning propensities. A person on the rationalist side of the spectrum must focus on developing empathy, so as to be able to evaluate the emotional effect of their argument and incorporating it with an adequate weight when compared to the rational and factual evaluations. In contrast, an emotionalist must train themselves to segregate their ego from their arguments, training their thought processes to overcome their natural propensity for self-affirmation. Both paths are difficult, though the emotionalist's path is slightly more so. It is not, however, impossible for a person coming from either end of the spectrum to achieve the ideal position of balance that will engender discussions that will result in the most productive and mutually agreeable conclusions.