The Assumption of Rationality

The Assumption of Rationality

In the courtroom, judges assume that jurors can and will rely on reason rather than intuition to justify their verdict judgments. As a rule, jurors are asked if they can put aside biases related to experience, belief and opinion and judge a case solely (and rationally) on the evidence at trial.


This judicial assumption appears to be based on an ideology that probably has its roots in 17th century Enlightenment thinking, which proposed that knowledge about reality can be obtained by reason alone without recourse to experience. This is a school of thought associated with René Descartes, among others, which proposed that knowledge and truth can be ascertained by rational thought, and not by divine or supernatural revelation.


In other words, rationalism developed in part as a response to religious dogma, and not so much on the complexity of human motivation.


The assumption that jurors will decide litigation rationally ends up being the 10,000 pound elephant sitting in the middle of the courtroom. It is an elephant that the judge often pretends not to see, a blindness based on long precedent.


For example when an objection to blurted inadmissible evidence is sustained, a judge will admonish the jurors to ignore it. On the other hand, if a juror researched the same information on the internet, it could result in a mistrial.


This G.J. Culkins cartoon speaks to the feeling that many attorneys have in the face of court rulings that ignore the complexity of human behavior.



During voir dire, as long as a juror does not have conscious awareness that experience, belief or opinion will undermine rationality, he or she will be permitted to remain as a prospective juror.


In psychotherapy, a delusion system agreed upon by two (or more) people is referred to as "folie à deux." Folie à deux (or shared psychosis) is a psychiatric syndrome in which symptoms of a delusional belief are transmitted from one individual to another.


In Annie Hall, Woody Allen tells a joke of a man who goes to a psychiatrist and says, "My brother is crazy, he thinks he's a chicken." The psychiatrist says, "Why don't you bring him in?" The man says, "We can't do that; we need the eggs."


Folie à deux is a variation on the psychological defense of denial.


The assumption that rational choice will prevail tends to minimize the complexity of the biological, psychological and sociological roots of human motivations. Attorneys understand that jurors cannot, do not and will not think or behave rationally. In a sentence, this is the raison d'être for my field of trial consulting.