Sep 15, 2014 | By

What does it mean to be “rational”?

This would seem to be an easy question. We all agree human beings can be, and should be, rational. But language and discourse about human thought is notoriously slippery. What being rational means has confounded philosophers for thousands of years. [1]

There seems to be agreement that being “rational” is about making decisions. The “ratio” part suggests a parsing – a measuring and choosing of options. If we are choosing between options to make a decision, then the process must be directed towards a goal or set of outcomes.   What do we hope to accomplish by making the decision? In fact, one common definition of “rational” has been – the making of choices to achieve optimal outcomes.


At the same time, a rational decision is one that is based on facts and information. There are deep disagreements about the admissible range of facts and information (can it include emotions, feelings, hunches, the testimony of others, or revelation and spiritual experience, for example), but there seems to be agreement that the factors behind a rational decision need to be accessible to the conscious mind. Randomness or accident is not “rational”; nor are hidden impulses, which are more appropriately labeled as “biases” that can distort rational decision-making.

Rational decision-making, then, involves a process that takes information, identifies desired outcomes, and yields a decision. That process is most often called “reasoning” – following logical rules and using all available information to determine the choice that optimizes the desirable outcomes.[2] Judging whether someone is rational would then depend on answering these questions:

  • Is all available information being utilized?
  • Is the desired outcome being achieved (or likely to be achieved)?
  • Is the line of reasoning logical?

Leaving aside the first two criteria as topics for another time, let’s consider the third. What does it mean for reasoning to be logical? From an academic standpoint, the answer can get mired in technicalities, but for most people, most of the time, one would have to say that being consistent is the most important feature of logical reasoning, e.g. contradictions must be avoided. It is not logical, or rational, for someone to accept or think two opposite and irreconcilable things at the same time. For example, it is not rational to hold as a goal the idea that you can eat your cake and have it too! It is not rational to presume that you can see what is in front of you if you are walking backwards. It is not rational to hold that something is true and false at the same time.   It is not rational to conclude that the apple will not fall if you believe in the law of gravity.

This clarity in the definition of rationality is reassuring, as it seems to provide at least one unassailable basis for judging the quality of our reasoning, or for disputing the rationality of arguments that we exposed to. Most of the time, that is going to be the case.  Next week, however, I will talk about some of the problems that we may find in trying to apply this criteria to the most logical of fields of inquiry – mathematics and physics.

In following weeks I will circle back to some of the questions about information and goals.  Throughout, I hope to keep the exposition as rational as possible.


[1] Sometimes, the etymology of a word can help, but in this case many words (according to Wikipedia) including rationality, reason, and logic all derive from the Greek “logos” which could mean “grounds, plea, opinion, expectation, word, speech, account or reason” – and even logos and its companion “lexis” derive from the same verb ”lego” meaning “to count, tell, say, speak.”

[2] Ironically, this brings us back to another word – reason – that also derives from the Greek “logos”.

7 Responses to “What does it mean to be “rational”?”

  1. […] For an extensive monograph on Rationality, see: Journal (articles are listed in reverse chronological order, the first chapter is here: What Does it Mean to be Rational? […]

  2. […] our discussion of rationality, we began (September 15) by reviewing the three elements of rational decision making: reliance on evidence, focus on […]

  3. […] the first post on rationality (September 15, 2014), I mentioned the controversy over whether emotions, among other things, could be part of being […]

  4. […] week (September 15, 2014) we established a framework for being “rational”, and talked about the importance of […]

  5. George, do I perceive the beginnings of a book? Such an important topic! How often do we read about subjects like rationality in the Writings and don’t take the time (or energy) to admit that we really don’t have much of an understanding of the topic. Of course when a term is used repeatedly we can begin to get the gist of it but still I think your discussion here is of tremendous interest and value. You make some really excellent points about the intrinsic relationship between emotion and rationality, and that makes sense when one realizes the intimate connection between the will and understanding. Is it rational to go out to have breakfast with your friends in a raging snow storm? Well, if one is dying of boredom or loneliness it would I suppose be rational. Maybe “rational” sometimes falls out on a continuum of probabilities…hmmm, a vector quantity with desire on the ordinate and outcomes on the abscissa? A graph of risk and reward? Well, you are the mathematician/philosopher, is this a stretch? I must admit you did initially state that you were starting out morally neutral and I made some observations that strayed from that position. More than enough material for a book…looking forward to your further posts!

  6. George, your topic of “rationality” is is one of those wonderful, and useful, topics that is truly treelike, with many roots in the works of philosophers both present and past, and the ability to branch out, both in our own thinking, and in discourse with one another, with ever finer abstractions.

    My daughter-in-law authored a nice paper, while a student at Berkley, debating whether emotions are rational. It was a little deep for me but it has occurred to me that the root word “ratio” may be an important clue to at least one meaning of “rational”, in that when making a decision, either to act or to accept the truth of something, we need to weigh the “what if”, the theoretical, the raw thought, the supposition on the right side of the equation against the tried and true, the axiomatic, the obvious, on the left side.

    “There seems to be agreement that being “rational” is about making decisions. The “ratio” part suggests a parsing – a measuring and choosing of options. If we are choosing between options to make a decision, then the process must be directed towards a goal or set of outcomes.” When I read what you wrote here I thought of the scales used in measuring the weight of something…so we say that argument has weight, or a decision is “weighty” if a degree of wisdom is required for a good outcome.

    One problem I have is that “desired outcome” could in some cases imply an evil goal and Swedenborg frequently connects evil with falsity and insanity…negating what he would call “true rationality”.

    • George Gantz says:

      Thanks, Stephen – Yes, there are many trunks, branches and twigs we could follow. To play on this analogy, I am hoping we can prune off some of the dead stuff and follow the forks that lead to useful insights. On the question of emotions, I think there are several ways emotions should be included in considering rationality. One is the simple fact that a person feels a certain way about something – if my friend feels a certain way, I should certainly take that into account in making decisions about my relationship with him/her. Another example is that, as you point out, we weigh the value of different outcomes in making decisions – how we feel about something should certainly factor into our weighting. In both cases, however, it is important to be conscious of what our minds are processing in making a decision. If we are angry about something and make a snap judgement on the basis of that anger without “thinking it through” – that’s just acting on impulse and would not be rational. I think emotion and intuition (see for example Jonathan Haidt’s “The Righteous Mind”) are incredibly important to our decision-making – they are often quite challenging to tease out. This suggests it is actually quite difficult to achieve rationality (without bias). I hope to talk more about that later.

      The concern you raise with the quality of the desired outcome (good or bad) is also an important issue I hope to pick up later. So far, my discussion of rationality has been morally neutral (other than the presumption that being rational is better than being impulsive or random). The quality of our desired outcomes and intentions is another quite interesting consideration for another article. It may sometimes be the case that selfish motives are explicit and the resulting decision-making rational – this may be a case of confirming one’s evil, with dire consequences for the spiritual well-being of the person making those choices. More often, I suspect, the selfishness is hidden and the rational becomes, rather, a rationalization of a choice the person has already made secretly (perhaps even to themselves). There is a wonderful passage in Kurt Vonnegut’s Mother Night about the “skips” in the totalitarian mind that I will have to look up for that.

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