When a human being acts, is it always in an internally logically consistent (i.e. rational) manner?

To answer this question, the assumption is that emotions are a part of our internal logic. We have an internal conception or model of the world, and that is both a mental and emotional model. Either my mental model or my emotions may not be a correct or good model with respect to how other people see the world, but my question is relative to the internal thoughts and emotions of the actor themselves - is the final choice that is made rational when considering how that person views the world.

There is some discussion of this here, especially how the emotions are a means of internalizing what we learn of the world, and using them as internal "input" into our decisions is legitimate as a source of input separate from our direct senses.

Now, I do understand this is a difficult area to really prove anything, but is there a general consensus, or possibly even different schools of thought on the matter?

Some areas I can think of that may be a counter example here:

  1. When we have no reference to the current situation. Is a baby, for example, really making rational choices when it is out exploring/learning about the world? That can be extended to adults in any unfamiliar situation.

  2. Spontaneous or "random" behavior. Why did I roll out of the other side of the bed this morning? Take a different way to work today? etc.

  3. "Snap" decisions due to lack of time, etc. Though this is likely fine as it could be described as rising from probabilities based on our experience in similar situations (i.e. best guess given the current data)

  • 1
    of course not. some human beings are crazy. some are self-destructive. some human beings are, by nature of their personality, unpredictable. sorta in the sense of a Monty Python sketch. Dec 22 '15 at 21:58
  • @robertbristow-johnson How is any of that not internally consistent with their thoughts, emotions, and sensory input at the time? A "crazy" person has possibly constructed their own internal world, a different version of reality - given that, aren't their actions always "internally consistent"? A suicidal person always has their reasons (i.e. the world would be better off without me, etc.). Is there any way to prove that they aren't being logical "within themselves"?
    – LightCC
    Dec 22 '15 at 22:03
  • not necessarily. they could be living in one constructed internal world, then a totally different constructed internal world, then perhaps the same world you and i live in. "unpredictable" is an observed human behavior. i don't know how to square the notion of "unpredictable" with that of "consistent". Dec 22 '15 at 22:23
  • @robertbristow-johnson That's sort of what I'm asking in the 2nd and 3rd examples at the end. By logically consistent, I mean that based on the totality of their internal motivations (thoughts and emotions) and external stimuli, do their actions make sense? Sort of - if we could actually have knowledge of someone's sensory input, thoughts and emotions at any given moment, would their actions always make logical sense (i.e. follow logically from the information or be rationally explainable)
    – LightCC
    Dec 22 '15 at 22:33
  • yeah, but if the person acts sanely nearly all of the time and then at totally unpredictable moments believes himself to be a radish, i wouldn't call that rationally explainable. Dec 22 '15 at 22:35

No. Humans do not act in an internally logically consistent way. In psychology and neuroscience, the phenomenon is called cognitive dissonance.

People often find themselves wanting contradictory things, the proverbial "Having your cake and eating it to".

People think they are acting upon conscious motives, when in fact they are driven by unconscious motives that make them behave irrationally with regards to their conscious ones.

People make decisions based on faulty logic all the time, or find themselves driven by emotions to commit acts against their better judgement.

People act in blatant contradiction to the ethics of one religion or another, while professing to be (and truly seeing themselves as) pious followers of said religion.

Probably the most glaring example though is drugs addicts: Many recovering drug addicts I have spoken to mention that when using in an advanced stage of addiction, they are fully aware of the destructive effect of their act yet are unable to resist the urge nonetheless. Although in the initial stages they might rationalize or glamorize the abuse, they get to a point when they sink very deep into their addiction, where they know exactly what they are doing, but have lost their will power completely and cannot pull themselves out of it without outside help. This is apparently especially strong with Heroin addicts, where the urge to use, takes a person over completely and they are simply unable to fight it.

Added in response to OP's comment One might go so far as to say that even an addict's behavior still conforms to some internal logic, with the urges and emotions induced by the drug acting as inputs, and the final behavior still consistent given the inputs. This implies then that emotions are somehow separate from thoughts, but I think that emotions and thoughts are much more interactive than that and such a separation is impossible. Can someone think about an ethical or moral issue without their emotions regarding that issue influencing the thought process? I doubt such impartiality is possible - those who do act against their emotions have to exercise great effort in doing so.

But let's assume you're right, and emotions are indeed separable from thoughts. Even then, there are cases of denial, people suffering from shock, people have psychotic episodes due to PTSD.

One can adopt a computational theory of mind (you are assuming the mind follows some internal logic), and compare the situation to that of computers: What happens when a computer goes into a logical inconsistency? It crashes or goes into an infinite loop, or freezes. It ceases to function, and it calculations are interrupted. This is exactly what happens to people who face experiences so traumatic that they become delusional, catatonic, unresponsive to external stimuli, schizophrenic, etc...

  • Interesting take. I suppose it still looks internally consistent to me in that we can still explain his behavior - i.e. his urges overrode his mental concepts and "won", thus we see the final behavior. But I agree he had contradictory inputs in the first place. Of course, from that perspective, we all have contradictory inputs at times and in varying measures - are you claiming that anytime our emotions/urges override our thoughts/mind that it should be characterized as irrational?
    – LightCC
    Dec 22 '15 at 23:18
  • @LightCC see edit to the answer. Dec 23 '15 at 2:56
  • (Based on the extra edit): I'm not sure that we can say the mind is the part of us always making the decision - at least the conscious mind, a lot of this (such as the interaction of the mind and emotions) is really taking place at a sub-conscious level, and it seems we don't always have conscious control of the final choice we make. This is a really interesting area, but not what I originally thought I was asking about! i.e. how do humans resolve inconsistencies of both internal and external stimuli.
    – LightCC
    Dec 23 '15 at 3:20
  • People conflate cognitive conflict and cognitive dissonance too freely. Cognitive dissonance has to be something of which you fail to be consciously aware, at least in sense of the originators of the term. Otherwise the basic fact of cognitive dissonance theories "Cognitive dissonance alters current values to better predict past behavior" becomes false. If you are conscious of the conflict, you can choose your values consciously and ecape the effect.
    – user9166
    Dec 30 '15 at 17:27

Typically, no. The key question is: is a human logically consistent? Can you come up with examples of humans that have been logically consistent from birth to death? Can we come up with one example? If we cannot come up with an example of a human that has been logically consistent at all times, then we cannot claim "human beings always act rationally."

If you keep digging at the question, you can arrive at a tautology. If you define "internally consistent" as "doing what you were going to do," then most will agree that humans are internally consistent, as are dogs, cats... heck, really all animals plants and rocks are "internally consistent" by that definition.

An interesting question may be therein: at what point in modeling do we transition from being inconsistent to consistent? Is it a point, or something else?

My personal opinion is that the point where you can start arguing that the system is consistent is the point where you start treating the entity as a distributed entity with many independent parts, but at that point "internally consistent" becomes a complicated concept.

  • Yes, I'm seeing that is perhaps the deeper question - first, address: What does it mean to be logically consistent? I suppose my definition comes close to the "what you were going to do anyway", but I was thinking of it in terms of internal/external inputs and free will. In other words - can free will allow me to go against "what I was going to do anyway"? Maybe Alexander S King is right... :)
    – LightCC
    Dec 23 '15 at 2:37
  • It all depends on your definitions. Some definitions of freewill allow you to "go against your nature," others do not. Of course, until you truly know yourself, the deeper question becomes indistinguishable from the shallower one.
    – Cort Ammon
    Dec 23 '15 at 3:32

By self-observation almost everyone can answer this no. Our emotional systems are simply not consistent within themselves, and do not lead to consistent thinking or behaviors unless we work very hard at suppressing different aspects of ourselves at different times.

This is to be expected, as I see it. It is an important aspect of animal decision making. If we rushed toward consistency, we would not effectively explore the solution space around our options. In practice, most heuristic solution systems can work considerably faster with random perturbation than planned coverage. Some of our best solution methods in the past, like genetic algorithms, derive almost all of their effectiveness by simulating pseudorandom conflict.

Look at something as straightforward as linear programming. The simplex algorithm, which is known to have an exponential running time, will always get a solution in polynomial time if you just throw in a little random noise whenever it appears slow. A much better, proveably quadratic-time solution to the same problem, that needs no perturbation has been around for half a century, but still gets less use.

Nonrandom solution processes are especially bad when the problem is overdetermined, so that solutions are actually plentiful, but good solutions lie very near to inconsistent ones. (Climbing a hill riven with cracks and cliffs is hard.)

A lot of the input to our solution processes are self-contradictory, so our goals are often very much overdetermined. How can a solution be consistent with a system that is already overdetermined and therefore self-contradictory?

Knowing this it is a little strange to me that we have invested so little concern in paraconsistency.

Perhaps "consistency is the hobgoblin of small minds" because it keeps them small.

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