Rationality and irrationality

Rationality / Irrationality (also called Shizotyme / Cyclotyme or Rigid / Labile) is one of the 4 Jungian dichotomies, and one of the 15 Reinin dichotomies. Rationality in socionics is a perceptual quality defined by a focus on actions and emotions. In contrast, Irrationality means a focus on states of mind and body.

Rational and irrational IM elements

Jung was the first to divide psychic functions into rational and irrational.

Rational functions are the judging ones Thinking (T) and Feeling (F).

Irrational functions are the perceiving ones Sensing (S) and Intuition (N).

Rational and irrational types

Rational types are defined as any type that has a rational element (T/F) in its first or leading function.
Irrational types are defines as any type that has an irrational element (N/S) in its first or leading function.

Rational types are: ESE, LII, EIE, LSI, LIE, ESI, LSE, and EII.
Irrational types are: ILE, SEI, SLE, IEI, SEE, ILI, IEE, and SLI.

In four-letter code, a rational type is denoted with a lower-case letter "j" at the end, while irrationals have "p".
For example, a type that has Ni in its first function (and Fe as second) is denoted as INFp. A type that has Fi in its first information channel (and Se in second) is denoted as ISFj.

Each quadra has two rational and two irrational types - a rational dual dyad and an irrational dual dyad.

Theoretical properties of rational and irrational types

In socionics, four IM elements are rational (Te , Fe , Ti , and Fi ), and four are irrational (Se , Ne , Si , and Ni ).

Rational types contain rational elements on accepting (odd) functions and irrational elements on producing (even) functions.
Irrational types contain irrational elements on accepting (odd) functions and rational elements on producing (even) functions.

Typical characteristics

Rationals

(Also called shizotymes in early socionics literature)

Tend to plan ahead, make decisions early.
Are more often rigid and stubborn.
Do not like to change their decisions.
Tend to finish what they started.
Usually have stiff movements.
Usually more 'authoritarian' leadership style.
Low stress tolerance.

Irrationals

(Also called cyclotymes in early socionics literature)

Tend to wait and see, more spontaneous.
Are more often flexible and tolerant.
Change their decisions frequently.
Tend to start new things without finishing them.
Usually have gentle movements.
Usually more 'democratic' leadership style.
High stress tolerance.

Additional Commentary and Notes

For the purpose of typing, it should be noted that no type is either completely rational or completely irrational. Every type in socionics contains a mixture of rational and irrational functions and, correspondingly, will display a mixture of rational and irrational traits. Thus, not one person fits neatly into one or the other side of this dichotomy, because every types has both rational and irrational functions.

The Rational-Irrational dichotomy also gets affected by type's subtypes. If the irrational function is accentuated in a person's type, then irrational traits will become more prominent, and vice versa for rational functions. This may pose a typing dilemma for creative function subtypes. Types are designated as Rational or Irrational based on their leading function, but a strongly expressed creative function obscures the leading function in this case. Thus creative subtypes may be mistaken for being the opposite of where their leading function actually places them on this dichotomy, e.g. an IEI-Fe may consider him or herself to be a rational type EIE, while an EIE-Ni may consider him or herself to be an irrational IEI. To resolve this dilemma, other type parameters should be taken into account and this dichotomy should not be used alone when deciding on type.

Additional Links

On the Correct Understanding of Dichotomy Rationality-Irrationality by Trehov and Tsypin