What is Private Logic
Exterior life-style and alignment towards the final goal are supported by an interior and idiosyncratic private logic. Private logic comprises the values and beliefs upon which a person operates. It, too, is created in childhood and may contain oversimplifications, generalisations and distortions, especially when progress towards the final goal is jeopardised or thwarted. Private logic is the domain of biased apperception rather than common sense.
Attitude towards life evidently determines behaviour, and the insidiously “tight” and barely negotiable assumptions of dysfunctional private logic may create damaging self-fulfilling prophecies. Life and people turn out as expected.  An early decision to perceive others as untrustworthy, for example, elicits the very responses that confirm the initial hypothesis and hence reinforce it. Similarly, there is the well documented concern that some witnesses in court tend to adopt a particular stance which transcends and may ultimately seek inadvertently to distort presentation of factual evidence.
Private logic is valuable since it protects the unity of the personality in the face of the uncertainty and fluidity of experiential reality. In order to do so, however, safeguarding tendencies – the Adlerian counterpart of psychoanalytic defence mechanisms – may be invoked (refer to Psychological Disturbance, line 226). Private logic, in a sense, is the “cognitive glue” holding together the personality, in significant part by precluding reactivation of feelings of inferiority. Adler sought to encourage the replacement of private logic by the ironclad logic of social living.