# Science versus pseudoscience: What about contradiction in projective tests? - continued

Posted 11/12/2012

This note is being addressed to persons who do not know the logic, as a supplement for previous note. Some words about contradiction in logical rules of inference. If we have for example, such expressions:

p **← **q1

p **← **q2.

they are quite correct in logic and obviously are not contradiction, they are simply equivalent to the following alternative:

p **← **q1 ˅ q2.

The sign of the implication can be reversed as follows: → . It is allowed, and the way of writnig logical expressions presented above is typical for eg. logic programming. It does not matter for our problem.

The contradiction we have in the following situation in logical rules:

p **← **q

¬p **← **q.

Now, we have classical contradiction in rules which can be used eg for further inference/reasoning by psychologists (believers in Rorschach "test"). In practice, analysing personality if much more conditions has to be taken into account, the expression should be in more general form as follows:

p **← **q1 ˄..˄ qn,

where p, q1,.., q2 are propositions or predicates. Here we have the Horn clauses syntax as simplest version of rule.

Nota bene, the situation is somewhat analogous to the IQ test - may be the test something tests, the quetsion is what ?! if we do not have a good definition of intelligence, how can we measure something up of what aren't we able brightly to define? Absurdity!