Rational Psychology

...we were testing the powers of the mind in establishing Rational Psychology.

§. 6.

Whether an error committed in Rational Psychology spreads further.

If an error is committed in Rational Psychology, no error spreads from it into Natural Theology, Logic, and Practical Philosophy. For in Rational Psychology, a rational explanation original: "rationalis ratio." In Wolff's system, this is the "sufficient reason"—the logical explanation for why something exists or behaves as it does. must be given for those things which are in the soul, or can be in it (§ 4). Since these things are taught in Empirical Psychology The branch of psychology based on observation and experience rather than pure deduction. (§ 2, Empirical Psychology), nothing is attributed to the soul in Rational Psychology except what is proven about it through the certain evidence of experience in the empirical branch. Therefore, if an error is admitted anywhere in the rational branch, it is not that something is attributed to the soul which is not actually there, or could not be there; rather, only a false explanation is given for that which is in it (or can be in it). In other words, a proposition that is known to be true a posteriori Knowledge derived from experience or observation. is simply demonstrated incorrectly. We use these propositions as our principles for proving other things, not the demonstrations themselves (§ 562, Logic). Therefore, even if an error is committed in Rational Psychology, no error spreads into these other disciplines alongside the principles that Empirical Psychology provides to Natural Law, Natural Theology, Practical Philosophy, and Logic (§ 6 and following, Empirical Psychology).

The fear of those who dream that some loss of virtue and justice in the state looms from Rational Psychology—should it happen to be erroneous—is empty. To dispel this fear, we have set down the present proposition. Does anyone fear that the human race will perish, with no more humans being born, simply because the theory of reproduction original: "generatio." handed down by a Physicist might not correspond to the truth? The hypothesis accepted until the time of Harvey William Harvey (1578–1657), the physician famous for describing the circulation of blood and investigating the development of embryos.—concerning the generation of man from the mixing of male and female seed into unformed masses, performed by the soul—is vastly different from the truth; today, nearly everyone who devotes effort to Physics acknowledges this...