or immediate consciousness (he who loves, knows what love is; it is a per conscientiam et intimam experientiam notissima res); the praiseworthy attempt to give a systematic arrangement, according to their derivation from one another, to the innate mathematical concepts, which Descartes had simply co-ordinated (the concept of surface is gained from the concept of body by abstracting from the third dimension, thickness—­the act of thus abstracting from certain parts of the content of thought, Geulincx terms consideratio in contrast to cogitatio, which includes the whole content); and, finally, the still more important inquiry, whether it is possible for us to reach a knowledge of things independently of the forms of the understanding, as in pure thought we strip off the fetters of sense.  The possibility of this is denied; there is no higher faculty of knowledge to act as judge over the understanding, as the latter over the sensibility, and even the wisest man cannot free himself from the forms of thought (categories, modi cogitandi).  And yet the discussion of the question is not useless:  the reason should examine into the unknowable as well as the knowable; it is only in this way that we learn that it is unknowable.  As the highest forms of thought Geulincx names subject (the empty concept of an existent, ens or quod est) and predicate (modus entis), and derives them from two fundamental activities of the mind, a combining function (simulsumtio, totatio) and an abstracting function (one which removes the nota subjecti).  Substance and accident, substantive and adjective, are expressions for subjective processes of thought and hence do not hold of things in themselves.  With reference to the importance, nay, to the indispensability, of linguistic signs in the use of the understanding, the science of the forms of thought is briefly termed grammar.

The principle ubi nihil vales, ibi nihil velis, forms the connection between the occasionalistic metaphysics and ethics, the latter deducing the practical consequences of the former.  Where thou canst do nothing, there will nothing.  Since we can effect nothing in the material world, to which we are related merely as spectators, we ought also not to seek in it the motives and objects of our actions.  God, does not require works, but dispositions only, for the result of our volition is beyond our power.  Our moral vocation, then, consists in renunciation of the world and retirement into ourselves, and in patient faithfulness at the post assigned to us.  Virtue is amor dei ac rationis, self-renouncing, active, obedient love to God and to the reason as the image and law of God in us.  The cardinal virtues are diligentia, sedulous listening for the commands of the reason; obedientia, the execution of these justitia, the conforming of the whole life to what is perceived to be right; finally, humilitas, the recognition