p Petzoldt has no better reason either for the reproaches he levels at Spinoza. He says: "Spinoza ... understands both substances, not as products of God’s creation, but as aspects of his being. God does not only think, he also has extension; he has not only 444 a soul, but also a body; he is identical with nature, i.e., for Spinoza, with the world. This pantheism signifies the lessening and perhaps the complete elimination of the power of the anthropomorphic conception of God, but it leaves untouched the main problem of the theory of cognition. For if to our philosopher matter and spirit are really not two distinct substances, but only attributes of the one and only substance of God, then for our problem this is essentially only a mere renaming of old concepts. We still do not know how material brain processes give rise to immaterial spiritual processes and vice versa, or how relationships conforming to law are established between these aspects which, even according to Spinoza, have nothing in common; and for the elucidation of all this it is a matter of indifference whether they are called substances or only attributes."  [444•* 

p No, it is not a matter of indifference; far from it. Difference in name is of no significance only where it is not accompanied by difference in the corresponding concept. To Spinoza, the new name means a new concept. In eliminating the doctrine of two substances, Spinoza expelled from the domain of philosophy that animism to which Descartes had paid such heavy tribute, to which every idealist pays equally lavish tribute, and which, in Petzoldt’s opinion (a justifiable one this time), constitutes one of the greatest errors of human thought. Further, It is strange to reproach Spinoza with not having explained how material brain processes give rise to immaterial spiritual processes. Did not the author of Ethics say outright that the second kind of processes are not caused by the first kind, but only attend them. "The soul and the body,” said Spinoza, "are but one and the same thing, conceived now under the attribute of thought, now under the attribute of extension."  [444•**  Take stock of these words of Spinoza and see if there is even an iota of sense left in the question of how spiritual processes are caused by corporeal processes. You see that the question is absolutely devoid of all meaning. The attribute of thought is not caused by the attribute of extension, but is simply the reverse side of "one and the same thing”, one and the same process. Petzoldt’s censure of Spinoza is tantamount to blaming this brilliant Jew for not explaining how one and the same process, conceived of from the angle of varying attributes, may present itself quite differently. But Spinoza never undertook this task. The fact that extension and thought are essentially two attributes of one and the same substance was for him an established fact, which explains many other facts, but is not itself subject to explanation. It is remarkable that the same Petzoldt credits 445 Spinoza with eliminating "the so-called interaction of body and spirit”. He says that having got rid of this interaction, Spinoza thereby prepared the ground for the latest views.  [445•*  But surely it must be clear that Spinoza could only have postulated the question of how material brain processes give rise to immaterial spiritual processes if he had recognised the interaction of body and spirit. Petzoldt reproves Spinoza for not tackling this question, and simultaneously) praises him for having refuted the interaction of body and spirit. A wonderful power of logic!

p Petzoldt avers that "already in Spinoza’s works we encounter the idea to which Leibniz later gave the appelation: pre– established harmony".  [445•**  As a matter of fact, Spinoza was spurned by the theologians of all countries, to use Lessing’s phrase, "like a dead dog”, because he had left no room in his philosophy for a being who could establish “harmony”.  [445•***  Petzoldt calls Spinoza’s teaching on the mutual relationship of thought and extension the doctrine of pre-established harmony. "Thus, two series of completely independent processes flow side by side.... When a physical phenomenon recurs, there will recur with it the spiritual phenomenon which previously manifested itself together with it,and vice versa."  [445•****  Well,isn’t it true? Isita“metaphysical” invention by Spinoza? A man drinks a bottle of vodka: that is a "physical phenomenon”. He gets drunk and all sorts of nonsense comes into his head: that is a "spiritual phenomenon”. Some days later he drinks another bottle of vodka: again a "physical phenomenon”. Once again he gets drunk, and again his head is filled with all kind of nonsense: this again is a "spiritual phenomenon”. "When a physical phenomenon recurs, there will recur with it the spiritual phenomenon which previously manifested itself together with it.” Surely everybody knows that? But what do the words "and vice versa" mean which Petzoldt attaches to the sentence I have just quoted? I must confess their meaning is beyond me. It must be that we have to see the example of the drunken man like this: the man gets drunk and the full bottle is found to be empty. Otherwise "and vice versa" is meaningless.  [445•*****  446 But however that may be, it is a fact that certain relationships conforming to law exist between psychical phenomena on the one hand and physiological phenomena on the other. Petzoldt himself, of course, does not deny this. But he finds that Spinoza explained these relationships badly. Let us agree with him for the time being and ask: are these relationships explained any better in idealist philosophy? Petzoldt will say no. What remains? “Modern” positivism! We turn to “modern” positivism.

p Petzoldt contends that the mistake of all philosophical teachings prior to this positivism consisted in the following: "They could not conceive of any other mutual dependence of natural phenomena than that of sequence in time: first A, then B; but not as in geometry: if A, thenB. According to the geometrical method, if the sides of a triangle are equal, then the opposite angles are also equal—If attention is directed to this completely general functional dependence of both geometrical and physical determining elements, then it is not difficult to conceive as analogous the relationships between spiritual and bodily phenomena (or determining elements), thereby bridging the gulf separating the two worlds. But Spinoza, although he set forth the basic principles of his main work and proved them, following strictly the model of Euclid’s geometry, and although he weakened the contrast between the two substances, reducing them to the level of two aspects of one and the same substance, nevertheless was very far from the aforesaid analogy. He was unable to think of parallelism between the spiritual and bodily processes in the form of the interrelation between x and y in the equation: y equals f (x), but needed a connective member between the two variable quantities, namely the conception of substance."  [446•* 

p So there we are: if A, then B’, if the sides of a triangle are equal, then the opposite angles are also equal. That is indeed very simple. 447 If a man has drunk a litre of vodka, then he has become intoxicated: which was to be proved. But does it answer the question with which Pet/oldt has just been pestering Spino/.a? Do we now know—thanks to “modern” positivism—“how” the given relationships conforming to law are established between A and B! Do we now know what determines the reciprocal relationship of spiritual and bodily phenomena? No, we do not. And it is all too clear that if we in turn began to worry Petzoldt with these questions, then he would decline to answer, on the ground that science discovers that phenomena are regulated by laws, but does not explain why there is this conformity to law. And he would be right. However, as the Germans justifiably say, was dem einen recht, ist dem-anderenbillig.  [447•*  Here also is a sort of "if— then”. // Petzoldt cannot be reproached for having an inclination towards the doctrine of pre-established harmony, then neither can Spinoza; for both of them leave one and the same question unanswered.

p The only difference is that Spinoza "needed a connective member between the two variable quantities, namely the conception of substance”, and Petzoldt did not. But it is now clear from what has been said that the difference is not at all in Petzoldt’s favour.

p In analysing Hume’s views on the relationship of the "inner world" to the external world, Petzoldt thus formulates his own theory on this subject: "Both worlds emerge from indifferent elements in the process of mutual differentiation and interrelationship. And this already indicates that they exist in relations of mutually functional dependence, while at the same time having a common independent root."  [447•** 

Whatever these "indifferent elements" may be, the differentiation of which leads, in Petzoldt’s words, to the emergence of the external world on the one hand, and the inner world on the other, one thing is clear: these two worlds have no sooner emerged than a relationship is established between them which is usually referred to as the relationship of the object to the subject. We already know just how badly the “new” positivism explains—or it would be better to say: how much it confuses—the conception of this relationship. Consequently, I shall not enlarge upon it. I will only remark that, here also, our author does not explain to us why certain reciprocal relationships are established between the “inner” world and the “external” world: that is to say, he is guilty— if one can speak of guilt in this case—of doing exactly the same thing he accused Spinoza of doing. However, there is a morsel of truth in the remark cited above. The two worlds really "do have a common root”. To the degree that this is correct, it comes 448 nearer to Spinoza’s doctrine that thought and extension are essentially two attributes of one and the same substance. Petzoldt is not in error only when he repeats the materialist doctrine of Spinoza which he has repudiated, albeit presenting that doctrine in an extremely muddled form.