Sigmund Freud on Franz Brentano (& other philosophers)


My report that I intended to change over to the philosophical faculty must be amended inasmuch as it was my original plan to combine attendance at two faculties and to take both doctorates in three to four years. This, however, is impossible, at least the first part; I shall have to make closer inquiries about the second. In any case, I am free to take zoology, my main subject, in the philosophical faculty and to attend philosophy lectures whenever I please, which is what will happen next semester. Naturally, a Ph.D. examination remains a possibility and tomorrow I and Paneth, who is involved in these plans, will be seeking Brentano’s advice.

To give you a clearer idea of the course of my studies, I am setting down the schedule for the summer semester, as I intend to follow it with few if any changes.

7-8          M, Tu, W, Th, F     Vertebrate Anatomy
7-9          Saturday                 Mollusc anatomy
9-11        M, TU, W              optics (theoretical and experimental)
9-11        Th, Friday               Physiology laboratory
11-12      M, Tu, W, Th, F     Physiology
9-12        Saturday                 zoology practicum
12-1        M, Tu, W, Th, F     Organic chemistry
1:30-4     three times a week   Physiology laboratory
1:30-6     twice a week           Physiology laboratory
4-6          twice a week           Logic (with Brentano)
6-7          Saturday                 Philosophy lecture by Brentano

As you can see, I am not short of courses, almost all of them stimulating, and if I manage to do everything as I have set it out, the semester will be a model of how to spend one’s time. And there is still time left over to loll about in the bath for an hour before taking supper at the Hirsch, for there is no study at night, except for lectures, though I do plan to read various things on philosophy and natural history.

“And thus we live, thus fortune guides our steps,” though Fried. Nietzsche took David Strauss to task in Strasbourg for this philistine dictum in 1873. [3] Of my relationship with Brentano, which you may be imagining as closer than it really is, and of the philosophical outlook I have derived from it, I shall write to you tomorrow, when our visit to him, at ten o’clock, is over.

Monday, March 15

Below, an account of that visit, given at length, the better to convey an idea of the man and our relationship to him. The beginning of the conversation was about the weather and an accident Paneth had witnessed; next, he brought out our letter and wanted to refute our objections, which was still necessary only in one case, however. Then he made a few quite favorable remarks about our endeavors, saying he was glad that we were so keen to acquire greater knowledge and that, though of the opposite opinion to him, we did not allow prejudice to stand in our way (he knows perfectly well that we are materialists). He complained that philosophy was in absolute chaos here, whereupon Paneth, who had attended Zimmermann’s lectures, made some highly disparaging remarks about the latter, thus forcing Brentano to pronounce on Herbart. [4] He utterly condemned his a priori constructions in psychology, thought it unforgivable that Herbart had never deigned to consult experience or experiment to check whether these agreed with his arbitrary assumptions, declared himself unreservedly a follower of the empiricist school which applies the method of science to philosophy and to psychology in particular (in fact, this is the main advantage of his philosophy, which alone renders it tolerable for me), and mentioned a few remarkable psychological observations that demonstrate the untenability of Herbart’s speculations. There was much greater need for thorough research into individual questions, the better to arrive at reliable individual conclusions, than for attempts to tie up the whole of philosophy, which was futile because philosophy and psychology were but young sciences and could expect no support from physiology in particular. When we asked for personal advice, he told us that it was quite feasible and a good idea for us to attempt a doctorate in philosophy as well as in medicine, and that this was not unprecedented—Lotze [5] had done just that and had then opted for philosophy. We would do well to specialize in a philosophical subject; the Minister had enjoined him to train lecturers in philosophy. (Though we are unlikely to take him up on this.) From among philosophical writers he selected some he advised us to read and took the rest to task mercilessly. We ought to start with Descartes, and study all his writings because he had given philosophy a new impetus. Of his successors, Geulinx, Malebranche, and Spinoza, [6] none was worth reading. All of them had picked up the wrong end of Descartes’ philosophy, his complete separation of body and soul. Spinoza indulged in pure sophisms; he was to be trusted least of all. Locke and Leibnitz, by contrast, were indispensable, the first being a most brilliant thinker, the second not fully satisfactory only because he tended to dissipate his strength. These two were succeeded by the popular philosophers, who were of purely cultural and historical, not philosophical, interest. By contrast, two figures from the skeptical period, Hume and Kant, were indispensable, Hume being the most precise thinker and most perfect writer of all philosophers.

Kant, for his part, did not at all deserve the great reputation he enjoys; he was full of sophisms and was an intolerable pedant, childishly delighted whenever he could divide anything into three or four parts, which explains the inventions and fictions in his schemata; what people praise in him Brentano was ready to credit to Hume, what is entirely Kant’s own he rejected as harmful and untrue. In short, Kant comes off very badly in Brentano’s eyes; what makes Kant important is his successors, Schelling, Fichte, and Hegel, whom Brentano dismisses as swindlers (you can see how close he comes to the materialists in this regard); he told us how discouraged he felt in his youth, when he started to read philosophers, how he nearly despaired of his philosophical talent until he was made aware of his abilities by [?] an older philosopher.

“And so you want to let us off without reading them?” I asked. More than that, I want to warn you against reading them; do not set out on these slippery paths of reason—you might fare like doctors at insane asylums, who start out thinking people there are quite mad but later get used to it and not infrequently pick up a bit of dottiness themselves. Of the most recent philosophers, he then recommended Auguste Comte, whose life he described to us, and he was about to go on to the English philosophers when Prof. Simony [7] turned up and we were packed off, with permission to call again during the “vacation” and to fetch him for a walk.

So far, so good, and you might flatter yourself on having a friend thought worthy of the company of so excellent a man, were it not that thousands of others have been invited to his home or to converse with him, which greatly detracts from our distinction. He came here to found a school and to gain disciples, and hence proffers his friendship and time to all who need it. For all that, I have not escaped from his influence—I am not capable of refuting a simple theistic argument that constitutes the crown of his deliberations. His great distinction is that he abhors all glib phrases, all emotionality, and all intolerance of other views. He demonstrates the existence of God with as little bias and as much precision as another might argue the advantage of the wave over the emission theory. [8]

Needless to say, I am only a theist by necessity, and am honest enough to confess my helplessness in the face of his argument; however, I have no intention of surrendering so quickly or completely. Over the next few semesters, I intend to make a thorough study of his philosophy, and meanwhile reserve judgment and the choice between theism and materialism. For the time being, I have ceased to be a materialist and not yet a theist. Though he upholds man’s descent from the animals, he opposes Darwinism and has shattered my own belief in it, not so much with his own arguments as with the report that the computations of Thomson [9] in London have demonstrated that the organic history of the earth could not be put at more than one hundred million years, but even if Darwinism stands up, as I hope it does, it does not conflict with his teleology or with his God.

3. The quotation is from Goethe, Zueignung (Dedication). David Friedrich Strauss (1808-1874), in Das Leben Jesu, kritisch bearbeitet (The life of Jesus, considered critically), presented the Gospels as the unconscious product of the primitive Christian communal spirit. Nietzsche (who worked in Basel, not Strasbourg), commented on this view in Untimely Meditations, I.4.

4. Johann Friedrich Herbart (1776-1841), best known as the father of scientific pedagogy based on psychology. Tr. Robert Zimmermann (1824-1898), appointed Professor of Philosophy at Vienna in 1861, was a leading Herbartian.

5. Rudolph Hermann Lotze (1817-1881), appointed Professor of Philosophy at Leipzig in 1842 and at Göttingen in 1844, described his philosophy as “teleological idealism.”

6. Arnold Geulincx(1625-1669) developed the doctrine of occasionalism; as a metaphysician, Nicolas Malebranche (1638-1715) stands between Descartes and Spinoza.

7. Friedrich Simony (1813-1896), appointed Professor of Geography at Vienna in 1851.

8. Theories of light by Huygens and Newton, respectively.

9. William Thomson, Lord Kelvin (1824-1907) taught in Glasgow, not London.

From: Letter to “¡Querido Berganza!”, Vienna, March 13, 1875, from Cipion, pp. 101-105.


For the homoeopathic papers you sent me, many thanks! Previously I had read but little and I have now found that my expectation of being served up utter nonsense was not fulfilled; yet it is no great achievement to remain on the well-trodden path of common sense for ten pages. So far, I can conclude only that these gentlemen are great metaphysicians, and Kantians in particular, which is most laudable but perhaps unhealthy. We shall see. They say Leipzig is the main center of homoeopathy. [2]

I can hardly convey to you how greatly my faith in what is generally held to be correct has been shaken and how much my secret leaning toward minority views has grown. Ever since Brentano adduced such ridiculously simple arguments in favor of his God, I have been afraid that one fine day I will be taken in by the scientific proofs of the validity of spiritualism, homoeopathy, by Louise Lateau, [3] etc. In short, I have been too little of the dogmatist, adhering to all I believed in out of logical conviction alone.

Your appreciation of Brentano is uncommonly good and you may accept my compliments for assessing the main features of my relationship to him so accurately. Indeed, his God is a mere logical principle and I have accepted it as such. He repudiates any direct intervention by God on the grounds that it would be dysteleological. How far he allows regard for God to affect life is still unclear, though as far as I remember he once hinted at something like that in ethics. And I still have to find out what he thinks of ritual and a thousand other things that are more important in practice than his empty God concept. Unfortunately, when we allow the God concept we start down a slippery path. We shall have to wait and see how far we fall. His God is a most peculiar one. Since he claims that man knows very little of the world, perhaps stopping short at the Dubois-Reymond limits of cognition, [4] he may be forgiven for crediting God with even less knowledge. Man lacks a proper conception of God and can approach it only by analogy; it cannot be reached by human calculation. Confusing though it all seems, it is nevertheless closely reasoned, and madly methodical. In short, Brentano cannot possibly be refuted before one has heard and studied him and plundered his stores of knowledge. So sharp a dialectician requires one to hone one’s own wits on his before challenging him.

2. Leipzig had a homeopathic hospital and was the seat of the Central Association of German Homeopaths.

3. Louise Lateau (1850-1883), daughter of a Belgian railway worker, allegedly manifested the stigmata in 1868.

4. Refers to a lecture delivered in Leipzig in 1972 entitled “Über die Grenzen des Naturerkennens” (On the limits of our understanding of nature).

From: Letter to “Dear Friend,” Vienna, March 27, 1875, from Cipion, pp. 106-107, 108.


With you, too, signs and wonders never seem to cease. You seem to be waging a struggle with yourself, one, that is, of a much more serious nature than were your previous Werther and Lotte conflicts. You are searching for truth in life with the same urgency as I try to seek [it] in science. The big question you must be asking yourself daily is, Third or Fourth Estate? Republican or Social Democrat—for me it is theist or materialist, causality or skepticism. Still, you must find it more pleasant than I do; you are about to become a neophyte while I am almost a convert.

For the time being, I have to confess that I badly mistook the basic questions that agitate me, and that I was completely lacking in philosophical insight. The rueful confession of a former swashbuckling, stubborn materialist! But even in my new coat I feel anything but comfortable, and have thought it best to defer a final decision until such time as I may be more versed in philosophy and more mature in science. Perhaps you will find my example worth emulating. It would seem that contact with the social democrat[s], from which you did not at first expect any effect on your convictions, nevertheless made a fairly marked impression on you. In any case, you are wrong to think that social problems and your approach to them or your contacts with the Leipzig crowd leave me indifferent; they interest me most keenly, and I hope you will let me have regular and detailed reports on the matter. The fact that they have turned their views into dogma, and permit no discussion of it, seems to be no recommendation for them, and certainly not the right way to attract adherents from the learned estate. The unshakability of their convictions, which you praise, is the worst possible proof of their validity, for all their claims and hopes are based on these very theories.

I have read the A.B.C. des Denkens für Wissende [1] with interest and would like to make a few comments on it, on the assumption that you have read it as well.

I can be brief, and cite Dr. Douay himself as admitting it was legitimate to assume that God exists. “Nothing is true,” we read, “but what can be proven by the evidence of one’s senses or rests on previously proven propositions.” In the second part of the sentence lies the proof of God’s existence. Were the proven propositions of science, the law of causality, to demand the existence of God, then, Dr. Douay concedes, he could not object. But Kant, the most level-headed of all philosophers, is supposed to have presented four proofs a hundred years ago refuting most incisively the possibility that a God exists. [2] This seems to be clearly wrong; Kant did refute the three or four proofs of God’s existence, but he adduced only one refutation of all possible proofs, which is connected with the fundamental assumption of his system, namely of synthetic a priori judgments. Now, it is not very nice of Dr. Douay to use philosophy as a scarecrow when it suits him, and otherwise in a purely speculative question to silence her. Perhaps he has read Kant’s Critique of Practical Reason and discovered that the most thoughtful of all philosophers cannot dispense with a God, even though he cannot prove His existence. Nor is it correct that Kant’s proof has gone unchallenged; his proof rests on the assumption of synthetic a priori judgments and stands or falls with them. Now, a large and truly scientific school, that of the English empiricists, decisively rejects the possibility of such judgments. “All our knowledge not only begins with, but also springs from, experience,” [3] they claim, which sounds materialistic enough, and is in any case more scientific than the idea of innate forms of understanding. If, therefore, the social democrats are so keen on Kant’s irrefutable proof, then let them stand up and champion the existence of a priori synthetic judgments and establish whether the nature of causality is analytic or synthetic. For let them not be deceived, the existence of God cannot be settled by union debates, parliamentary speeches, or speculation, but only by logical and psychological studies, for which not everyone has a taste, no more so than for astronomical computations. Hence it is just as wrong to think everyone is competent to pronounce on the existence of God as on the existence of Neptune. [4] Once logical analyses have led to a certain conclusion, the existence or nonexistence of God will be as firmly established as that of Neptune, and will have to be accepted as unreservedly by all who do not happen to be philosophers or mathematicians. However, the analyses will have to show whether the nature of the object and of the arguments admit of such certainty in the first place.

The other popular arguments against God have been mustered with great incisiveness and I am indeed most curious to discover how the theist, Brentano, will deal with them. Inasmuch as he considers God a logically necessary scientific hypothesis, he may perhaps skirt the issue, saying: we do not know much about God, our conclusions lead us as far as Him but no further, so that all the evil in the world, whose full range we do not comprehend either, cannot be used to refute Him. More of that later.

The bad part of it, especially for me, lies in the fact that science of all things seems to demand the existence of God (I say seems, for the result of this analysis is partly dependent on logical analyses). The principle of the conservation of energy, of the interaction of natural forces, which we consider as the best fruits of scientific research, seem to involve the end no less than the beginning of the world. According to a verbal report by Brentano, Prof. Fick (physiologist) of Würzburg not only granted this fact but also emphasized it in his lectures on the above laws. [5] We are completely powerless in the face of attacks from that quarter.

But let us cut our philosophical deliberations short. I cannot promise that I shall still be holding these views next week. You may not perhaps attach enough importance to the whole matter to justify so lengthy an account in a friendly letter.

1. Adolf Douai 1819-1888), ABC of knowledge for thinking people, Leipzig, 1874. Douai, a schoolteacher, published Volkskatechismus der Altenburger Republikaner (Popular catechism of the Altenburg Republicans) in 1848; following a year’s imprisonment, he emigrated to the United States, where he worked as an editor and teacher.

2. Douai wrote: “Kant, the most thoughtful of philosophers, proved incisively, almost a hundred years ago, that there could be no valid proof for the existence of God.”

3. John Locke, An Essay concerning Human Understanding, II.1.2: “In that [i.e., experience] all out knowledge is founded and from that it ultimately derives itself.”

4. The existence of the planet Neptune was postulated in 1823 by Friedrich Wilhelm Bessel (1784-1846); the planet itself was not sighted until 1846.

5. Adolf Fick (1829-1901), Die Naturkräfte in ihrer Wechselbeziehung (The interaction of natural forces), 1869.

6. Victor Ofenheim (1820-1886), a railway magnate, was made the scapegoat for the stock exchange collapse of 1873, in particular by Austrian anti-Semites. His trial in 1875 ended in acquittal.

7. A national-liberal Viennese daily, it carried reports on the Ofenheim trial from January 3 to February 28, and from March 10 to April 11, 1875.

8. Johannes Immanuel Volkelt (1848-1930), Kants kategorischer Imperativ und die Gegenwart (Kant’s categorical imperative and the present), 1875. The lecture was delivered on March 10.

9. For the rest it is my opinion; from Cato’s dictum Ceterum censeo Carthaginem esse delenda (For the rest it is my opinion that Carthage must be destroyed). Tr.

From: Letter to “Dear Friend,” Vienna, April 11, 1875, from Sigismund, pp. 109-111, 113.


I sent the list of lectures you asked for yesterday, and I am sorry that it will be several weeks before you come to Vienna, because next semester I shall have much to do; no less than eight examinations are waiting for me and I have done no, or practically no, studying so far. The philosopher Brentano, whom you know from my letters, will lecture on ethics or practical philosophy from eight to nine in the morning, and it would do you good to attend, as he is a man of integrity and imagination, although people say he is a Jesuit, [2] which I cannot believe, trusting my own judgment rather than rumors spread by Mr. So-and-So.—

In Spanish

     2. Silberstein did attend this lecture; Brentano was not only no Jesuit, but left the Church in 1873.

From: Letter to “Dearest Berganza,” Vienna, September 19, 1875, from Cipion, p. 129.


SOURCE: The Letters of Sigmund Freud to Eduard Silberstein 1871-1881, translated by Arnold J. Pomerans, edited by Walter Boehlich (Cambridge, MA: The Belknap Press of Harvard University Press, 1990), pp. 101-105, 106-107, 108, 109-111, 113, 129. [Eduard Silberstein (1857-1925).]


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