## 1. Brief Biography




Hans (born Johannes) Vaihinger's early life was in many ways
that of a typical intellectual in nineteenth-century Germany. Born on
25 September 1852 near Tubingen, the son of the pastor Johann
Georg Vaihinger, Hans was intended for the clergy. He began his
studies in theology at the University of Tubingen in 1870, but,
never especially devout, he soon turned his attentions to other
subjects, primarily philosophy and natural science. Throughout the
next four years, Vaihinger's course of study emphasized the
classics of German philosophy--Kant, Fichte, Schelling, Hegel,
and Schleiermacher--but he also devoted himself intensely
to the independent study of Schopenhauer and Darwin. In 1874,
Vaihinger completed his dissertation under the supervision of the
logician Christoph von Sigwart with a prize-winning essay,
entitled *Recent Theories of Consciousness according to their
Metaphysical Foundation and their Significance for
Psychology*.




Later in the same year, he reported to Leipzig for compulsory military
service, but was excused due to his poor eyesight. Free of his
military duties, Vaihinger had the opportunity to attend lectures at
the University from, among others, the founder of empirical psychology
Wilhelm Wundt. It was during this time that Vaihinger first
encountered the work of a figure who, next to Kant, would be his most
important and lasting philosophical influence, the Neo-Kantian
Friedrich Lange. Vaihinger describes the impact
Lange's *History of Materialism* made on him as follows:
"Now at last I had found the man whom I had sought in vain
during those four years [at Tubingen]. I found a master, a guide,
an ideal teacher... . All that I had striven for and aimed at
stood before my eyes as a finished masterpiece. From this time onwards
I called myself a disciple of F.A. Lange" (*PAO*,
xxi-xxii).




After a brief tenure in Leipzig, Vaihinger moved to Berlin, where he
continued his studies with Hermann von Helmholtz and the Neo-Kantian
Eduard Zeller. In 1876, Vaihinger published his first work, an
exposition and defense of Lange's brand of Neo-Kantianism,
entitled *Hartmann, Duhring, and Lange: Towards a
History of German Philosophy in the Nineteenth Century*. It was
here that the views which would form the basis of the *PAO*
first began to take shape. In autumn of the same year, Vaihinger again
relocated--this time to the University of Strassburg--and by
early 1877 he had habilitated with a work entitled *Logical Studies
on Fictions. Part I: The Theory of Scientific Fictions*. Though the
*PAO* would not be published for more than 30 years, the
*Logical Studies* is already, according to Vaihinger,
"exactly the same" as Part I of the former work
(*PAO* xxiii-xxiv).




The extremely long gestation period of the *PAO* seems to
have been the product of a variety of factors. First and foremost,
monetary considerations compelled Vaihinger to find permanent academic
employment. To further his candidacy, Vaihinger decided to bring out a
*Commentary on Kant's Critique of Pure Reason* in honor of
the centenary of the first *Critique'*s publication. The
first volume of the *Commentary* was released in 1881, and
helped Vaihinger secure a permanent position at the University of
Halle. The second volume followed in 1892. A sense of the scholarly
depth of Vaihinger's work is given by the fact that the
two-volume *Commentary*, which deals only with the
*KrV*'s Prefaces, Introductions, and Transcendental
Aesthetic, reaches nearly 1,100 pages. Moreover, a number of personal
and professional engagements occupied Vaihinger in the last decade of
the century. In 1889 he married Elisabeth Schweigger, the daughter of
a Berlin bookseller. In 1892 they had a son, Richard, and in 1895 a
daughter, Erna. In 1896, he founded the journal *Kant-Studien*,
and in 1901 the *Kant Gesellschaft*.




Finally, in 1911, Vaihinger published the first edition of
*PAO*. The work made him something like a philosophical
celebrity virtually overnight. It proved so popular that it had gone
through no fewer than 10 editions by the time of his death in 1933,
attracting the attention of luminaries from a wide variety of academic
fields (including Einstein, Ostwald, and Freud). Halle even became
informally known as the "Vaihinger-Stadt" (Vaihinger
city). The *PAO*'s success enabled Vaihinger to found,
in 1918, yet another journal, *Annalen der Philosophie und
philosophischen Kritik*, which dealt specifically with the themes
broached in the
*PAO*, and included contributions from figures such as the
mathematician Moritz Pasch, the embryologist Wilhelm Roux, and the
positivist philosophers Rudolf Carnap and Hans Reichenbach. In 1930,
Carnap and Reichenbach took over editorship of the *Annalen* and
renamed it *Erkenntnis*. 




Though this period of Vaihinger's life was marked by tremendous
professional success, it was also a period of personal struggle. In
1906, suffering badly from cataracts, Vaihinger was forced to
discontinue his lecturing. Eventually, he was completely blinded. In
1913, there occurred a rather bizarre incident: an anti-Semitic
publication, the *Semi-Kurschner*, "accused"
Vaihinger of being a Jew. With anti-Semitism already on the rise in
Germany, Vaihinger felt compelled to defend his reputation in court,
and sued the publication for defamation. Though the
*Semi-Kurschner* ultimately removed his name, the incident
perhaps explains in part why his reputation would continue to suffer
under the Nazis. Additionally, Vaihinger had invested significant
portions of his assets in Russia; the October Revolution, together with
the economic crisis after the First World War left him in dire
financial straits, and he was forced to sell the bookstore he had
inherited from Elisabeth's parents. Struggle turned to tragedy
when, in 1918, Vaihinger's daughter Erna committed suicide. His
son Richard also began suffering from neuropathy brought on by the war,
and by 1929 he was completely incapacitated.




Vaihinger died in 1933, on the eve of the rise of the Third Reich. A
long-time liberal and pacifist, Vaihinger and his work were treated
with hostile silence throughout the Nazi period. A final, posthumous
tragedy would thus befall him during these years: once among
Germany's most celebrated and influential philosophers,
Vaihinger became a virtual nobody, and his works were quickly
forgotten. Though contemporary philosophical literature reveals a
renewed interest in his ideas, it is fair to say that his reputation
has never fully recovered. For a more detailed treatment of
Vaihinger's biography, see (Simon 2014). Vaihinger himself
discusses his intellectual development at length in his
autobiographical (1921b) (also included as the introduction to
C.K. Ogden's 1925 English translation of
*PAO*).


## 2. Early Views and Intellectual Context




With the hegemony of absolute idealism broken, Germany was awash with
competing philosophical systems by the time Vaihinger habilitated in
1877. Three important movements are worth emphasizing (for detailed
studies of the late nineteenth-century context, see Beiser [2013;
2014; 2015; 2017]). First, under the influence of Lange and others,
Neo-Kantianism had become a major force on the intellectual
scene. Second, due partly to Schopenhauer's rising star, and
partly to the continued influence of Hegel and Schelling, grand
metaphysical theorizing after the idealist model was experiencing a
resurgence in the work of Adolf Trendelenburg, Hermann Lotze, and
Eduard von Hartmann. Finally, traditional materialism and empiricism,
though very much on the defensive, had nevertheless gained back
considerable ground since their nadir in early decades of the
century.




Vaihinger's first intervention in these foundational debates
came in the form of his short tract *Hartmann, Duhring, and
Lange*. Its title notwithstanding, the book is less a work of
historical exegesis, and more a polemical defense of Lange's
Kantian standpoint against the dual assault of naive realism
(represented by the positivism of Eugen Duhring) and unchecked
metaphysical speculation (exemplified by Hartmann's
Neo-Schopenhauerian view, according to which fundamental reality is a
monistic vital substance). Vaihinger's chief charge against
Hartmann and Duhring is that they are *dogmatists*, that
they systematically overstep the critical strictures Kant had placed
on cognition, claiming knowledge of things in themselves (1876, 10,
17). Both commit "the original sin of *post-Kantian
philosophy*"--Hegel's
"fantastic *petitio principii*" of "the unity
of thought and being" (1876, 67). Lange's Neo-Kantianism,
by contrast, represents something like the best of both worlds, and so
promises a middle path in a seemingly intractable dispute. With
Duhring, Lange emphasizes the importance of grounding philosophy
in the results of the empirical sciences. But with Hartmann, he avoids
naively eliding the empirical objects studied by the sciences
with things in themselves.




It is not, however, only Lange's in-principle restriction of
knowledge to appearances that Vaihinger wishes to champion. More
importantly, he holds that Lange has demonstrated that the empirical
sciences *themselves* conclusively support the transcendental
idealist's position. In Chapter IV, Part 3 of the second volume
of his magnum opus *The History of Materialism and Critique of its
Contemporary Significance*, Lange draws on the work of Johannes
Muller and Helmholtz to argue that "the physiology of the
sense organs is the developed, or corrected Kantianism, and
Kant's system can, as it were, be viewed as a program for the
more recent discoveries in this field" (1873-75, 2:409).
The basic idea was that such research had shown that our perceptual
apparatus plays an active role in structuring our experience, and that
the output of such a process does not qualitatively resemble the
initial external stimulus, for which it is a mere "sign."
Since what we perceive is always the product of such unconscious
physiological processes, it supposedly follows that we have no
knowledge of the objects that ultimately cause our perceptions (for
more on these sorts of arguments, see [Hatfield 1990, 165-71,
195-208, and esp. 208-218; Beiser 2014, 199-205,
381-86], and the entries on Hermann von Helmholtz, and Friedrich
Lange). Thus, if Duhring rejects transcendental idealism, he
simply has not consistently followed his own prescription that
philosophy should base itself on the empirical sciences. And if
Hartmann claims to know the nature of things in themselves, he can do
so only by flagrantly ignoring the results of those sciences.




Though perhaps rhetorically effective, this argument leads to a basic
tension in Vaihinger's early view. Vaihinger sums up
Lange's conclusion as follows: "the result of the
physiology of the senses is that we do not ... perceive external
objects, but rather ourselves first *produce the appearance of such
things*, specifically as a consequence of the affection by
transcendent objects" (1876, 56). These appearances are the
result of our "physiological organization" operating on
sensory stimuli. But he goes on to concede that this
"'organization' signifies only the unknown ...
*Y* whose collaboration with the 'thing in itself',
*X*, produces the world of inner and outer experience" (1876,
57), that "even our own body ... is only a product of our
optical apparatus" (1876, 57), and that "not merely the
external
*world*, but also the *organs* with which we grasp it are
mere *images* of what truly exists, which itself remains unknown
to us" (1876, 58).




So, according to the Lange-Vaihinger view, the objects of our
experience are the joint product of affection by things in themselves
and the operations of our physiological organization. This is supposed
to have the conclusion that things in themselves are entirely
unknowable, *a fortiori* not knowable through the methods of the
empirical sciences. The problem becomes clear, then, when we ask what
sort of thing 'physiological organization' is supposed to
signify. If it refers to a thing in itself (the cognitive apparatus in
itself), then the empirical sciences could establish nothing about it.
In this case, the Langean argument is entirely impotent. If it refers
to an appearance, then there is evidently a circle in the argument: the
existence of appearances is supposed to be explained by the causal
collaboration of things in themselves and the perceptual apparatus, but
the perceptual apparatus is itself an appearance. Finally, if the
physiological organization is both an appearance and a thing in itself,
then the empirical sciences *can* in fact yield knowledge of at
least some things in themselves. This, of course, is precisely what the
argument is meant to forestall.




Vaihinger does little to assuage these problems in (1876). Sometimes
he suggests that they are rooted in the fact that the very notion of a
thing in itself involves a contradiction, albeit one which is
"grounded in the contradictory constitution of our cognitive
faculty itself" (1876, 34). In other words, Vaihinger seeks to
view the issue of things in themselves along the lines of a Kantian
antinomy--a conflict which arises necessarily from the nature of
our reason, but which can at least be recognized as such. This,
however, is of little help. For one, it is questionable whether the
basic epistemological standpoint of (1876) can even be coherently
stated without commitment to things in themselves. For another, a
crucial feature of Kant's antinomies is that they are
*resolved* by his transcendental idealism, thus lending that
doctrine an indirect proof (*KrV*, A 506/B 534). If the
critical philosophy itself were to generate insoluble contradictions,
that would be reason to reject, not accept, it. Vaihinger would
continue to struggle with these issues in the *PAO*, which
still aims to advance the broadly Langean project of naturalizing
Kantianism. As we shall see in SS6, however, Vaihinger's
conception of Kantianism undergoes a considerable shift, now taking
the form of what he calls "idealistic positivism",
"positivist idealism", or even (in what is evidently the
first use of the phrase) "logical positivism." For more on
Vaihinger's debt to Lange, see (Ceynowa 1993, 133-72;
Heidelberger 2014).


## 3. Interpretation of Kant




Before returning to Vaihinger's own positive philosophy, it is
worth examining the task that occupied him intensely between the
publication of (1876) and the *PAO*: the interpretation of
Kant. The rise of Neo-Kantianism in the second half of the nineteenth
century brought with it a renewed interest in the historical study of
the critical philosophy. The majority of the works written during this
period tended to approach Kant's texts polemically, either with
the aim of defending and "updating" them, or with the
intention of refuting them. In terms of its scholarly sobriety, depth
of textual analysis, and sensitivity to Kant's immediate
intellectual context, Vaihinger's *Commentary* was
unique. He notes that his approach will be that of those who analyze
ancient texts "with philological sobriety and strict rigor
... in order to determine their genuine meaning from
an *historical* standpoint" (1881-92, 1:iii). The
extent to which Vaihinger resists allowing his own philosophical
commitments to influence his interpretation is indeed impressive. In
fact, the very idea that understanding Kant's texts might
require a distinctively historical kind of approach seems to have been
something of a novelty and is among Vaihinger's lasting
contributions to Kant scholarship.




There are other important, and more substantive, respects in which the
*Commentary* was at the vanguard of Kant scholarship. The
dominant trend in the interpretation of Kant's theoretical
philosophy throughout most of the nineteenth century had been the
physio-psychological reading advanced by such figures as Schopenhauer,
Jakob Fries, Friedrich Beneke, Jurgen Bona Meyer, Helmholtz, and
of course Lange (Beiser 2018, 64-72, 81-84; 2014,
209-11, 460-63). According to this tradition, Kant's
main goal in the *Critique* was the discovery of the *causal
mechanisms* underlying perception. Kant's conception of the
*a priori* was accordingly understood as referring to innate or
ingrained properties of the psychological subject that played an active
role in the construction of perception and acquisition of empirical
knowledge. The first to break decisively with this tradition was
probably Hermann Cohen. Cohen (1871) highlighted the
*epistemological* side of Kant's project--his
interest in *justifying* various claims to knowledge.
Accordingly, Cohen interpreted the *a priori* as referring to
the logical, rather than psychological, conditions of knowledge (1871,
208). In this respect, Cohen's influence on the
*Commentary* was decisive. Vaihinger insists at the outset that
Kant's "philosophy is, in the first instance,
*epistemology* [*Erkenntnistheorie*]"
(1881-92, 1:8).




Vaihinger certainly does not, however, accept Cohen's
interpretation *tout court*. Though Cohen too had emphasized
the need for historical sensitivity in interpreting Kant, his aims
were ultimately still polemical: he believed more careful attention to
Kant's texts could exonerate his system from some of the
perennial charges of inconsistency. For example, Kant's doctrine
that things in themselves exist independently of us and causally
affect our minds to produce our representations had long been thought
to violate his doctrine that the categories have validity only for
objects of possible experience. Another charge, very much alive at the
time, was that Kant's key arguments for the
non-spatiotemporality of things in themselves failed on the grounds
that they showed, at best, only the subjectivity of space and time,
not their *mere* subjectivity. According to this criticism,
Kant overlooked the possibility that space and time might
be *both* subjective forms of intuition and objective
properties of things in themselves (the classic statement of this
criticism is [Trendelenburg 1867]). Cohen's response to both
charges was to argue that interpreters were wrong to read Kant's
doctrine of things in themselves as positing a class of entities
ontologically distinct from appearances. Instead, he maintained, the
Kantian thing in itself is a mere "limiting concept"
(*Grenzbegriff*), to whose actual existence Kant was never
committed (1871, 252, 268).




Vaihinger, by contrast, does not hesitate to admit that the above
objections are genuine problems for Kant. Indeed, he believes they
pinpoint serious inconsistencies in Kant's position. For
example, against Cohen's deflationary treatment of the thing in
itself, Vaihinger notes, "Kant speaks thousands of times of
affecting things in themselves; the impossibility of the existence and
causal efficacy of things in themselves is, by contrast, merely a
*consequence* that *Kant's readers* must certainly
draw from his theory of the categories, but which *Kant himself*
hints at only seldom, and even then only timidly" (1881-92,
2:47) (the actual target of this remark is Fichte, but the point
applies to Cohen's reading too). Vaihinger's goal in the
*Commentary* is not to exonerate Kant from such inconsistencies,
but to explain why he fell into them. In particular, Vaihinger argues
that careful attention to both Kant's pre-critical writings and
his unpublished notes reveals that the *Critique* is really a
"patchwork" of inconsistent views and arguments from
various periods of Kant's intellectual development. It consists
of "geological strata which differ in both time of composition
and content" (1902, 27). In the case of the Deduction, Vaihinger
even claims to have been able to trace precisely each portion of the
text to a particular series of notes from the decade between the
*Dissertation* and the *KrV* (1902). In this respect,
then, Kant's great book resembles more the texts of Homer than
the work of a single author, writing at a single time, with a single
set of views.




More specifically, Vaihinger believes the development of Kant's
thought proceeds through six stages. From 1750-1760 Kant is a
dogmatic rationalist after the Leibnizian-Wolffian model. Then, under
the influence of Locke and Hume, he endorses empiricism from
1760-1764. With the publication of *Dreams of a Spirit
Seer*, he begins to adopt the standpoint of the critical
philosophy, but by the time of the 1770 *Inaugural
Dissertation*, the influence of Leibniz (particularly of the
*Nouveaux Essais*) reasserts itself. This reversion to
dogmatism lasts until 1772 when he becomes a skeptic, again under the
influence of Hume. Finally, he arrives at the mature critical
standpoint with the publication of the *Critique of Pure
Reason* in 1781 (1881-92, 1:47-49). Unfortunately, on
Vaihinger's reading, doctrines from the first five periods
continue to figure in Kant's arguments for and even the core
tenets of the critical philosophy. It is this which explains the
numerous inconsistencies besetting Kant's system.




A clear example of Vaihinger's basic approach is his treatment
of Kant's famous argument for the subjectivity of space from
incongruent counterparts. In the *Prolegomena*, Kant argues
thus:



> 
> 
> 
> There are no inner differences here [in the case of incongruent
> counterparts] that any understanding could merely think; and yet the
> differences are inner as far as the senses teach ... one
> hand's glove cannot be used on the other... . These objects
> are surely not representations of things as they are in themselves,
> and
> *as the pure understanding would cognize them*, rather, they are
> sensory intuitions, i.e., appearances. (4:286)
> 
> 




Roughly, Vaihinger reconstructs the argument as follows: (1) Some
differences in the spatial properties of objects cannot be known
through the pure understanding; (2) All differences between things in
themselves can be known through the pure understanding; (C) Space is
not a thing in itself. Premise (2), however, violates Kant's
noumenal ignorance doctrine, according to which things in themselves
cannot be known through the understanding's categories. Thus,
Vaihinger concludes, "this assumption [that things in themselves
are knowable through the pure understanding] is obviously anathema to
Kantian criticism, and an archaic reversion to dogmatism"
(1881-92, 2:528). More specifically, his claim is that the
premise is residue from Kant's view in the 1770
*Dissertation*, according to which things in themselves
*are* objects as the pure understanding knows them
(1881-92, 2:354, 453, 522).




Vaihinger's reading of the *KrV*, and especially of the
Deduction, has become known as the "patchwork thesis." The
patchwork reading has been influential in Anglophone scholarship, due
largely to its adoption by Norman Kemp Smith (1918), but it remains
controversial. Since the reading apparently requires us to assume that
Kant failed to understand that combining views he knew were
inconsistent with one another would produce a view that is itself
inconsistent, it may be objected that, "if such a conclusion is
true, we must say that Immanuel Kant was either abnormally stupid, or
else that he took his thinking in a frivolous spirit" (Paton
1930, 157). However, the thesis that the Deduction, regardless of its
precise method of composition, at least contains multiple inconsistent
lines of argument, rather than a single unified argument, has found
able defenders since Vaihinger (see e.g., Wolff 1963; Guyer 1987). For a
recent challenge to this revised patchwork reading see (Allison
2015).




Vaihinger's interpretive work during the 1880's and
90's did not extend to the other major part of the *KrV*,
the Transcendental Dialectic. The *PAO*, however, includes a
supplementary appendix in which Vaihinger lays out a novel
interpretation of this chapter (*PAO* 201-35). The
Dialectic was the part of the *KrV* that clearly had the most
significant impact on Vaihinger's own thought, and his
interpretation of it is radical and interesting. It will therefore be
worth briefly examining before turning to the main argument of the
*PAO*. 




In the Dialectic, Kant claims that certain concepts (e.g., those of an
immaterial soul, freedom of the will, and God) have their root in pure
reason. He argues that such concepts are mere "Ideas"
(*Ideen*), in the sense that they are not constitutive
principles of experience, and thus yield no "cognition"
(*Erkenntnis*) of objects. Nevertheless, he suggests they are
"not arbitrarily thought up" (A 327/B 384), but have a
number of important "regulative" uses. In his works on
moral philosophy, Kant goes on to argue that we can even have a
certain kind of "practical cognition" of or
"rational faith" in the Ideas. A natural interpretation of
Kant's position regarding the Ideas holds that we lack
theoretical justification for believing that they refer to objects,
and this lack of justification is such that we cannot claim knowledge
of the existence or non-existence of such objects. Practical reason,
however, may provide justification for the belief in (say) the
existence of God, even if not of a sort sufficient to yield knowledge
of him. Vaihinger disputes this reading. Instead, he interprets the
Ideas as self-conscious fictions, which are nevertheless licensed by
their theoretical and practical utility. This utility justifies us in
"making use" of such concepts--looking, e.g., at
nature as though it were the product of an intelligent
designer--but never in *believing* they refer to objects.
The interpretation relies crucially on two factors: first, a
suggestive passage in which Kant calls Ideas "heuristic
fictions" (A 771/B 799), and contrasts them with hypotheses; and
second, Kant's frequent use of '*als ob*' and
related locutions when describing the regulative employment of the
Ideas. Both the distinction between fictions and hypotheses, and the
idea of treating reality *as if* certain concepts appropriately
applied to it are major themes that find extensive development in the
*PAO*.




Vaihinger's interpretation of the Ideas as fictions is highly
controversial, and was already subjected to withering criticism in his
own day by Erich Adickes (1927). Adickes accuses Vaihinger of ignoring
countless passages that flatly contradict his fictionalist reading,
and of misleadingly paraphrasing or eliding passages he does cite. In
one way, at least, this criticism is unfair. Vaihinger explicitly
concedes: "in Kant we also find in the same contexts many
passages which permit or even demand a contrary interpretation...
. Two tendencies are revealed, a critical and a dogmatic, a
revolutionary and a conservative" (*PAO*
212). Vaihinger's interpretation is not, unlike his work in
the *Commentary*, intended to be strictly historical; he is
rather presenting one strand in Kant's thought that he finds
especially promising. Adickes nevertheless makes a compelling case
that even those passages on which Vaihinger does rely do not speak
decisively in favor of his interpretation. Most contemporary Kant
scholars follow Adickes in rejecting the fictionalist interpretation
of the Ideas, though it continues to find some supporters (see e.g.,
Shaper 1966; Korsgaard 1996, 162-76; and esp. Rauscher
2015). 


## 4. The Epistemology of the *PAO*




I turn now to Vaihinger's chief systematic work, the
*PAO*. That this work represents his attempt to continue
Lange's project of naturalizing Kantian epistemology
(Heidelberger 2014, 51-55) may appear surprising given
Vaihinger's interpretation of Kant. Confusion here may be
forestalled by attending to something Vaihinger himself says about the
aim of the work:



> 
> 
> 
> There were two possible ways of working out the Neo-Kantianism of
> F.A. Lange. Either the Kantian standpoint could be developed, on the
> basis of a closer and more accurate study of Kant's teaching, and
> this is what Cohen has done, or one could bring Lange's
> Neo-Kantianism into relation with empiricism and positivism. This has
> been done in my philosophy of "As if," which also leads to
> a more thorough study of Kant's "As if" theory.
> (*PAO* xxii)
> 
> 




So Vaihinger distinguishes between the views maintained by the
*historical* Kant, and Lange's brand of
*Kantianism*, which his own systematic work defends and
develops.




But, the *PAO* also builds on Lange's position in
non-trivial ways. Vaihinger's autobiographical essay "The
Origin of the Philosophy of 'As If'" points to two
further significant influences, Arthur Schopenhauer and Charles Darwin.
Vaihinger's interest in Schopenhauer was sparked by the doctrine
that the intellect is "a mere tool in the service of the
will" (Schopenhauer 1958, 2:205). This view is based in part on
Schopenhauer's metaphysics, according to which the ultimate
nature of reality is nothing other than a suprapersonal, aimless,
quasi-volitional striving or "will." Schopenhauer holds
that this "will" expresses itself empirically in the
striving of organic beings to preserve their individual existence, and
the intellect has accordingly developed as a mere tool to aid more
complex organisms in this task. Vaihinger believed that Darwin's
theory of natural selection had provided an empirical grounding for
Schopenhauer's hypothesis (*PAO* xviii). This was crucial,
since Vaihinger's own Kantianism prevented him from endorsing
Schopenhauer's speculative vitalist metaphysics (*PAO*
xvii). At the same time, Vaihinger comes to view Kant's doctrine
of the essential limits of our cognition through this
Schopenhauerian-Darwinian lens: the "limitations of human
knowledge," he says, are "a necessary and natural result of
the fact that thought and knowledge are originally only a means, to
attain the Life-purpose, so that their actual independence signifies a
breaking-away from their original purpose; indeed, by the fact of this
breaking-loose, thought is confronted by impossible problems"
(*PAO* xviii). Vaihinger will use this idea to motivate his own
fictionalism, and to provide a radical reinterpretation of
Kantianism.




These various influences are drawn together in the introductory
chapters of *PAO*. Here, Vaihinger presents a view of the
"psyche" as a purely natural faculty, akin to a bodily
organ, and bound by the same laws as the rest of the organic world. All
psychic activities, including "scientific thought," are
"to be considered from the point of view of an organic
function" (*PAO* 1). Like bodily organs, the psyche is
designed (or rather, selected) to perform a particular role within the
total economy of the organism. Its purpose is "to change and
elaborate the perceptual material into those ideas, associations of
ideas, and conceptual constructs," which produce "a world
[in which] objective happenings can be calculated and our behavior
successfully carried out in relation to phenomena"(*PAO*
2). Its purpose is therefore not "to be a copy [*Abbild*]
of reality," but rather "an *instrument for finding our
way about more easily in this world*" (*PAO* 22,
translation altered). Though broadly in the spirit of Schopenhauer and
Darwin, this instrumentalist conception of the mind is, as Ceynowa has
argued (1993, 35-132), also more specifically indebted to the
nineteenth century psychologist Adolf Horwicz.




Whatever its exact provenance, Vaihinger's basic thought is that
what is selected for in the evolution of our cognitive capacities is
the ability to aid us in carrying out activities that are useful for
the purposes of survival. Specifically, Vaihinger seems to reason that
any course of action--say, procuring food for
oneself--involves at least some minimal degree of planning, and
that in turn requires some basic ability to predict what the future
will be like, and to know how it will be different if we choose to
ph rather than to ps. Thus, he suggests that the purpose of
thought is "*to calculate those events that occur without our
intervention* and to realize our impulses appropriately"
(*PAO* 3). For the bare purposes of carrying out those actions
necessary for survival, Vaihinger is claiming, the intellect would not
have to be a reliable guide to the way the world really is. On the
contrary, fictions may have an indispensable role to play here.




What are we to make of this sort of argument? One might suggest that
the fact that our cognitive apparatus is a product of natural selection
supports, rather than undermines, the idea that it is a reliable guide
to the way the world is. For, being mistaken about how things stand in
one's environment is surely an impediment, not an aid, to
survival. Vaihinger would likely respond that this only shows that we
have to get the *right* things about the world right. It does
not mean that our total image of the world is, or even could be, a
*copy* of reality, accurate in all its details.
Vaihinger's view is that the picture of the world that is easiest
to work with will depart from reality in certain crucial respects.




One may now wonder, however, what is to be made of Vaihinger's
near exclusive emphasis in *PAO* on fictions in the natural
sciences and mathematics. After all, the theorizing in fundamental
physics is a rather different matter than determining how to find a
meal, and even if such theories turn out to be useful down the line, it
seems that life would (and does) manage just fine without them. Here,
Vaihinger relies on another Darwinian idea, which he calls the
"Law of Preponderance of the Means over the End," according
to which "means which serve a purpose often undergo a more
complete development than is necessary for the attainment of their
purpose" (*PAO* xxix). In the language of contemporary
evolutionary biology, scientific thought is like a
"spandrel." At the same time, Vaihinger is keen to
emphasize the connection between scientific theorizing and more humdrum
cognitive processes. He adopts the broadly Kantian view that what is
given to us in experience is merely a "chaos of sensations"
(*PAO* 117), which needs to be ordered and refined by the
logical functions of thought, or categories. For example, the repeated
co-occurrence of sensations of a branching shape and sensations of
green leads the psyche to postulate a relation of substantial inherence
between a *thing* or *substance* (the tree) and its
*attribute* (green) (*PAO* 122-23). However, he
argues in a manner evocative of Berkeley, the notion of a substance is
incoherent since it implies the existence of a bare substrate with no
properties whatsoever (*PAO* 125-26). The fiction is
nevertheless justified, he suggests, because it facilitates the
recognition of regularities in the occurrences of our sensations, and
the communication of these regularities to others (*PAO* 130).
Given that our most immediate relation to the world is thus mediated by
the categories (which also include the relations of part-whole,
cause-effect, *inter alia*), it is natural to suppose that these
fictions will resurface in our more sophisticated theories, e.g., in the
form of the atom (a simple material substance). Vaihinger is not
suggesting that genuine knowledge that serves no particular practical
aim is impossible; but he is suggesting that our total theoretic image
of the world is ultimately limited by those fictions that have been
preserved as most adaptive for our basic practical aims (*PAO*
130).




Vaihinger's emphasis on the deep connection between cognition
and action have led many interpreters to liken his views to those of
the American pragmatists (e.g., Appiah 2017, 4; Koridze 2014; Fine
1993, 4; and esp. Ceynowa 1993). Others have disputed this connection
(Bouriau 2016). Vaihinger himself tells us that fictionalism and
pragmatism share important similarities, but nevertheless are
distinguished by the fact that pragmatism accepts, whereas
fictionalism rejects, the principle that "an idea which is found
to be useful in practice proves thereby that it is also true in
theory" (*PAO* viii). So, if one defines a pragmatist
narrowly as someone who endorses this Jamesian definition of truth,
Vaihinger is no pragmatist; his core contention is that "we may
not argue from the utility of a psychical and logical construct that
it is right" (*PAO* 51). Nevertheless, given
Vaihinger's emphasis on the inseparability of practical and
theoretical thought, his view that the use of a concept can be
justified on purely practical grounds, and so forth, it does not seem
unfair to liken him to the pragmatist tradition in a wider sense. 


## 5. The Nature of Vaihinger's Fictionalism




Central to Vaihinger's project in the *PAO* is a
distinction between two sorts of fictions: (1) what he (somewhat
inaptly) terms 'semi-fictions,' which are "methods
and concepts based upon a simple deviation from reality"
(*PAO* 59); and (2) 'real' or 'genuine
fictions' which are *self-contradictory* concepts
(ibid.). In other words, semi-fictions are statements or propositions
that happen not to correspond to the world; genuine fictions are those
that claim something *impossible* about the world.




An important example the first kind is what Vaihinger calls the
"abstractive" or "neglective" fiction
(*PAO*, 14-17, 140-41). Such fictions are roughly
what we have in mind today when we speak of 'idealized
models' (contemporary philosophers of science sometimes
distinguish further between "Aristotelian" and
"Galilean" methods of idealization. See the article on
Models in Science. Vaihinger does not clearly distinguish these). A
standard example is the model of the planetary system given in
classical mechanics:



> 
> 
> 
> In physics we find such a fiction in the fact that masses of
> undeniable extension, e.g., the sun and the earth, in connection with
> the derivation of certain basic concepts of mechanics and the
> calculation of their reciprocal attraction are reduced to points or
> concentrated into points (gravitational points) in order, by means of
> this fiction, to facilitate the presentation of the more composite
> phenomena. Such a neglect of elements is especially resorted to where
> a very small factor is assumed to be zero. (*PAO* 
> 16)
> 
> 




The idea is familiar. If what we are interested in is determining
the trajectory and velocity of the planets around the Sun, then it is
useful to ignore or iron-out a wide variety of features of the system,
e.g., the size of the planets, the presence of friction, the
gravitational pull that the planets and their moons exert on one
another. Here, then, we evidently have a clear-cut case in which
"pretending" that certain things are true of the solar
system can greatly aid our aim of prediction. As Vaihinger notes, we
get the "right" results here because the properties of the
system we are ignoring have only a negligible influence on the
phenomena we are interested in studying. The solar system behaves
*nearly* *just as it would* if the planets *were*
mass points, etc. This suggests a counterfactual understanding of
fictions: by reasoning from assumptions that are false--sometimes
radically false--at the actual world, we may still arrive at
conclusions that are true, or quite nearly true, at the actual world.
If those results are arrived at more efficiently by entertaining the
fiction, then the fiction is justified.




If this is Vaihinger's view, however, it would appear to face a
serious difficulty. For, his main interest is in the so-called
"real fictions," which, as noted above, are not merely
false, but *contradictory*. Since everything follows from a
contradiction, any counterfactual whose antecedent is a real fiction
will be trivially true, and this is to say they cannot possibly do the
work Vaihinger envisions (Appiah 2017, 11; Cohen 1923, 485). One way to
respond, here, is to note that the logic with which Vaihinger operates
is still essentially the version of Aristotelian logic found in Kant
and throughout much of the nineteenth century. Such
pre-twentieth-century logics often implicitly reject the principle
*ex contradictione quodlibet*. See, e.g., the discussion of
conditionals in the influential *Port-Royal Logic* (Arnauld and
Nicole 1996, 100).




Relatedly, but from a more contemporary perspective, one might read
Vaihinger as anticipating some recent views on counterpossible
reasoning (Pollard 2010). Consider the following counterfactual
conditionals:


* (1)
If Fermat's last theorem were false, then
 no argument for it would be sound.
* (2)
If Fermat's last theorem were false, then
 Andrew Wiles would deserve eternal fame.
* (3)
If intuitionistic logic were correct, then the Law
 of Excluded Middle would fail.
* (4)
If intuitionistic logic were correct, then the Law
 of Excluded Middle would hold.




Intuitively, (1) and (3) are true while (2) and (4) are false.
Moreover, someone who rejects intuitionism might well wish to
*argue* against intuitionism by relying on something like (3),
even though what the antecedent states is, by her lights, impossible.
These facts have led some to suppose that (1) and (3) are not merely
true, but non-trivially true (for more on these sorts of arguments, see
the entry for Impossible Worlds). Vaihinger's fictionalism might
thus be read as adding a heap of substantive examples to the list of
alleged non-trivial counterpossible conditionals.




This sort of reading seems supported by examples that Vaihinger
himself gives, and the theory of "fictive judgments" he
bases on them. One of Vaihinger's favorite examples is:


* (5)
If the circle were a polygon, then it would be
 subject to the laws of rectilinear figures. (*PAO*,
 193)




Though (5)'s antecedent and consequent both state something
impossible, Vaihinger contends it forms the basis of
Archimedes's proof of the area of a circle using the method of
exhaustion (*PAO* 177). Here, then, is a case in which a proof
no one would wish to call trivial allegedly proceeds from a
contradictory assumption. Generalizing, Vaihinger claims, "in a
hypothetical connection [sc. conditional proposition], not only real
and possible but also unreal and impossible things can be introduced,
because it is merely the connection between the two presuppositions
and not their actual reality that is being expressed"
(*PAO* 193-94).




Anthony Appiah rejects this kind of interpretation, on the grounds
that such counterpossibles are unintelligible (2017, 11-17; cf.
Wilholt 2014, 112). Instead, he suggests Vaihinger's talk of
useful contradictions is more fruitfully understood as referring to
the use of multiple mutually incompatible models. In particular, the
point is that we may find it useful to regard certain phenomena in one
way for some purposes, but in another, incompatible way for other
purposes. Even when it turns out to be useful to combine incompatible
models for understanding one and the same phenomenon (or range of
phenomena), Appiah suggests, Vaihinger need not be committed to a
paraconsistent logic. Rather, drawing on (Cartwright 1999), he
suggests that using a model does not involve drawing out each of its
logical implications, but instead a kind of skill of "knowing
which lines of inference one should and which one should not
follow" (2017, 13). Moreover, because our main aim in using
models is not ultimately to obtain the truth about the physical world,
but to get around in it, there is no reason to avoid such
inconsistency (2017, 14-17).




Appiah's interpretation allows those who are wary of
paraconsistent logics to salvage something philosophically promising
from Vaihinger's talk of contradictions. It also perhaps has the
advantage of doing greater justice to the multifarious character of
Vaihinger's theory of fictions. For, while Vaihinger claims that
the fictive judgment has a "hypothetical element," he does
not simply reduce fictive judgments to conditionals (*PAO*
194). On the other hand, the interpretation stumbles against texts in
which Vaihinger suggests that the contradictions of real fictions
exist
*within* theories or models, not between them. For example, the
concept of a (classical) atom is supposed to be a real fiction because
it is absurd to suppose something which occupies space, but
nevertheless has no extension. This is to say that the atomistic
fiction is itself contradictory, not merely that it conflicts with
other ways of modeling matter. Another way of putting the worry is to
note that the interpretation blurs the apparently sharp distinction
between semi-fictions and real fictions: any model will be a real
fiction as long as we use it together with another model incompatible
with it.




For yet another approach, which denies that Vaihinger has or needs a
general account of how contradictory fictions can be fruitful, see
(Fine 1993, 9-11). On this reading, Vaihinger is interested only
in surveying actual scientific practice, and revealing that, as a
matter of fact, it *does* make fruitful use of real fictions;
the question of how this is possible is beside the point. There is
something to this characterization of Vaihinger's procedure,
which trades more in examples than in general pronouncements. However,
it will also be difficult for proponents of this reading to explain
passages like these: "This purpose [of thought] can only be that
of facilitating conceptual activity, of effecting a safe and rapid
connection of sensations. What we have to show, therefore, is
*how* fictional methods and constructs *render this
possible*" (*PAO* 52, emphasis added); "the
philosophy of as if shows that *and why* these false and
contradictory representations are still useful" (1921a, 532,
emphasis added). Here, Vaihinger seems to indicate that his purpose is
not just to enumerate instances of useful fictions, but to explain how
and why they are useful.




In addition to Vaihinger's specific analysis of fictions, one
might wonder about his precise brand of fictionalism. Contemporary
philosophers distinguish between "hermeneutic
fictionalism" and "revolutionary fictionalism" (see
the entry on Fictionalism). Hermeneutic fictionalism holds that
certain domains of discourse *are* fictional, in the sense that
their participants are not aiming at literal truth, but only seeming
to do so. Some textual evidence speaks in favor of reading Vaihinger
as a hermeneutic fictionalist. For example, he writes: "the
axiom and the hypothesis ... endeavor to be expressions of
reality. The fiction, on the other hand, is not such an expression nor
does it claim to be one" (*PAO* 60). And
Vaihinger's theory of the fictive judgment maintains that many
judgements of the syntactic form '*A* is *B*' are
properly analyzed as, or merely elliptical for, '*A* is to be
regarded *as if* it were *B*'--"the
'is' is a very short abbreviation for an exceedingly
complicated train of thought" (*PAO* 195). On the other
hand, in many places Vaihinger clearly indicates that he thinks we
often treat what would be better regarded as fictional discourse as
aiming at truth. Many disputes, he suggests, can be resolved by
reinterpreting such discourse fictionally. Thus, for example,
proponents of classical atomism have been wrong to think that their
theory is true, but their opponents have also been wrong to believe
that the theory should therefore be given up (*PAO* 53). He
makes an analogous point about the dispute between substantivalists
and relationalists over the nature of space (*PAO*
170-71). So, Vaihinger appears to be a revolutionary
fictionalist at least about some discourses in which he is
interested.


## 6. The As-If Philosophy and Kantianism




The most obvious aim of the *PAO* is to establish the
centrality of fictions to our cognitive life. But there is also a
broader, and in some ways more ambitious, aim to the book--to
provide the kind of "corrected Kantianism" Lange had tried
to establish in the *History of Materialism*. As we saw above,
Vaihinger views Kant's system as riddled with inconsistencies,
which arise from the alleged fact that Kant retains certain elements
of his pre-critical dogmatism even after adopting the critical
standpoint. The As-If philosophy can be seen as an attempt to retain
what Vaihinger takes to be Kant's core philosophical insights,
while removing the inconsistencies that beset the surrounding system
in which those insights were originally couched. 




As was noted above, a major problem for Vaihinger's early view,
as for many of the Neo-Kantians of his day, was the status of the thing
in itself. Vaihinger now consistently rejects this notion, predictably
labelling it a fiction. Given that things in themselves are supposed to
be transcendent *substances* that *causally*
*affect* us, this rejection follows immediately from his view
that the concepts of substance and cause are themselves fictions
(*PAO* 55-56). True to form, however, Vaihinger still
holds that the concept of things in themselves has some utility: as
Cohen had argued, it serves as a "limiting concept"
(*PAO* 55), ensuring that we restrict our inquiries to what is
empirically given to us. As we have seen, Vaihinger puts an
instrumentalist spin on this Kantian idea; all knowledge is empirical
in the sense that our guiding cognitive aim is the prediction and
control of empirical phenomena, not correspondence to objective reality
(though, once again, it bears emphasizing that Vaihinger does not seem
to be claiming that such correspondence is impossible, only that it is
incidental to our main epistemic aim).




Vaihinger's rejection of the thing in itself is implicit in
the general label he gives to his own philosophical view,
"idealistic positivism." The 'positivism' here
is in part an epistemological, and in part a metaphysical thesis. The
epistemological thesis is that "what is given consists only of
sensations" (*PAO* 124; cf. xxviii). The metaphysical
thesis is that "what we usually term reality *consists* of
our sensational contents [*Empfindungsinhalte*]"
(*PAO* xxx, emphasis added); "Nothing *exists*
except sensations" (*PAO* 44, emphasis added; cf. 1921a,
532-33). This extreme view (for which Vaihinger does not argue)
has the immediate conclusion that all knowledge is of appearances,
since nothing exists except appearances.




In addition to this radical kind of empiricism, the *PAO*
continues to uphold the broadly Kantian view that cognition is
necessarily *limited*, or, as Vaihinger sometimes puts it, that
there is no "identity between thought and being." However,
it is no longer limited in the sense of being cut off from some
transcendent realm of things in themselves, but in being essentially
incomplete. The point is best appreciated by attending to another
distinction central to the *PAO*--that between
*fictions* and *hypotheses*. Hypotheses (not to be
confused with so-called "hypothetical judgments") are
judgments that are "problematic" in form, i.e., which have
the form 'it is possible that *A* is *B*'
(where the relevant sense of possibility is epistemic). Thus, if the
judgment 'matter is composed of atoms' is a hypothesis,
the person making it is maintaining that it may be true, and holds out
hope that it may be confirmed or falsified in the future. By contrast,
and as we have seen already, the fictive judgment has the form
'*A* is to be regarded *as if* it were *B*
(when in fact *A* is *not B*).' Since Vaihinger
holds that such judgments can be licensed by their practical utility,
and because it is our practical aims that ultimately guide and
constrain theoretical inquiry, Vaihinger infers that every theory will
necessarily involve some fictions; not even the best theory will
consist entirely of hypotheses, much less true hypotheses.




The distinction between hypotheses and fictions is important for
understanding Vaihinger's revised brand of Kantianism in another
way as well. In the Dialectic, Kant had argued that dogmatic
metaphysics necessarily leads reason into a series of conflicts, or
"antinomies," with itself. It can produce, that is,
equally valid arguments putatively establishing both that freedom
exists and that freedom does not exist, that matter is composed of
simples and that matter is not composed of simples, and so on. Kant
claims that these conflicts are "natural" to reason, since
reason has an innate drive to know the "unconditioned." He
argues, however, that these conflicts can be avoided if (and only if)
one recognizes the non-spatiotemporality of things in themselves.
Transcendental idealism allows us to maintain that in some of the
antinomial conflicts it is possible for both the thesis and antithesis
to be false without contradiction, and that in others it is possible
for both to be true without contradiction. The critical philosophy
thus has the distinct advantage of being able to explain how certain
apparently insoluble metaphysical debates arise, and of providing the
only possible resolution of those debates. Vaihinger similarly posits
a natural human tendency to confuse, not appearances and things in
themselves, but fictions and hypotheses. Many statements that are
introduced into our discourse as fictions end up being taken for
hypotheses. And vice versa, many propositions that are originally
intended as hypotheses are retained with mere fictional significance.
Vaihinger calls this the "law of ideational shifts"
(*Gesetz der Ideenverschiebung*) (*PAO* 92-99).
Seemingly intractable debates in the sciences can be resolved, he
maintains, by systematically recognizing this distinction. Thus, for
instance, certain arguments against atomism are cogent if intended to
establish that atomism is false (since it is *contradictory*);
but they are erroneous if intended to imply that atomism should be
rejected. Likewise, arguments for atomism are sure to fail if they are
meant to establish the existence of atoms; but they are perfectly
acceptable if they only aim to show that atomistic discourse is useful
and indeed essential for scientific practice. For, the atomist's
discourse is best understood as a conscious fiction. As Vaihinger
suggests, the confusion arises from ignoring the essential practical
dimension of thought (*PAO* xviii).




How successful is Vaihinger in resolving the alleged tensions in
Kant's critical philosophy? On one level, straightforwardly
rejecting things in themselves and endorsing an ontology only of
sensations clearly avoids the supposed problem of attributing causal
efficacy to transcendent objects. On another, however, it would appear
that Vaihinger cannot so easily reject things in themselves without
causing problems for his basic epistemological view. For one, an
obvious question arises as to *what it is* that *has*
the sensational contents that serve as Vaihinger's ontological
basics. For another, we have seen that Vaihinger's arguments in
the Introduction hold that the *mind* or
"*psyche*" operates on sensory stimuli, and that it
has certain ends to which fictions are expedient means. If nothing
exists except sensations, then it seems we must read Vaihinger's
talk of 'mind' loosely, perhaps as referring to some
particular kind of collection of or relation between sensations. But,
one is tempted to say, it is simply incoherent to suggest that
sensations themselves are the bearers of sensations, that they have
aims, that they operate on and systematize other sensations, etc. At
the very least, "operation" would seem to be a causal
notion, so that Vaihinger's causal fictionalism threatens to
undermine the arguments at the foundation of his system. Vaihinger
sometimes attempts to respond to these sorts of worries. He suggests,
for example, "From our point of view the sequence of sensations
constitutes ultimate reality, and two poles are mentally added,
subject and object" (*PAO* 56); "nothing exists
except sensations which we analyze into two poles, subject and
object ... . In other words, the ego and the
'thing in itself' are fictions" (*PAO*
44). The question of course is who the *we* is here that is
doing the *mental adding*. Perhaps Vaihinger intends such talk
to itself be fictional. But he cannot hold that without undermining
the very motivation for his fictionalism. Nor does Vaihinger ever make
clear and precise exactly what "poles" of sensations are
supposed to be.




One may also worry that, throughout the *PAO*, Vaihinger has
reverted to a crudely psychologistic version of Kantianism that both
he and Cohen had earlier rejected. On this score, Vaihinger is more
easily defended. Though his fictionalism draws on certain biological
and psychological theories, his main concern is still epistemological:
"Apart from the general warning not to confuse fictions with
reality, we may also call attention to the fact that every fiction
must be able to justify itself, i.e., must *justify* itself by
what it accomplishes for the progress of science" (*PAO*
79). There would arguably be a confusion if Vaihinger held that the
fact that certain concepts (or dispositions to form them) are
psychologically innate justifies us in *believing* that there
exist objects exemplifying them. But that is precisely the view he
wishes to reject. The appeal to the theory of natural selection is
intended to suggest a *pragmatic*, rather than evidential,
justification for the *use* of those concepts. In this sense,
Vaihinger sees himself as drawing on Kant's method of justifying
the concepts of God, freedom, and immortality on practical grounds,
but extending it beyond the domain of moral philosophy.