A.1 -
Biographical Misconceptions
At the very beginning of writing the
book, I did not wish to include this appendix, but I was very surprised
to see how very well rooted are the myths against Edmund Husserl, and
how deep the rejection of his doctrine in the analytic tradition has
been.
157
My use of Husserl's philosophy of logic
and mathematics as a starting point to clarify the relation between
formal sciences and natural sciences would surprise many philosophers.
Most analytic philosophers completely ignore Husserl's philosophy of
mathematics, even if it is, perhaps, the one that best describes
mathematics in the twenty-first century. Even in the case of
mathematicians, they regard Gottlob Frege as being far superior to
Edmund Husserl and much more worthy of recognition.
I want to explain briefly why this is so
in the analytic world. First, there is an unfounded myth that began
with Dagfinn Føllesdal's master's thesis:
Husserl and Frege: A
Contribution to Elucidating the Origins of Phenomenological Philosophy
and his article “Husserl's Notion of Noema”, where he says that at
first Husserl began favoring psychologism, and from that perspective he
wrote his
Philosophy of
Arithmetic (1891). Later, he changed his mind due to
Frege's review against this work (Frege, 1894/1972). The myth further
states that Husserl became a kind of fregean semanticist and that his
phenomenological notions (like the notions of
noema and object (
Gegenstand)) are
nothing more than an extension of the fregean distinction between sense
(
Sinn) and
referent (
Bedeutung).
And as if that were not enough, many other authors accuse Husserl of
falling into the claws of psychologism once again.
None of this is true. As it turns out,
apparently Frege's review of Husserl's
Philosophy of Arithmetic
had nothing to do with him changing his mind. As some studies have
shown, some of Frege's criticisms were valid, but others were not. He
exaggerated Husserl's position to the point of caricaturing it. Many
authors consider Frege's criticism against Husserl's notion of
abstraction as accurate, when in reality Husserl did not favor the
silly assertions Frege accused him of saying.
158
It is
possible that Frege's attack was not directed exclusively to Husserl,
but to Georg Cantor, who was Husserl's close friend, colleague, and
mentor, who, like Husserl, was also a disciple of the renowned
mathematician Karl Weierstrass, whom Frege opposed.
159
Frege
would charge Cantor exactly with the same errors he charged Husserl
with.
160
The myth that Husserl adopted fregean
semantics after the famous fregean review (1894) is also false. Husserl
already had his own theory of sense (meaning) and referent
(objectuality) by 1890. We can accept that Philosophy of Arithmetic was
published in 1891, but that only means it was published that year. He
finished writing it in 1890. So,
Philosophy
of Arithmetic represents his thinking on mathematics up to
1890. J. N. Mohanty also offers this information:
the basic change in
Husserl's mode of thinking which by itself could have led to the
Prolegomena conception of pure logic had already taken place by 1891.
[. . .] If pure logic is defined in the Prolegomena in terms of the
concept of ideal objective meanings, then already the 1891 review of
Schröder's work contains this concept. If the major burden of Frege's
1894 review of [
Philosophy
of Arithmetic] is the lack of distinction, in that work,
between the subjective and the objective, between
Vorstellung and
Begriff, then
Husserl already had come to distinguish between
Vorstellung meaning
and object in his 1891 review.
161
It was Frege, in a letter addressed to
Husserl (May 24, 1891), who recognized that he made a distinction
between sense and referent, and he (Frege) compares correctly both
theories of sense and referent of concept words. Husserl himself
recognized that by the time
Philosophy
of Arithmetic was published, he already disagreed with its
content. He says that he began having doubts about psychologism from
the very beginning. He attributes his change from psychologism to his
reading of Gottfried Wilhelm von Leibniz, Bernard Bolzano, Rudolf
Hermann Lotze, and David Hume. He makes no mention of Frege as being
decisive for the change.
162 In fact, in his
Logical Investigations
Husserl mentions Frege only twice: the first one in a footnote to point
out that he retracted three pages of his criticism of Frege's
The Foundations of Arithmetic,
163
and the other one to question his use of the word “
Bedeutung” to
denote referent rather than meaning (sense).
164
Finally, contrary to what many people
think, Husserl did not fall again into psychologism. He maintained
basically the core of the criticism against psychologism made in the
“Prolegomena” throughout his life, and we can find some of them in
works as late as
Formal
and Transcendental Logic (1929). That accusation usually
is the product of a misunderstanding between husserlian semantics and
his phenomenological doctrine. But even the ideal realm plays
a very important role in phenomenology,
noemata are the
irreal (ideal) necessary correlates of real noetic acts of
consciousness.
Another reason why some philosophers do
not know about Husserl's doctrine of formal sciences has to do with the
fact that many phenomenologists have not paid attention at all to it,
either because they do not know it, or because they are not acquainted
enough with logic and mathematics to notice it. They mostly focus on
Husserl's phenomenological doctrine in general as well as his doctrine
of the crisis of the European sciences.
There are also those husserlian scholars
who make some distorted expositions of Husserl's philosophy of
mathematics. For example, some authorities in this area give the
impression that Husserl said that using eidetic intuition and eidetic
variation we are able to abstract numbers, sets, etc. This is false.
For Husserl, as we have seen in Chapter 2, numbers and sets are
constituted by consciousness through categorial intuition. I do agree
with Rosado (1997) that not to mention categorial intuition in
Husserl's philosophy of mathematics would be like trying to explain
newtonian mechanics without mentioning the three laws of motion.
165
Others confuse categorial intuition and eidetic intuition, leading to
confusing notions of state-of-affairs and situation-of-affairs,
therefore, unable to understand mathematical intuition as being
categorial intuition and categorial abstraction.
166
Up to now, we have presented most of the
reasons why people have dismissed Husserl's philosophy of logic and
mathematics. So, to finish exorcising some philosophers' image of
Husserl, I will present his background in mathematics and philosophy of
mathematics.
1. While Husserl was a student at the University of Berlin,
he studied with great mathematicians such as Leopold Kronecker and Karl
Weierstrass (1878-1881). Later, Husserl became Weierstrass' assistant
(1883-1884).
167
2. After being Franz Brentano's disciple (1884-1886), he went
to the University of Halle, where he was under the supervision of Carl
Stumpf, who was also Brentano's disciple and to whom Husserl later
dedicated his Logical Investigations. Claire Ortiz Hill points out that
it was through Carl Stumpf that he increasingly became interested in
platonic ideas and led him away from Brentano's philosophy.
168 Stumpf
was the one who convinced Gottlob Frege to elaborate a philosophy to
clear up the purpose of his recently created conceptual notation (
Begriffsschrift),
which led Frege to write his philosophical masterpiece
The Foundations of Arithmetic.
169
3. It was during his years in Halle where he befriended Georg
Cantor, the father of set theory, who would become his mentor
(1886-1901).
170
4. Husserl's first philosophical works were precisely about
mathematics. In Halle, he presented his professorship doctoral
dissertation
On the
Concept of Number about the psychological origins of sets
and numbers, and later in 1891 he published his
Philosophy of Arithmetic:
Psychological and Logical
Investigations. We also have to take into account the
first volume of
Logical
Investigations titled “Prolegomena of Pure Logic” where
Husserl exposes his definitive doctrine on logic and mathematics. In
all of these works he was concerned about logic and mathematics, and he
wanted to develop a proper epistemology.
5. He revealed Franz Brentano in 1892 that he had already
concluded that non-euclidean geometry was as legitimate as euclidean
geometry. For him, space does not need to be euclidean space to be
consistent, and that there could be many other
a priori possible
spaces. This happened years before the general theory of relativity
legitimized the use of non-euclidean geometry in natural science.
171
6. Later, when Husserl went to the University of Götingen, he
was a colleague of David Hilbert, the great mathematician who was
looking for a definitive proof of the completeness of mathematics. He
also believed in such completeness, and formed part of Hilbert's Circle
(1901-1916).
172
7. Husserl was deeply interested in the paradoxes of set
theory. Ernst Zermelo, a mathematician known for his works on set
theory, was Husserl's friend. Zermelo found a paradox and in 1902
communicated it to Husserl and Hilbert. The reason for this is that
Husserl had discussed a similar paradox in a review he wrote in 1891.
Bertrand Russell also found this very same paradox and told Frege that
his logical foundation of arithmetic as presented in
Basic Laws of Arithmetic
made this paradox possible. This is the reason why the world knows it
as the “Russell Paradox”, even though Zermelo found it first. Here we
will call it the “Zermelo-Russell Paradox”. Many of Husserl's works on
set paradoxes (which are hundreds of pages) still remain unpublished.
173
8. Even in later works such as
Formal and Transcendental Logic
(1929) and
Experience
and Judgment (1938), Husserl elaborated his semantic
theory and his philosophy of mathematics in its final form.
9. Apparently Husserl contributed to the field of logic more
than analytic philosophers realize. For example, some suspect that the
difference between the “formation rules” and the “transformation rules”
proposed by Rudolf Carnap, was originally proposed by Husserl, but with
different names (“laws to prevent non-sense” and “laws to prevent
counter-sense”).
174 We must remember that Carnap, in his
Der Raum includes
much of Husserl's thinking in his philosophy of space, and that between
1924 and 1925 he assisted advanced seminars given by Husserl for three
semesters.
175 We also have to remember that Husserl
influenced some Polish thinkers such as Alfred Tarski and Stanislaw
Leśniewski, the founder of mereology. Leśniewski's studies of Husserl's
Logical
Investigations (specifically the Third Investigation,
often disregarded by Husserl's scholars and analytic philosophers) made
him interested in developing a theory of parts and wholes.
A.2
- Frege's
Semantic
Theory Compared to Husserl's
We talked in Chapter 1 and 2 about Husserl's conceptions of
propositions, states-of-affairs, and situation-of-affairs. This subject
has been explored thoroughly by J. N. Mohanty, Claire Ortiz Hill, and
especially Rosado Haddock, who has written extensive articles about
this specific subject. Here I will not present anything new, just a
scheme to compare both semantic doctrines. To illustrate their
differences, I am going to use Table 10, 11 and 12.
Table 10 - Sense and
Referent of Proper Names
| Semantic
Notion |
Gottlob
Frege |
Edmund
Husserl |
| Sign |
Proper Name |
Proper Name |
| Sense |
Sense of
Proper Name |
Sense of
Proper Name |
| Referent |
Object |
Object |
As we can see, there is practically no difference between Frege and
Husserl with respect to proper names. Frege uses the example of “the
morning star” and “the evening star”.
176
Husserl uses the example of “the victor at Jenna” and “the vanquished
at Waterloo”, and of the “equilateral triangle” and the “equiangular
triangle”.
177 Each pair expresses a sense and refers to one object.
It is very important to notice that Husserl in
Logical Investigations
makes a difference between a whole set of meanings (senses) which can
refer only to one object, and those meanings which by themselves can
refer to a whole set of objects. He called
universal names to those which have only one meaning and many referents.
178
Table 11 - Sense
and Referent of Concept-Words
| Semantic
Notions |
Gottlob
Frege |
Edmund
Husserl |
| Sign |
Concept-Word |
Universal Name |
| Sense |
Sense of
Concept |
Concept |
| Referent |
Concept |
Extension of
Concept |
|
Extension of
Concept |
|
This leads us to discuss Table 11. Notice this
difference: For Frege it takes one more step from concept-words to
objects which fall under concept. He makes the concept the referent of
a concept-word. The reason for this is that he thinks about sentences,
whose structure are in subject-predicate form. The subject is a proper
name and refers to an object, the predicate is a concept word and it
refers to a concept. A concept for Frege is a function of one argument,
which can be filled by an object. So, under this scheme, the notion of
concept as referent of a concept-word works well. However, there is a
very important gap in his theory: he never explains what the sense of a
concept-word is.
In Husserl's case, he
conceives a universal name as a name having one meaning, and referring
to many objects. This can solve many problems of Frege's semantic
theory; Husserl leaves no semantic gaps like Frege does.
The subject of sentences leads us to discuss Table 12.
Table 12 - Sense and Referent of Assertive Sentences
| Semantic
Notions |
Gottlob
Frege |
Edmund
Husserl |
| Sign |
Assertive
Sentence |
Assertive
Sentence |
| Sense |
Thought |
Proposition |
| Referent |
Truth Value |
State of
Affairs |
| Referent
Base |
|
Situation of
Affairs |
|
|
Truth Value |
For Frege, the
assertive sentence has a thought as its sense, and its referent is
always a truth value. Husserl, on the other hand, says that the sense
of a sentence is a proposition and its referent is a state-of-affairs.
As we explained in Chapter 2, a state-of-affairs is the result of an
objectual categorial act with a situation-of-affairs as a referent
base. The truth value of a proposition will depend on the correlation
between propositions and states-of-affairs founded on situations of
affairs.
Here we can see the advantage of
Edmund Husserl's semantics over Frege's. Frege apparently held two very
different notions of sense.
179 One which is expressed in “On Sense and Referent” where “
a >
b” and “
b <
a”
express two different thoughts, and the one of “The Thought” in which
both of those relations express the same thought. So, “On Sense and
Referent” he can see that his notion of thought is similar to Husserl's
propositions. In “The Thought”, his notion is similar to that of
Husserl's situation-of-affairs.
It is obvious
for many that a thought should refer to a fact. However, in “The
Thought”, Frege does not conceive facts as referents, but ironically as
senses. For him, a fact is a thought that is true.
180
It is semantically acceptable that “the morning star” and “the evening
star” express senses which refer to the same object: Planet Venus. But
then it would be semantically strange to say that “the sun is in the
Milky Way” and “7 + 5 = 12” are both senses which denote the same
object.
So, with respect to semantics of sense and referent, Husserl is clearly superior to Frege.
A.3 - Frege's
and Husserl's Philosophies of Mathematics
Another frequent point of dispute is that many
believe that Frege's view of logic and mathematics is far superior to
Husserl's. If we remember Frege's original project, he was solely
interested in showing that arithmetic could be reduced to logic. We all
know the outcome of his work, the Zermelo-Russell Paradox practically
destroyed all the logical building which could derive arithmetic from
logic. Even other projects like that of A. N. Whitehead and Bertrand
Russell, who tried to show in
Principia Mathematica that all of
mathematics could be reduced to logic, failed miserably, especially
after Kurt Gödel's proof of mathematics' incompleteness.
Husserl, on the other hand, did not hold this point of view. As we have
seen in Chapter 1, he did see mathematics as logic's ontological
correlate, but the former is not reducible to the latter. He even held
that some formal-ontological categories cannot be reduced to other
formal-ontological categories. For example, he did not accept the
reducibility of arithmetic to set theory. Every effort to try to
provide a foundation of mathematics on logic has failed. It seems that
Husserl was right after all.
An interesting
point of comparison of both of their doctrines has to do with
non-euclidean geometry and other mathematical notions. Frege, did not
accept non-euclidean geometry as a legitimate mathematical enterprise.
Husserl was more careful than that. His idea of a mathesis universalis
as theory of manifolds did allow the mathematical truths of
non-euclidean geometries as well as the scientificity of what he called
then “imaginary numbers” (negative roots, fractions, irrational
numbers, decimals, among many others).
181
Another point of advantage of Husserl's views with respect to Frege's
is that his philosophy of mathematics and mathematical epistemology are
able to overcome the paradoxes of naïve set theory. Frege's logicism
collapsed because of the Zermelo-Russell Paradox. However, in
Experience and Judgment, Husserl uses sets as examples of objectual
categorial acts, and, as we have seen in Chapter 2, in principle a new
set can always be constituted on top of other ones. Rosado (in Hill
& Rosado, 2000) has pointed out the way this hierarchy of
objectualities practically blocks the paradoxes of naïve set theory.
For example, the fact that in principle every set can be constituted on
another set and that there is a hierarchy blocks the possibility of a
set of all sets. This prevents the Cantor Paradox from happening. The
hierarchical aspect of objectual acts also blocks the Zermelo-Russell
Paradox, since we cannot form sets which are elements of themselves.
182
And last, but not least, Husserl's view of mathematics has provided
perhaps the only platonist epistemology that can be explained
naturally. Unfortunately, Frege could not provide such an epistemology,
he was content only with grasping thoughts and senses, but nothing more
than that.
Frege made many contributions to
the fields of logic and mathematics, but the truth is that Husserl not
only contributed to them, but also his view of them is extremely close
to the way they are developed in the twenty-first centuries.
Footnotes:157For
a more thorough study on this subject, and a full demystification of
wrong conceptions about Husserl see: Hill, 1991; Hill & Rosado,
2000; Bernet, Kern & Marbach, 1999, pp. 13-57; Mohanty, 1974,
1982b; Hintikka, 1995, pp. 78-105; and Rosado, 2008b. [
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158Coffa, 1998, pp. 68-69; Frege, 1894/1972, pp. 323-330; Hill, 1991, pp. 14-16, 58-62, 66-70, 71-86. [
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159Hill & Rosado, 2000, pp. 96-97. [
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160Hill & Rosado, 2000, p. 98. [
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161Mohanty, 1974, pp. 22-23. [
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162Hill, 1991, pp. 16-17. [
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163Notice that it is only
three
pages, not eight as the typographical mistake of the old English
edition seems to imply. This typographical mistake, unfortunately has
fueled the myth about Husserl being dramatically changed by Frege. In
reality, Husserl leaves most of his criticism to Frege intact
after his turn from psychologism (see LI. Vol I. §46; see also Hill & Rosado, 2000, pp. 4-5). [
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164LI. Vol. II. Inv. I. §15. [
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165Tieszen (1995) seems to fall in this kind of error. See also Rosado, 1997, pp. 387-395. [
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166Moran
(2000) makes an excellent summary of Husserl's phenomenological
doctrine, but his exposition has many flaws, among them the confusion
between categorial intuition and eidetic intuition (see pp. 119-120),
and he also confuses the concepts of state-of-affairs and
situation-of-affairs (p. 112). In
Logical Investigations
eidetic intuition appears as just one among other kinds of categorial
intuitions.(LI. Vol. II. Inv. VI. §52) However, in his later works,
there is a qualitative difference between both intuitions (I. §§3-4).
[
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167Hill & Rosado, 2000, p. xi; Verlade, 2000, p. 3. [
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168Hill, 1991, p. 17. [
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169Hill & Rosado, 2000, p. 3. [
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170Hill & Rosado, 2000, p. xi. [
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171Rosado, 2008b, p. 31. [
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172Hill & Rosado, 2000, p. xi. [
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173Hill, 1991, pp. 2-3. [
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174Hill & Rosado, 2000, p. 203. [
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175Friedman, 1999, pp. 46-48; Hill & Rosado, 2000, pp. 202-203. [
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176SR. p. 32. [
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177LI.
Vol. II. Inv. I. §12. It is very interesting that in a letter to P.
Linke, Frege borrowed Husserl's example and changes it a bit so he can
explain his notion of the sense of proper names: “the loser of
Waterloo” and “the victor of Austerlitz” (Hill, 1991, pp. 93-94). [
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178LI. Vol. II. Inv. I. §12. [
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179See Rosado's article “On Frege's Two Notions of Sense” in Hill & Rosado, 2000, pp. 53-66. [
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180T. p. 74. [
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181Hill & Rosado, 2000, pp. 161-178. [
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182pp. 235-236. [
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