Perhaps the unifying thread among his diverse activities was a type of phenomenology tinged with his strong dislike of metaphysics. Therein lies both a strength and a weakness within Machian thought: a methodological strength from the perspective of phenomenology, and a weakness arising from an internal tension between Mach’s anti-metaphysical sentiment and the rigorous methodological demands of phenomenology. Such a tension would arise from the notion that phenomenology is tabling of questions about metaphysical realities - not a denial of such realities - and an exclusive attention to the metrics and patterns of appearance.
To be sure, Mach or a Machian would respond by pointing out that, as David Woodruff Smith has indicated, there is a variety of types of phenomenology, some of which might allow assertions or speculations about the reality or irreality of the Ding an sich. Mach wants to use the methodology of phenomenology while at the same time making a dogmatic statement about the nonexistence of certain metaphysical constructs. The mainstream of phenomenology, typified by Edmund Husserl, strictly demands that one refrain from assertions about metaphysical entities. While there is room for Mach to consider himself a phenomenologist, he certainly would be outside the mainstream of phenomenology.
We might compare three approaches: Husserl won’t - chooses not to - occupy himself with questions about the nounema behind the phenomena: this is a conscious methodological choice to refrain from discussion of the noumena. The Vienna Circle and the logical positivists assert that language about the noumena is nonsense, i.e., that it is not possible to discuss it. Mach seems to start from something like a logical positivist approach, but occasionally slips into making assertions that the noumena does not exist. Such assertions would both violate Husserl’s policy of voluntarily restraining one’s self, as a methodological principle, from making statements about the noumena, and violate the Vienna Circle’s notion that such assertions are meaningless.
Some of Mach’s remarks, taken in isolation, fall within traditional phenomenology. (Mach’s spelling sometimes appear idiosyncratic to eyes accustomed to twenty-first century German, but a variety of spelling reforms were being discussed and circulated in his day; those proposals have left their fingerprints on his texts.) To say that metaphysics is an idle pursuit, that it should be eliminated from the natural sciences, or that such questions can be meaningfully pursued in discussion and debate, are statements with which, with perhaps a little fine-tuning, Husserl’s disciples could agree.
Meinen erkenntnisskritisch-physikalischen und den vorliegenden sinnesphysiologischen Versuchen liegen dieselbe Ansicht zu Grunde, dass alles Metaphysische als müssig und die Ökonomie der Wissenschaft störend zu eliminieren sei. Wenn ich nun hier auf die abweichende Ansichten nicht ausführlich kritisch und polemisch eingehe, so geschieht dies wahrlich nicht aus Missactung derselben, sondern in der Überzeugung, dass derartige Fragen nicht durch Discussionen und dialectische Gefechte ausgetragen werden.
As a physicist, Mach applied the phenomenological method to the concept of bodies enduring over time. This version of the problem of identity is not new, but Mach develops the argument in a novel direction. He links our tendency - in his view, our mistaken tendency - to see a stronger identity over time than evidence warrants as the expression of a fear. It is our fear of death, and more generally our fear of a loss of identity’s duration over time, which predisposes us to embrace a metaphysical notion of identity, i.e., a notion which, in Mach’s view, goes beyond empirical sense data. Mach links our inclination to posit the identity of an object over time to our inclination to posit the duration of our own “self” or “ego” over time; he seems to indicate that the one inclination arise from the other, and that our desire to perceive our own existence’s duration arises from a fear of death.
Das Ich ist so wenig absolut beständig als die Körper. Was wir am Tode so fürchten, die Vernichtung der Beständigkeit, das tritt im Leben schon in reichlichem Masse ein.
Mach’s strong drive to deny any metaphysic leads him in psychology to deny any “ego” or “self,” fearing that any such psychological construct would ultimately open the door to dualism or metaphysics. In physics, that same drive leads him to construct a descriptive model of natural science, or observational science, along the lines of phenomenology. Science, for Mach, is the collecting and measuring of experience. Science describes sense data in the most simple and objective manner - which usually means quantitatively - and describes patterns which exist among those data, using the tools of geometry and algebra. While starting with a program which seeks to exercise admirable restraint - along the lines of Husserl’s phenomenology or a sober Kantianism - Mach seems to get carried away, and rather than simply refraining from passing judgment on metaphysical assertions, wants rather to deny them. His heirs, the logical positivists and the Vienna Circle, will attempt this restraint as they declare metaphysical propositions to be, not false, but meaningless. Mach seems at times to fall short of that development, and rather is eager to deny the existence of Ding an sich. Allan Janik and Stephen Toulmin write:
Mach’s reduction of all knowledge to sensation forms the base on which all of his thinking is founded. The task of all scientific endeavor is to describe sense data in the simplest or most economical manner. Mach actually prefers to designate sense data by the more neutral and noncommittal term “elements”; it is the feature of simplicity or economy which is distinctively scientific. So Mach’s point of view is that of a thoroughgoing phenomenalist; the world is the sum total of what appears to the senses. So, dreams constitute “elements” in the world just as much as any other class of elements, for “inner” experience is experience quite as much as “outer” experience is. Abstract conceptions, ideas, representations, are similarly reduced to sense data, by being identified as species concepts which enable us to deal with groups of “elements” efficiently.
Reflecting philosophy’s insights into, and concerns with, language, Mach notes that our use of names, and the thoughts to which they refer or for which they are symbols, reveal our tendency - both as a desire and as simply a habit of thought - to posit the continued existence of objects over time. He notes that our inclination towards such concepts is strong enough that “Ship of Theseus”-type objections from Aristotle or Heraclitus make little impact on it.
Die zweckmässige Gewohnheit, das Beständige mit einem Namen to bezeichnen und ohne jedesmalige Analyse der Bestandteile in einen Gedanken zusammenzufassen, kann mit dem Bestreben die Bestandteile zu sondern in einen eigentümlichen Widerstreit geraten. Das dunkle Bild des Beständigen, welches sich nicht merklich ändert, wenn ein oder der andere Bestandteil ausfällt, scheint etwas für sich zu sein.
In a classic phenomenological formulation, Mach tells us that objects simply are a collection of sense data. The classic formulation, however, leaves him with a classic problem. If we think of each sense datum as a point - maybe structured with three places: time, location, and which of the five senses obtained the input - then we think of an object as a set of such points. With Mach’s denial of any enduring identity of an object beyond the positing of such a set, it seems that he might be forced to acknowledge as an ‘object’ some very counterintuitive juxtapositions of sense-data, e.g., non-contiguous sets.
By his own restrictions, Mach may not say that an object is the collection of my “sense-data of it,” because the phrase “of it” imports the very metaphysical notion which he opposes. He must rather say that an object is a collection of sense-data. He may be forced to acknowledge some unlikely objects consisting of arbitrary collections of sense-data. I might take my sense-data of listening to a piano in Michigan in 1983 and place it into a set with my sense-data of flying in an airplane over Nebraska in 1975, yielding a set with more than one sense-datum in it, and thereby an “object” according to one understanding of Machian phenomenology.
Das Ding, der Körper, die Materie ist nichts außer dem Zusammenhang der Elemente, der Farben, Töne u.s.w. außer den sogenannten Merkmalen. Das vielgestaltige vermeintliche philosophische Problem von dem einen Ding mit seinen vielen Merkmalen entsteht durch das Verkennen des Umstandes, dass übersichtliches Zusammenfassen und sorgfältiges Trennen, obwohl beide temporär berechtigt und zu verschieden Zwecken erspriesslich, nicht auf einmal geübt werden können. Der Körper ist einer und unveränderlich, so lange wir nicht nötig haben, auf Einzelheiten zu achten.
Thus Mach responds by saying that an object’s - a body’s - unity and continuity are illusions and dissolve under disciplined analysis of our observations of it. Allan Janik and Stephen Toulmin write:
As a positivist, Mach was absolutely opposed to any sort of metaphysical speculation. He equated metaphysics with mysticism and consequently with obfuscation in science. In psychology he was a relentless opponent of all those who posited the “ego” as an entity; he rejected any position which smacked of the slightest hint of dualism, for he said that all dualism culminates in metaphysics. Indeed, as an ardent positivist, he did not recognize philosophy to have any legitimacy apart from science, and he continually insisted that he was not a philosopher. David Hume, the destroyer of all metaphysical claims to truth, and Georg Christoph Lichtenberg, the enemy of a pseudo science, were his philosophical heroes. Mach was, in fact, the first man to draw attention to the philosophical significance of Lichtenberg, whose writings soon became popular and influential in the artistic and intellectual circles of Vienna.
Using a classic example of the optical illusion of a straight stick or pencil partially submerged in water, and of its apparent bentness due to refraction despite our “knowledge” that it is straight, Mach wishes to reformulate our conclusion about the pencil. He rejects the usually conclusion that the pencil is straight but appears bent. He rejects that formulation because it smacks of metaphysics inasmuch as it contrasts being to appearance, and he fears that this is the toehold of metaphysics. He rather wants to formulate the conclusion thusly: the pencil is optically bent but haptically straight. (If we close our eyes and put our hands into the water, there is no evidence or sense of bentness.) By rephrasing this classic example according to his phenomenological program, he hopes to deny entry to metaphysics.
Man pflegt in der populären Denk- und Redeweise der Wirklichkeit den Schein gegenüber zu stellen. Einen Bleistift, den wir in der Luft vor uns halten, sehen wir gerade; tauchen wir denselben schief ins Wasser, so sehen wir ihn geknickt. Man sagt nun in letzterem Falle: Der Bleistift scheint geknickt, ist aber in Wirklichkeit gerade. Was berechtigt uns aber eine Tatsache der andern gegenüber für Wirklichkeit zu erklären und die andere zum Schein herabzudrücken? In beiden Fällen liegen doch Tatsachen vor, welche eben verschieden bedingte, verschiedenartige Zusammenhänge der Elemente darstellen. Der eingetauchte Bleistift ist eben wegen seiner Umgebung optisch geknickt, haptisch und metrisch aber gerade.
In physics, Mach’s phenomenology led him to oppose Newton’s view of space as substantival. Newton had argued that there is a thing, an object, called ‘space’ - that when we use the word ‘space,’ we are in fact referring to a physical reality. Historically, Leibniz opposed Newton and argued that space does not have the status of a Ding an sich, but exists merely as the description of the relative locations of physical objects. Newton would have argued that if one removed all matter and energy from the universe, one would still have empty space. Leibniz would have argued that the removal of all matter and energy would leave nothing. For Newton, empty space and nothing are two different situations; for Leibniz, they are the same. Mach winds up being closer to Leibniz than to Newton. Mach accuses Newton of dabbling in metaphysics when the latter posits space as real. Lawrence Sklar writes:
Ernst Mach was simultaneously a working theoretical physicist and a positivist philosopher. He made, in his Science of Mechanics, a heroic attempt to replace Newton’s theory by an alternative theory. The alternative is supposed to be adequate to account for the inertial forces Newton took as the primary data supporting his doctrine of substantival space, but to lack any such “metaphysical” elements that infected, according to Mach, the Newtonian scheme.
Mach seems to indicate that while physicists are well aware of the tendency of prejudices to sneak into their work, and are therefore alert to look out for them, psychologists are by contrast not as aware of the subtle influences which preconceived notions can have in their work. Here, Mach is perhaps thinking of the notion of an object or a body from physics working its way into psychology as the notion of the ‘ego’ or ‘self’ or ‘mind.’ Part of Mach’s program, then, is to purify psychology and structure it so that it will keep such prejudices at bay. A psychology structured according to Machian phenomenology will smell the metaphysics which clings to the concept of the ‘self’ and reject that concept.
Der Physiker hat oft Gelegenheit zu sehen, wie sehr die Erkenntnis eines Gebietes dadurch gehemmt werden kann, dass anstatt der vorurteilslosen Untersuchung desselben an sich, die auf einem andern Gebiet gefassten Ansichten auf dasselbe übertragen werden. Weit bedeutender ist die Störung, welche durch solche Übertragung vorgefasster Meinungen aus dem Gebiet der Physik in jenes der Psychologie entsteht.
Accordingly, Mach rejects the notion that psychological terms like ‘will’ refer to anything beyond a set of sense-data. One might detect traces of Mach’s encounter with Schopenhauer’s books here. In any case, Mach is quite clear that the word ‘will’ does not refer to a psychological object - indeed, Mach would reject the very notion of a psychological object beyond a collection of experiences - and sees rather the ‘will’ as something physical, organic, and biological:
Ich verstehe unter dem Willen kein besonderes psychisches oder metaphysisches Agens, und nehme keine eigene psychische Kausalität an. Ich bin vielmehr mit der überwiegenden Zahl der Physiologen und modernen Psychologen überzeugt, dass die Willenserscheinungen aus den organisch-physischen Kräften allein, wie wir kurz aber allgemein verständlich sagen wollen, begreiflich sein müssen.
Mach is, then, a phenomenologist of some type. The question is: of which type? To which extent would Mach harmonize with Husserl? Having established himself as a phenomenologist, Mach wishes to apply his phenomenology to empirical and observational science - he would hardly allow the existence of any other type of science. Mach wishes to restructure physics and psychology according to his phenomenology, and in so doing, is in conflict with Newton. To which extent was Mach successful? On the one hand, he had a significant influence on Einstein; on the other hand, Newton remains a powerful influence.
