Essential Forms for Natural Science
"Everything depends upon the interconnections that present intelligible unity" (55)
Husserl explains in The Idea of Phenomenology that to know is to perceive the absolute givenness of a phenomenon; to "see that the object [of knowledge] constitutes itself in knowing."(xx) The point of his lecture series is to propose a method for accessing "pure seeing" as the first, immediate, step in acquiring knowledge with what he calls the "phenomenological reduction." He thinks that if this reduction of the buzzing, werring, confusion of conscious experience is successful, one can be enabled to understand (that is, categorize, divide up, tokenize, or "chunk" and relate the categories interconnectedly to the rest of knowledge (all other categories)) what is really occurring in the cogitatio.
What Husserl is saying in his book is not any concept in particular like "apple" or "red" or "chess" is an object of thought. What he is describing is the connections between those concepts (it is a method of organizing the concepts and connecting them together). The phenomenological reduction what lies between the words of a sentence (it is the glue of understanding which holds the concepts in meaningful conscious contemplation).
I think the best way of explaining what Husserl talks about is to analyze some of the key terms that he uses and to present them in a natural order of dependence such that the more complex terms are explained by the explanation of the less complex terms. I will move from "consciousness" and "phenomenon" to the explanation of Husserl's sense of "givenness" and his "phenomenological reduction." I will show that this is a method for grounding the "natural attitude" (of which Husserl is interested beyond the scope of his lectures) by supporting his exercise of bracketing reality (epoche). The science of phenomenology isn't necessary or real per se, but it is a useful tool for understanding one's situadedness.
Consciousness (the perceiver of all things)
Consciousness is the existential thing that is perceiving (the perceiver). It is the thing that is knowing. It is Descartes' "I." All things being equal, I am this thinking thing that is considering my situadedness (that is, my being in this reality). Consciousness is that which looks out into reality and has the experience (whatever that may be).
Phenomenon (thought-object)
A phenomenon is that which is being perceived by consciousness (it is the object of thought). Thinking is about something, and that thing is called a phenomenon. Consciousness itself is a phenomenon when I parse it as an object in language. When I refer to that which is perceiving, I am referring to a thing. It just so happens that that thing is such a thing that is able to perceive other things.
I'm not thinking here that "things" are necessarily "objects" (as objects in some physical world). At this point, I mean simply "objects of thought" which could be physical or not. What is important is the thing's aboutness. It is the conscious intention that about which some thing is what is known(or thought or considered). All such about-things are referred to as phenomena.
Cogitatio (phenomenal awareness)
The cogitatio is the "being" of consciousness, or the act of experiencing phenomena, or the form of knowing which lies between consciousness and its objects. That is, where there is consciousness and its intentional object (some phenomenon) the human link between the two is what Husserl calls the cogitatio.(xx)
Appearance (ness-ness)
If the cogitatio is the form of knowing between consciousness and phenomena, then appearance is the quality of that form (the "what it's like" of a phenomenon). It is that which shows itself or makes itself immediately manifest to the consciousness as a phenomenon.
"[Appearances] are not themselves the objects, and do not really contain the objects, ...[but] in a certain sense create objects for the ego" (52). So, it's not that an appearance is the object itself, but it is the phenomenon that is held in the consciousness. It is the object-as-in-the-mind. Husserl's point is that this is all that can be known absolutely (these appearances) for they are the only things that we are able to be conscious of.
Givenness (immediate perception qua perception)
Givenness is the immanent perception that is given to consciousness. I don't have to think about it, it is just there (e.g., the redness of red is simply there in my mind before any other thought I could have about red can be formed). This is a very broad concept, and it encompasses a large gamut of experience. For example, givenness is also present in illusion and hallucination and even in dreams or the imagination. There is no distinction here about what is actually real, only between what is actually present, or immanent, or manifest in consciousness.
Think of a spoon placed in a glass of water, the handle sticking out into the air and the bottom immersed in liquid. Because of the refraction of light through two different mediums (air and water) the spoon appears to be bent at the surface of the water. In the natural sense, the spoon is not really bent (because of light refraction), but in the phenomenological sense (as a purely given sense of immediate perception of appearances) the spoon is indeed bent. That's just what is given to our visual seeing of the spoon-as-immersed-in-a-glass-of-water. That phenomenon is what is given, before any of the rest of our analyses and rationalizations about the nature of material reality come into play to reorganize our pure seeing into "understood seeing" as a non-bent-spoon-which-appears-bent really still straight, the water causing an illusion of bentness.
What you see is what you get. That is given.
Objectivity (given appearance as object)
The phenomenality of the phenomenon (the division of the all flowing, temporal somethingness (i.e., given reality) into categories of thought (i.e., concentrated, artificial (and arbitrary) divisions of the aspects of somethingness into tokens) which can be contemplated by human consciousness) is what Husserl refers to as "objectivity."(xx)
The problem which objectivity solves is the inability to describe reality in human thought as such. All of reality cannot be held in mind at one time (i.e., finite beings cannot consider the infinity of universal reality). It must thus be chopped up into pieces small enough to hold in thought in order that those pieces may then be psychologically manipulated or understood.
The idea here, is that Husserl is interested in objects as they are for consciousness (givenness) instead of objects as they are in the world (transcendence). The thought-object (the intentional act of thought, or the object as thought) is what is absolutely real. It is what the transcendent objects mean (i.e., they are phenomena that appear to consciousness as such). It is this sense of the reality of objects that is objectivity.
Essence (the unfolding of being)
Essence is what is given (e.g., red's redness). If givenness is the direct perception of an appearance of objectivity, then essence is that which is given.
It's all about meaning. I can hold in my mind the idea of warm-light-of-a-certain-quality. But instead of thinking in images of pure redness and ranges of arbitrarily divided chunks of reality, I call this idea "red" and can talk about it using this reference with other people. They know what I mean by the universal definition of "red" that has been agreed upon as a convention for referring to a certain warm range of the light-spectrum. Without it I could not communicate in an efficient manner, always having to fully define my thoughts in terms of experience (e.g., "what I mean is the visual phenomenon that is present in fires and fire trucks and blood, etc."). It is much more efficient to simply say "red" when that is what is meant than to attempt to relate all of one's personal life experience to that of another's. We could spend the rest of existence simply trying to communicate just what visual phenomenon it is that we mean in the idea of redness we have in our minds.
What I'm trying to say in a convoluted way is that in the presence of experience (whole reality given at once), we make distinctions inside that experience of particular properties and qualities that we can section off from other properties and qualities to be able to think and speak more concisely. It's arbitrary what we call "red," but the redness (a particularly sectioned off property and quality of experience) is not. Experience is essential and therefore its specific, sectioned-off properties and qualities are essential as well. Given some property of experience, dividing it and isolating it for thought, naming it "red," and considering what makes it red, we can see that it is the redness of red which is its essential feature. Essence is what is given to us in experience.
Evidence (an interconnected belief of the essences of the perception of reality)
Evidence is the validity of an essence verified against all the rest of consciously experienced essences. It is the interconnectedness of what is given between all else that has been given. It is the relation of what is immanent to what is cognized (what is knowing to what is known).
Evidence is the placement of the sectioned-off essence into the great puzzle of experience-as-a-whole. We can't consider all of experience at once (because we are finite), but we can consider an essence's neighbouring qualities to see if they fit together with the quality of essence under consideration. For example, my experiencing the appearance of red relates itself to my knowledge of the light spectrum, that it is a certain domain of the entire range of possible light, that it is a colour, that it is such a colour that is "warm," that it is the colour of valentines and blood, that it is not blue, etc. Placing red into the section of the light-spectrum which is redness is using the non-red parts of the light spectrum for evidence. That red "fits" into that particular, warm side of the spectrum is evidence that the essence of the phenomenon of red is real (that is, evidence is the fitting-into of an essence into the combination of essences which make up the essence of "reality").
Universals (common evidence of the essences of the world)
Universal evidence is the related, common essence between disparate minds. If essence is the personal understanding of a definitive aspect of reality and evidence is its placement amongst the other experienced essences, then universal evidence is an expanded, public understanding that can be agreed upon as such an essence between other consciousnesses.
I don't mean that it is "agreed upon" in the way that two people agree with one another to play a game of chess, but that they agree that the game they are playing is such a thing that has certain rules and structures that all people in general agree is what is called "chess." That is, in the universal mind, the life experience of moving sculpted pieces of matter across a checkered surface following a particular set of rules is unified in a way that it is called "chess." Chess is placed amongst the essences of reality and validated as being so placed in general.
This is problem which language solves, but representing conventional tokenizations of reality and placing linguistic references upon those tokens (e.g., redness is called "red," and checkered-sculpture-game is called "chess"). If we did not perform this act of abstraction (taking particular, individually tokenized experience and standardizing its reference to universals) we would each of us be isolated in our own unique life experiences cut off from shared-evident thought (i.e., life as my life cannot be described but only in a more general form to some other life).
The Natural Attitude (that the world exists as real)
The "natural attitude" is the stance that the world is real (i.e., not a fiction in the sense of a hallucination or idea). It is a solid, universal space of shared perceptions.
It's just one possible sense of human existence for the sake of placement (otherwise, without any other sort of metaphysical stance, what would human being be other than a buzzing, werring confusion?) Other such stances could be idealism or sollipsism, but it is the "natural attitude" which interests Husserl because of its usefulness in describing the situation which provides us with a language for describing phenomena in a fuller, more accurate (in the sense of more descriptive), practical manner (i.e., it provides us with the tools needed to have a discourse).
Epoche (make no assumptions)
Husserl abstains from the consideration of the existence of reality in order to understand a more fundamental level of how it is that we can know what we know. That is, he is concerned about not what we know, but that we know. In order to start such an investigation, Husserl believes that we must look to the side of whatness and consider thatness (a diverting of attention to focus on what is immanent).
Heis not denying reality's existence, but neither is he affirming it. He simply wants to hold the "natural attitude" in abeyance whilst he analyzes its possibilities and validities (e.g., given appearances of objectivity through phenomenological reduction). Reality is what is dubitable and Husserl wants to hold it to the side and make no use of it in the science of phenomenology.
Phenomenology (the analysis of what is given)
Husserl names a new science that is separate from the natural sciences in that it is the analysis of the immanent moment of conscious experience (put a different way, it is the study of the cogitatio and how it is that which it is).
Phenomenology is not concerned with what is actually the case beyond consciousness (transcendental judgments are entirely beside the point, 30). "Nothing is ... assumed concerning the existence or non-existence of reality" (34). These sorts of assessments of situatedness are left for other forms of study like natural science which maintains and elaborates upon the "natural attitude." What concerns phenomenology is the form of our knowing. In this case, that we perceive appearances as such and that we are limited to judging reality based upon these sorts of immediate givens. The appearances are real and exist to be considered. Whether or not those appearances correspond to an outside object of material, or are merely an idealism of mentation, is a question for different scientific investigations.
Phenomenological Reduction (givenness, not transcendence)
The purpose of Husserl's series of lectures in The Idea of Phenomenology is to explain the validity of his a method for considering experience which can be used as a grounding for other sciences and natural beliefs. He calls this method the "phenomenological reduction."
The reduction is that our "natural attitude" of the world (that it exists as really possible) is put aside, and what we are left with is pure givenness. We cannot deny that consciousness exists, that it perceives appearances, that these appearances (as given) are essential to thought, and that they are evident in their placement to all other perceivable essences (i.e., interconnected, intelligible unity). I can doubt that the apple in front of me is real (perhaps it is a hallucination). My natural attitude that there is an apple in front of me prevents me from being able to consider its validity. But when I use the method of phenomenological reduction to understand the apple as, simply, an appearance in my consciousness (as real on a phenomenological level) I can use this givenness to relate an essence of appleness to others. I am afforded the language (the tools) needed to understand its reality. The point is that the apple cannot simply be assumed, but built up as existent based on what is indubitable (that is, givenness).
This "building up" is what is made possible by the method of phenomenological reduction. It is Husserl's method which breaks conscious experience out of solipsism and combines with a sense of transcendence a real, physical world that can be understood as manifest. Taken outside the individual, the interconnections between minds and their shared unity of givenness form the empirical evidence of natural science.
References
Husserl, Edmund. The Idea of Phenomenology. Kuwer Academic Publishers, 1999.