“For as many of you has have been baptized into Christ have put on Christ. There is no longer Jew or Greek, there is no longer slave or free, there is no longer male of female, for you are all one [εις: unum] in Christ Jesus. And if you are Christ’s, then you are Abraham’s offspring, heirs according to the promise” (Gal. 3, 27-29).
Ratzinger comment: “It is important to take notice of the fact that Paul does not say, for example, `you are one thing,’ but rather stresses that `you are one man.’ You have become a new, singular subject together with Christ and, in consequence – through the amalgamation of subjects – find yourselves within the purview of the promise.” (Josef Ratzinger, “The Spiritual Basis and Ecclesial Identity of Theology,” The Nature and Mission of Theology, Ignatius  52).
Significant Change of Epistemological Perspective: (i.e., object of subject)
This appears to be a contradiction. We ask, “How can the many be one, and the one many? How do we resolve this?” The radical answer consists in re-evaluating what we take for granted, i.e., that we are observers of reality in a such a way that we stand outside of it. The great shift that must take place is to do what the theology of faith of the middle ages and modern physics have done: enter into the reality to be known by experiencing ourselves as part of it. This is the mother of all paradigm shifts that would put an end to the intellectual dead end in which modern philosophy from Descartes to the present day deposited us.
Besides his understanding of the meaning of faith in St. Bonaventure - where “the receiving subject is always also a part of the concept of revelation,’” the subject as image of God being the very revelation of God when “he” is activated as self gift - Josef Ratzinger has found a comforting confirmation of this epistemological stance in modern physics where the scientist does not stand outside the experiment as observer but enters into it as interactive with it. Hence, relativity and quantum mechanics arise within an epistemology cognizant that the observer experiences-self-experiencing-thing, and hence, having only a particular perspective.
Ratzinger comments that “The physicist is becoming increasingly aware today that we cannot embrace given realities – the structure of light, for example, or matter as a whole – in one form of experiment and so in one form of statement; that on the contrary from different sides we glimpse different aspects, which cannot be traced back to each other. We have to take the two together – way the structure of corpuscle and wave – without being able to find any all-embracing aspect – as a provisional assessment of the whole, which is not accessible to us as a unified whole because of the limitations implicit in our point of view.”
The result of this experience of the self (subject) experiencing the sensible thing (object) from a finite and determined position within physical reality has suggested the “law of complementarity” in physics introduced by Niels Bohr. According to this, Ratzinger suggests that “The intellectual approach of modern physics may offer us more help here than the Aristotelian philosophy was able to give. Physicists know today that one can only talk about the structure of matter in approximations starting from various different angles. They know that the position of the beholder at any one time affects the result of his questioning of nature.” The very nature of the questions that we ask depends on the experience of our own placement in the whole. Hence, Ratzinger asks “Why should we not be able to understand afresh, on this basis, that in the question of God we must not look, in the Aristotelian fashion, for an ultimate concept encompassing the whole, but must be prepared to find a multitude of aspects which depend on the position of the observer and which we can no longer survey as a whole but only accept alongside each other, without being able to make any statement about the ultimate truth…”
The whole issue of “oneness” as opposed to being “united” is the issue of being an individual substance. Individual substances are “united” because they are considered to be “in-themselves” and not “in-another.” The connections between them are necessarily “accidental.” This notion of the individual as substance in itself is directly connected with first level experience through the senses and the resulting abstractive concept that is an intellectual cipher that points to reality as cipher. It is a result of standing “outside” of what is “observed” and naming it symbolically. The danger is that we impose on reality our way of knowing it. We see things the way we are, not the way real being is.
As there has been a development of the awareness of the existential reality of the subject in the last century, concomitant with the progressive collapse of rationalism and its spawn, ideology and the progressive collapse into relativism and nihilism, there is a revived sense of experience both of the sensible world and of the acting self. In this regard, Ratzinger mentions that "E. Schrödinger has defined the structure of matter as `parcels of waves’ and thereby fallen upon the idea of a being that has no substance but is purely actual, whose apparent `substantiality’ really results only from the pattern of movement of superimposed waves. In the realm of matter such a suggestion may well be physically, and in any case philosophically, highly contestable. But it remains an exciting simile for the actualitas divine, for the absolute `being-act’ of God, and for the idea that the densest being – God – can subsist only in a multitude of relations, which are not substances but simply `waves,’ and therein form a perfect unity and also the fullness of being.” He then emphasis the epistemological strategy that “the observer himself enters into the experiment and only by doing so can arrive at a physical experience. This means that there is no such thing as pure objectivity even in physics, that even here the result of the experiment, nature’s answer depends on the question put to it. In the answer there is always a bit of the question and a bit of the questioner himself; it reflects not only nature-in-itself, in its pure objectivity, but also gives back something of man, of our individuality, a bit of the human subject.”
It is most suggestive to take thinkers like Bishop Berkeley and David Hume seriously in their understanding of sensible perception. For Berkeley, the esse est percipi seems to lead to the absurdity that he is the only one who exists. That the only reality is the self perceiving a supposed world, but that world may or may not exist in reality since perception is a subjective experience. We see colored shapes; we hear sounds; we touch surfaces although "on the other side" of the perception there may be only variations in quantity of waves and spaced particles. Is there any sound of a tree falling in a forest if there is no hearing to perceive it? Owen Barfield suggests: “Look at a rainbow. While it lasts, it is, or appears to be, a great arc of many colours occupying a position out there in space. It touches the horizon between the chimney and that tree; a line drawn from the sun behind you and passing through your head would pierce the center of the circle of which it is part. And now, before it fades, recollect all you have ever been told about the rainbow and its causes, and ask yourself the question Is it really there?”
Barfield goes on: “Now look at a tree. It is very different from a rainbow. If you approach it, it will still be `there.’ Moreover, in this case, you can do more than look at it. You can hear the noise its leaves make in the wind. You can perhaps smell it. You can certainly touch it. Your senses combine to assure you that it is composed of what is called solid matter. Accord to the tree the same treatment that you accorded to the rainbow. Recollect all you have been told about matter and its ultimate structure and ask yourself if the tree is `really there.’ I am far from affirming dogmatically that the atoms, electrons, nuclei, etc., of which wood, and all matter, is said to be composed, are particular and identifiable objects like drops of rain. But if the `particles’ are there, and are all that is there, the, since the `particles’ are no more like the thing I call a tree than the raindrops are like the thing I call a rainbow, it follows, I think, that – just as a rainbow is the outcome of the raindrops and my vision – so, a tree is the outcome of the particles and my vision and my other sense-perceptions. Whatever the particles themselves may be thought to be, the tree, as such, is a representation.”
Barfield then takes it a step further: “A representation is something I perceive to be there…. He now deals with perception: Perception takes place by means of sense-organs, though the ingredient in it of sensation, experienced as such, varies greatly as between the different senses. In touch I suppose we come nearest to sensation without perception; in sight to perception without sensation. But the two most important things to remember about perception are these: first, that we must not confuse the percept with its cause. I do not touch a moving system of waves or of atoms and electrons with relatively vast empty spaces between them; the name of what I touch is matter. Second, I do not perceive any thing with my sense-organ alone, but with a great part of my whole human being. Thus, I may say, loosely, that I `hear’ – all that I ever hear simply by virtue of having ears – is sound. When I `hear a thrush singing,’ I am hearing, not with my ears alone, but with all sorts of other things like mental habits, memory, imagination, feeling and (to the extent at least that the act of attention involves it) will.”
Barfield concludes his point: “On almost any received theory of perception the familiar world – that is, the world which is apprehended, not through instruments and inference, but simply – is for the most part dependent upon the percipient.”
The short explanation is the following: The only subsisting existent that I experience directly – i.e., without the distortion of mediation - is myself, I, in the moment of freee action, or self-determination. Everything else I experience through the mediation of perception such as sensation or conceptualization. And it is important to insist that it is the experience of I as being, and not consciousness. Wojtyla says, “In determining myself – and this takes place through an act of will – I become aware and also testify to others that I possess myself and govern myself. In this way, my acts give me a unique insight into myself as a person. By virtue of self-determination, I experience in the relatively most immediate way that I am a person.”
As there is no perception of the rainbow without a perceiver, so also with the whole of sensible reality. We do not experience the reality of what is perceived in the senses. What we perceive is the perception. The reality that we experience is the I experiencing itself - as being - perceiving through the senses. We do not perceive the reality of the perceived, but the reality of ourselves perceiving. The being I experience when I sense something is I myself, the reality, from whom I transpose to the thing now sensed.
And this is the moment of the experience of "values." Good and evil are not abstract metaphysical deductions (although they can be as in the Summa of St. Thomas) but direct experiences of the self in the free act of self-determination. They are absolutes because they are direct experiences of being, the being of the self that is self-experiencing in the free act. This being of the self has been made in the image and likeness of God who alone is good "There is only one who is good" (Mt. 19, 17). Since God alone is total self-gift, in the tendency of the self as image, one experiences the consciousness of good and evil that we call "conscience." Revelation speaks to that tendency and calls it to act. Agape speaks to eros.
Newman explains this (in the Grammar of Assent) with regard to the experience of causality. I do not experience causality outside of my self in my sensible perceptions. When I see a red ball in motion hitting a green ball, and the green ball moves, I associate the motion of the green ball with the red ball. I do not experience causality through sensation. I associate. However, when I decide to move myself from here to there, I experience myself moving myself as cause of the motion. I then extrapolate that experience of causality from myself to the exterior.
Ratzinger says the same with regard to revelation. Until there is the experience and consciousness of going out of self to the person of the revealer, there is no revelation because there is veil removed, or no re-vel-ation. The experience of the self as image of God is part of the revelation of God to us. We must activate ourselves in our subjectivities to experience self as image, and in that activation, experience God. The major part of revelation is the activation of the self as “I am” in order to know Him who is “I AM.” Like is known by like, because ultimately knowing is being one being with another in some fashion or other.
This has been the epistemological move of modern physics. The observer introduces himself into the experiment and becomes part of it. Relativity theory and quantum mechanics became possible precisely by this insertion of the observer as part of the observed.
Hence, by necessity, with regard to the topic of unity, the subjective experience yields oneness, not unity because unity is the objectified perception of individuals, who/which stand in themselves as substances and are related accidentally. When one lives Christian faith as the moral act of self gift, one literally becomes “another Christ” and by transferring this experience to Christ, one is able to say, “You are the Christ, the Son of the living God” (Mt. 16, 15). This “becoming Christ” such that there is “neither Jew nor Greek, slave nor freedman, male nor female” because “you are all one in Christ Jesus” (Gal. 3, 28), then we are not “united” but "one." This is the depth of the Unity Octave - "that they be one as we are one" - and some of the subjacent epistemology.
 J. Ratzinger, “Milestones,” Ignatius (1998) 108.
 J. Ratzinger, “Introduction to Christianity,” Ignatius (1990) 123-124.
 J. Ratzinger, “Introduction to Christianity,” op. cit. 124.
 Owen Barfield, “Saving the Appearances,” Wesleyan University Press, (1988) 15.
 Ibid., 16-17.
 Ibid. 20-21.
 Ibid. 21.
 K. Wojotyla, “The Personal Structure of Self-Determination,” Person and Community, Lang (1993) 193.