The fifth book of Husserl’s LI serves primarily as a preliminary to the sixth book, which is more directly concerned with providing a phenomenological theory of knowledge. As stated at the opening of the fifth book, meaning and objectivity, central to all scientific activity, are essentially brought about in or through intentional acts of consciousness. Husserl further maintains that so-called signitive or meaning acts (these are synonymous) can be verified or justified if they are fulfilled by intuitive acts upon coinciding with them. But in order to understand how that works, a more general account of intentionality is first needed. That is to say, Husserl needs a framework for thinking about how consciousness comports itself to things in general, and this is what the fifth book provides some first steps toward.
Intentional experience, Husserl notes, is an ‘important class within the sphere of psychic experiences’ (Husserl 1984, 353). This implies that intentionality is not exhaustive of consciousness as a whole. It rather captures that essential part of our lives through which things are given to us.Footnote 19 Every intentional experience involves something that is given, in other words, it involves representation—a concept which does not denote any mediation of experience for Husserl, but rather only the presentation of ‘something over-against.’ The concept of intentional experience is further terminologically equated with the concept of act. This means that when in LI Husserl speaks of acts of consciousness, he speaks of intentionality, and vice versa (this also goes for his later works).
It is typical of the Husserl of LI to identify phenomenological consciousness with all that is ‘really’ (reell)Footnote 20 inherent in consciousness. On account of LI, all the different types of acts—of consciousness’s comportment toward things—belong to the study of consciousness. The object to which an act is related is, however, not considered a part of the act, and likewise does not belong to the study of intentionality (Husserl 1984, 358, 427). The act-structure is said to contain, among others, the appearance of the thing (Husserl 1984, 360–361). The object itself, by contrast, is not a part of it. The conflation of these distinct matters—of the thing-appearance and the appearing thing—is what, according to Husserl, troubled phenomenalists such as Berkeley (Husserl 1984, 370–371). The phenomenologist, then, investigates only the act-appearance structure as a distinct subject matter of its own, while disregarding the object in terms of its empirically real structures.
Husserl thinks there are many different ways in which we can be intentionally directed at things. The same object can be the target of different types of acts, as in judging, seeing, remembering, or wishing for the same state of affairs. In LI, Husserl exploits these differences in terms of act-quality. The act-quality can be characterized generally as the way of intending something. So in perceiving or wishing for a cup of coffee on one’s desk, different act-qualities establish the same object-relation in different ways.
From section 16 of the fifth book onwards, Husserl introduces another element into the intentional structure, which functions as counterpart to the act-quality: the so-called matter. The matter combined with the quality are said to constitute the intentional essence: that which any intentional act has—although it does not exhaust the complete epistemic essence of an act, which can be postponed until later.
The notion of matter, on Husserl’s account, helps accounting for the fact that we can intend the same object in different ways. For instance, in seeing or wishing for the same object, different act-qualities are said to correspond to one matter. Husserl, then, seems to suggest that (i) matter determines object-reference, but also that (ii) the same object-reference implies the same matter. In other words, to say that we can perceive and imagine the same object in different ways amounts to saying that there can be different acts with the same matter.Footnote 21
Yet this does not seem to be Husserl’s view exactly. For Husserl also remarks that it is possible for acts to intend the same object while having different matters (Husserl 1984, 497). This implies that the concept of matter is wider than the determination of object-reference—since one object-reference can involve different matters. This, in turn, means the second clause stated above cannot be true after all; the same object-directedness does not yet imply the same matter. The judgments ‘Elvis Presley was born in Mississippi’ and ‘the King of Rock and Roll was born in Mississippi’ have the same object-reference, but a different matter—a difference not accounted for by difference in quality (both are assertions). On the one hand, then, Husserl exploits the concept of matter to account for identical object-reference over various act-qualities, but he also uses it in a wider (Fregean) sense to include exactly how object-reference is determined, thereby allowing different matters for one object-relation (Husserl 1984, 429–430, 497).
So far, the fifth book has prepared for Husserl’s theory of knowledge in the sixth book by introducing a basic repertoire of distinctions pertaining to intentional consciousness. The most important of these were the act-quality and the act-matter—which together constituting the intentional essence—and the intentional object, which is not a part of the act. While these concepts should allow us to understand the fundamental ways in which consciousness can relate to objects, Husserl does not think they suffice to clarify the phenomenological operations of acquiring and justifying knowledge. This process, central to the sixth book, is captured with the term ‘fulfillment’ (Erfühlung). The account of fulfillment simultaneously entails the core of Husserl’s critique of Kant, namely of the idea (i) that knowledge or justified belief necessarily involves a cooperation of two faculties.
To account for the acquisition and justification of knowledge, the sixth book introduces another crucial distinction within the class of intentional acts. This is referred to as the interpretative form of acts (Husserl 1984, 624), of which Husserl distinguishes two kinds: signitive and intuitive ones. This means that acts can now be classified as either signitive or intuitive (or a mix between both), while all of them in turn have a quality and a matter. The new distinction is of great importance, since, as Husserl notes, all knowledge refers to the relation between signitive and intuitive acts (Husserl 1984, 736). Moreover, it serves, in a way, to replace the Kantian separation of understanding and sensibility.
It is crucial that on Husserl’s account signitive acts alone can be defined as meaning (Bedeutung) acts. That is to say, signitive acts are intentional acts which express or give voice to meaning. In the first sections of the sixth book, Husserl puts considerable effort in showing that the meaning of an expressing act is always contained in special signitive acts—which are ‘founded’ acts—and never, for instance, in a simple ‘founding’ act of seeing. To sustain this, he offers elaborate discussions of what we today would call demonstrative reference, where the ‘place’ of the expressed meaning is arguably most difficult to decide. In a demonstrative reference, as in seeing and subsequently expressing ‘this is a blackbird,’ we have a judgment act tied directly to a perceptual content at which it is directed. In short, Husserl accepts that the perceptual act supplies the meaning act with object-directedness, but he denies that it contains the act of meaning (Husserl 1984, 554). As Husserl puts it, ‘when I say this, I do not plainly perceive; instead, on the basis of seeing a new act builds itself, which directs itself to it and […] which is dependent upon it, namely the act of meaning-this’ (Husserl 1984, 554 my italics). Although this new meaning act is built onto the perception, it could principally do without it (Husserl 1984, 556), which should prove that the expressed meaning is not ‘in’ the perceptual act.
Husserl thus separates the pure act of meaning or expressing something from (in this example) the concrete act of seeing. The latter here provides all the richness of content; the former only the act of expression. For this reason, Husserl can refer to the act of meaning as principally a completely empty act (Husserl 1984, 607). To be sure, meaning acts are in reality rarely completely empty. If, for instance, someone would shout, ‘Look out the window!’ and you would do so without seeing anything remarkable, you would have an empty meaning intention which awaits the fulfillment only the perception of something peculiar could give. Yet this empty intention already operates with a tacit scope of possible adequately fulfilling acts—for instance, things with a sufficient degree of peculiarity—which means the meaning act was not completely empty after all.Footnote 22
The emptiness of meaning acts becomes clearer by contrasting it to the complete class of intuitive acts. The class of intuitive acts, on Husserl’s view, includes all acts that are capable of giving fullness to empty meaning acts. Fullness here is best understood very generally as giving something. The prime example of an intuitive act is a simple perception. While a simple perception can certainly share object-reference with a meaning expressing act, the former nevertheless seems to involve a certain surplus which the expression lacks. This peculiar surplus is, Husserl notes, the fullness or representative content intuitive acts have. The fullness is thus not an act itself, but an act-moment next to the quality and matter. It is because of the fullness of intuitive acts that we say that through them we grasp the intended thing; we behold it, rather than having a mere empty expression of it.
Simple perception is the canonical example of an intuitive act. Because of that, it may now seem tempting to understand the moment of fullness of intuition as the plain result of the sensory content involved in perception. Intuition could then be understood as letting us behold the object simply because sensations put us in real contact with it. This seems to be the case on Kant’s account, where sensibility produces an intuitive representation of an object on ground of being affected.Footnote 23
But fullness, on Husserl’s account, is not due to a sensory contact of a faculty of intuition to empirical reality. In fact, on Husserl’s account, fullness or representative content is not exclusively a moment of acts of sensible intuition. We also have it, among others, in memory. An act of remembering, on Husserl’s view, likewise involves an intention which goes out and grasps something in degrees of fullness. For instance, if I try to remember the town I grew up in, I grasp it imaginatively; I ‘see’ buildings from this or that side; I imaginatively wander the streets, and so on. I can ask myself what color this or that building used to be, and subsequently grasp that color with intuitive evidence. To be sure, the evidence I thus attain is not the same as of perceptual intentionality; only the latter has the character of giving the real thing; it peculiarly claims to stand in need of no further fulfillment (Husserl 1984, 589).Footnote 24 Yet certain non-sensible acts, Husserl insists, are capable of providing fullness to a corresponding meaning act (Husserl 1984, 646–647). Given that the capacity to provide fullness to meaning acts defines intuitive acts in general, Husserl thinks memory can be called a type of intuition.
However, according to Husserl, closer scrutiny reveals that memory and perception together cannot provide fullness to all types of meaning acts we are familiar with. One can, for instance, have an empty meaning intention of a state of affairs or a mathematical formula without thereby grasping it, beholding the sense of the proposition itself in immediate proximity. One can express, say, the Pythagorean Theorem without having an intuition in the sense of an act which gives the sense expressed, that is, grasps its meaning (Husserl 1984, 690–691). Clearly, this intuition of the Pythagorean Theorem cannot be of a sensible kind. Ideal objects cannot be seen with the senses; only their symbolically representing signs can. Yet acts expressive of ideal objects can achieve fullness. We have, therefore, according to Husserl, acts which can legitimately be called intellectual intuitions: acts which give us ideal objectivities that provide fullness to empty meaning acts.Footnote 25
Something similar is said to hold for the intuition of states of affairs. According to Husserl, simple perception does not give us states of affairs; it only gives us objects—a view he consistently maintained and elaborated in later works. If we think of the state of affairs ‘A is B,’ or ‘either A or B,’ what shows in simple perception is ‘A’ and ‘B’ in each case. However, their relation—the ‘is’ and ‘or’—cannot be intuited in simply perception. For Husserl, then, simple perception is incapable of providing fullness to categorial meaning intentions, since the relevant categorial relations cannot be simply seen.
To be sure, it would be phenomenologically inapt to suggest that simple perception gives us only completely isolated objects. Things always appear as standing in certain relations to other things. But what matters is that, Husserl claims, simple perception differs from categorial intuition in offering an immediate, effortless grasp of the thing, as in a ‘single blow’ (Husserl 1984, 674).Footnote 26 We cannot, by contrast, effortlessly grasp the state of affairs ‘that the mug is on the table,’ or ‘that the mug and the pen are black.’ Explicating categorial relations such as ‘being’ and ‘conjunction’ demands a new, higher-order, indeed intellectual act. Since categorial forms are not sensibly given, Husserl conceives of them and of universals alike as ‘objects’ of a new sort, a kind of strictly ‘super-sensuous’ objects (Husserl 1984, 673).
Perceptual, categorial, and universal intuition are perhaps the most important classes of intuition. Husserl believes, however, that they can be unified into a single theory of knowledge because they share a single common feature: the distinction between empty and full acts applies to all of them. All these acts, Husserl notes, have a unique epistemic essence (Husserl 1984, 626) comprising of the matter, quality (together the intentional essence), and the moment of fullness of the intuitive act. For any judgment—by itself an empty meaning act—to find its intuitive warrant, it is necessary that it is brought together into a single conscious experience with an appropriate act providing fullness. Hence the justification of a judgment is, Husserl maintains, experienced as a kind of coincidence between these two acts. In such a coincidence, the fullness of the intuitive act ‘fulfills’ the empty meaning act—hence the term synthesis of fulfillment.Footnote 27
Because there are so many types of act-appearance relations, there are also many different kinds of fulfillment—both in theoretical and practical domains. The concept of fulfillment applies, for instance, in having the expectation to hear a certain song played on the radio. Here, one executes an empty anticipatory act which can be fulfilled only by hearing that particular song being played. Likewise, in looking around the house for one’s car keys, one may consciously entertain an empty thought of the keys which awaits the satisfaction only a synthesis with a perceptual act of those keys could give. In a more theoretical setting, we can imagine one struggling to understand a particular technical notion in the work of a philosopher. Here, one experiences an (to an indefinite degree) empty meaning intention of the relevant concept, which awaits fulfillment through the intellectual intuition of its meaning.
Generally speaking, if the right intuition is successfully brought into coincidence with the meaning intention, the latter finds its evidence in the former.Footnote 28 Husserl acknowledges that there are various levels of such evidence, of better and worse intuitive warrant (Husserl 1984, 650–651), and a variety of both contingent and necessary factors may determine this.Footnote 29 In the ideal case of so-called adequate givenness, however, ‘the object meant is in the strict sense given in our intuition, and given as just what we think and call it’ (Husserl 1984, 648).Footnote 30 Adequate givenness, then, as a perfect synthesis of coincidence, is the equivalent of perfect correspondence of thought and object (Husserl 1984, 648).
To summarize: by focusing on the essential class of intentional acts of consciousness, Husserl first distinguishes quality from matter. In the subsequent investigation, Husserl claims that some acts are empty signifying acts, whereas others are characterized by providing intuitive fullness. This depends on the act’s additional quality of having fullness. This way, Husserl can subsequently specify epistemic justification as the fullness provided by any type of intuitive act to a meaning act, a process aptly referred to as a synthesis of fulfillment.