15. Fifteen Lecture: Further Explanation of Perceptions
In this lecture, I present a step-by-step analysis of how we understand the world in our everyday lives. Many students have remarked that it changes the way they perceive the experience of living, often initiating significant self-reflection. We explore how the pure forms of intuition and the categories of understanding are applied to transform noumena into phenomena, which are then subsumed under a concept to make a judgment. This pivotal lecture frequently alters one's perspective, creating an insight that cannot easily be "unseen."
Many authors have claimed that Kant's use of the term perception is somewhat inconsistent. However, the meaning of perception becomes much clearer (and Kant’s consistency becomes evident) when we understand that Kant explains the same concept by approaching it from different perspectives.
Perception as appearance combined with consciousness
Kant states that "appearance combined with consciousness is called perception" or, more specifically, that "perception is the consciousness of an appearance (before any concept)."
According to Kant, appearances are representations of objects from the external world created by our sensibility or the productive presentations of our imagination. In both cases, we have an appearance of a thing-in-itself in our mind, with which we can operate and attempt to create a cognitive experience. Thus, Kant refers to appearances as "data for a possible experience."
However, to recognize an appearance and integrate it into our experience, we need consciousness to create a perception. More specifically, we require both pure (transcendental) consciousness (or pure apperception) to use forms of intuition and empirical apperception (inner sense) to recognize appearance as our subjective perception. Without self-consciousness, we would not recognize an appearance (we could not distinguish it from ourselves or connect it to our understanding).
Additionally, perception is something we can connect to concepts, but it is not yet conceptualized. Instead, it serves as a foundation for forming concepts based on our experiences with appearances.
Example 1
We encounter a leather armchair in a room (noumenon). Through our senses, we receive sensations and create an appearance of the object in our mind (phenomenon) using pure forms of intuition (space, time) and pure concepts (categories of understanding). We recognize it as our appearance (through consciousness), and this appearance becomes a perception of an object in the room. At this stage, we do not yet have cognition of it, but we have perceived it as the content of sensation in our consciousness. However, finally, judgment occurs when the understanding subsumes this perception under a concept, allowing us to recognize and affirm, "This is a leather armchair."
Example 1 as Stages of Perception and Cognition:
1. Encountering the Noumenon. We encounter the leather armchair as a noumenon, an object existing independently of our perception, which cannot be directly known.
2. Receiving Sensations. Through our senses, we receive raw sensory data from the object.
3. Forming the Phenomenon. Using the pure forms of intuition (space and time), we structure the sensory input, creating an appearance of the object in our mind (phenomenon).
4. Applying the Categories of Understanding. The raw appearance is organized using pure concepts (categories of understanding), which provide a framework for interpreting the data as a coherent experience.
5. Recognizing the Appearance through Consciousness. We become aware of the phenomenon as our appearance through consciousness, situating it within our subjective experience.
6. Perceiving the Object. The appearance becomes a perception of an object in the room, identified as the content of sensation within our consciousness. At this stage, we perceive the object but lack cognition of it.
7. Making a Judgment. The understanding actively subsumes the perception under a concept (e.g., "leather armchair"), allowing us to form a judgment. This act integrates intuition and concept, resulting in cognition and the affirmation, "This is a leather armchair."
Example 2
We are in an empty room and consider filling it with something. Our imagination combines existing concepts with our forms of intuition (space and time), and we form an appearance of how the space would look if we placed something in it (e.g., furniture, a wall, or any interior object). Since we are not imagining a specific object in a particular category, we attribute the "filled space" in the room to an object in general. As this appearance is grounded in our consciousness (we own this appearance), it becomes a perception of the room as partially filled.
Perception as part of cognition
Kant states: "things in space and time, however, are only given insofar as they are perceptions (representations accompanied with sensation), hence through empirical representation."
When we receive sensory input from an object (noumenon) and recognize it through our intuition (with consciousness), we have a perception of the thing-in-itself (appearance). At that point, we do not yet have a complete cognition of what it is; it remains "a thing in a room." However, once we can place that perception under an existing empirical concept, we gain a cognition of the object through our understanding.
Example
We see a leather armchair in the room. Sensations give rise to an appearance, which, when recognized through consciousness, becomes a perception. The fact that we almost instantly identify it as a leather armchair shows that our mind has synthesized this perception with existing concepts through the categories of understanding, allowing us to place it under the broader concept of "chair" and the specific sub-concept of "leather armchair."
Kant emphasizes that perception without empirical categories would not provide cognition, just as empty categories without intuition would not produce a concept. Thus, he states: "Categories consequently have no other use for the cognition of things except insofar as these are taken as objects of possible experience."
Remark
That is also what separates us from animals. A dog sees a concrete tree as an empirical intuition (creates a perception) and may recognize it as a tree-like object. However, it cannot form a cognition of "tree" as an abstract concept. Humans, by contrast, can subsume perceptions under abstract concepts using the categories of understanding, allowing us to conceptualize "tree" as encompassing diverse instances, from bonsais to Giant sequoias.
Perception as empirical consciousness with a sensation
Perception also allows us to anticipate sensations without knowing their precise intensity, as "a matter of perception." Kant explains that through anticipation, we can "cognize and determine a priori what belongs to empirical cognition." However, the magnitude of sensation can range "from its beginning, the pure intuition = 0, to any arbitrary magnitude."
Our "understanding can anticipate a synthetic proposition of the sort concerning the degree of everything real in appearance." Here, "real" in appearance refers to the strength of the content (intensive magnitude) of the specific empirical experience derived from the sensation of an object. This contrasts with the extensive magnitude, which pertains to the form of sensation as the pure forms of intuition—space and time.
The intensive magnitude of sensation forms a continuum from 0 to the highest perceivable degree. However, we cannot evaluate its precise magnitude a priori; experience is necessary for that.
Example
When encountering a new leather armchair, we can anticipate perceptions of its softness, solidity, or weight. However, we cannot determine their exact magnitude until we interact with it—for example, by sitting on it, lifting it, or touching its material. In this way, perception as empirical consciousness with sensations allows us to anticipate the spatial and temporal structure of things (extensive magnitude) while requiring experience to determine the exact degree of sensation (intensive magnitude).
In some cases, Kant uses the term "perception" in ways that seem to blur the lines with sensation. For example, when he states that "cognizing the actuality of things requires perception, thus the sensation of which one is conscious" (KV 325) or that "perception that refers to the subject as a modification of its state is a sensation" (KV 398), it might lead one to equate perception with sensation.
However, a closer analysis reveals that Kant underscores the necessity of perception, which integrates sensations, for cognition. Sensation alone provides the raw material of experience but does not create knowledge. Likewise, pure concepts without sensory input remain empty. Perception bridges this gap, combining sensation with the forms of intuition (space and time) and the categories of understanding to make cognition possible. Thus, while perception contains sensations, it transcends them by structuring and unifying them in a way that enables knowledge.
Nihil privativum and ens imaginarium
Kant also states, “cognition of objects can be generated from perceptions, either through a mere play of imagination or by means of experience” (KV 429). Thus, even in cases of initially unclassifiable phenomena, our cognitive faculties can potentially generate knowledge by synthesizing perceptions through these a priori forms and categories.
Nihil privativum refers to the absence or lack of a particular quality or characteristic in an otherwise existing object—what Kant terms relative nothingness. For example, the absence of color in a black-and-white photograph illustrates this concept, where the object exists but lacks a specific property.
Ens imaginarium, by contrast, refers to an empty intuition without a concept. For example, encountering a human-sized talking fish would likely elude categorization under any existing conceptual framework. Such beings may exist only in our imagination and be registered under a subjective imaginary category. However, Kant emphasizes that the inability to conceptualize something at first does not mean we cannot eventually do so. Cognitions arise from two principal sources: sensory input or existing concepts. Both require the inherent forms of intuition (space and time) and the categories of understanding to structure experience.
Thus, according to Kant, sensation and perception are different aspects of our experience. Sensations are components of perception that perception processes and organizes to enable us to make sense of the world.
Let us not dismiss the possibility of encountering a human-sized talking fish that we cannot categorize under any existing concept so quickly. The fact that we might initially be unable to conceptualize it does not mean we would never be able to do so. Cognition can be generated by the mind from two fundamentally different sources: sensory input or existing concepts. In both cases, cognition requires the mediation of our inherent forms of intuition (time and space) and the categories of understanding. As Kant states, “cognition of objects can be generated from perceptions, either through a mere play of imagination or by means of experience”.
Regarding the formation of cognition, it must involve two “sides”: receptivity (as intuition) and spontaneity (as understanding). This is where the imagination plays a crucial role. Imagination cannot be strictly classified as belonging exclusively to either side, as it cooperates with both. When sensory input forms the basis of perception, imagination functions as reproductive sensibility, allowing objects we encounter in the external world to be re-presented in our minds. Conversely, when forming perceptions without sensory input, imagination operates as productive spontaneity, combining existing concepts into new images in our minds. Thus, imagination bridges intuition and understanding, fulfilling the criteria required for cognition.
Imagined perceptions can be utilized in much the same way as perceptions derived from sensations. Consequently, some of our ideas may present us with things we can imagine but never experience in the real world. When Kant states that “a concept made up of notions [other concepts originating from understanding only, with no sensory input], which goes beyond the possibility of experience, is an idea or a concept of reason”, he refers to this capacity of the mind. While imagined perceptions do not provide direct empirical knowledge, they can function analogously to perceptions from sensory input, expanding the boundaries of what we can conceptualize.
In the case of a human-sized talking fish, Kant’s framework would classify it, initially, as an empty intuition without a concept (ens imaginarium), rendering it "nothing" as an object of the empirical world. However, once we create the necessary concepts to classify this creature of our imagination, it can be integrated into our cognition as an idea. Thus, imagination enables us to transition from mere fantasy to a structured concept within the realm of thought.
