Introduction
In our last lesson, we examined Merleau-Ponty's analysis of depth perception. We saw how he rejected the classical idea that depth is an intellectual construction based on two-dimensional data. Instead, he argued that depth is the most fundamental dimension of our lived experience, the very expression of our body's immersion in the world. This established a key theme: perception for Merleau-Ponty is a unified, embodied engagement, not a piecemeal reconstruction by a detached mind.
Today, we will deepen this understanding by exploring the phenomenon of synaesthesia. Our goal is to explain the significance of synaesthesia in Merleau-Ponty's unified theory of perception. Classically, synaesthesia—such as seeing colours when hearing music—is treated as a rare neurological quirk, a "crossing of wires." For Merleau-Ponty, however, it is a crucial piece of evidence that reveals the true, underlying nature of all perception. We will uncover why he argues that this "sensing-together" is not the exception, but the rule.
1. The Classical Model: The Senses as Silos
To appreciate the radical nature of Merleau-Ponty's position, we must first understand the tradition he is arguing against. This view, with roots in Descartes, treats the senses as separate, independent channels. Vision provides colours and shapes, hearing provides sounds, touch provides textures, and so on. These data streams are distinct and do not communicate with each other directly.
How, then, do we experience a coherent, multisensory world? The classical answer posits a higher-level coordinating faculty, what Descartes called the sensus communis or "common sense." This is imagined as a central processing unit in the mind or brain that receives the disparate reports from the senses and synthesizes them into a single, unified object or experience.
The following reading explains this Cartesian framework, which provides the essential background for Merleau-Ponty's critique.
[PDF] Music Theatre and Intersensoriality (after Merleau-Ponty)
This excerpt from Jonathan De Souza's paper, 'Music Theatre and Intersensoriality', clearly outlines the Cartesian view of the senses that Merleau-Ponty dismantles.
Please read the first four paragraphs of the article, starting from 'When the philosopher Maurice Merleau-Ponty died...' and ending with '...where independent streams of visual, auditory, and other sensory data would be integrated.' As you read, focus on this key idea: for Descartes, the senses are separate and require a central 'common sense' (located in the pineal gland) to unify their data.
In this model, the unity of perception is a secondary achievement of the intellect. The body delivers fragmented data; the mind puts it together.
2. Merleau-Ponty's Alternative: Intersensoriality
Merleau-Ponty rejects this picture entirely. He argues that the unity of the senses is not a problem to be solved by the intellect because the senses are never separate in the first place. They are unified from the very beginning at the level of the lived body.
Instead of a central sensus communis, Merleau-Ponty proposes a principle of intersensoriality. The senses belong to a single, knowing organism and are always already in communication with one another. They form a dynamic, integrated system.
The next part of the same article explains this crucial counter-argument.
[PDF] Music Theatre and Intersensoriality (after Merleau-Ponty)
Continuing with De Souza's paper, this section presents Merleau-Ponty's concept of 'intersensoriality' as a direct challenge to the Cartesian model.
Please read the next three paragraphs, starting from 'For Merleau-Ponty, by contrast...' and ending with '...the notes in a chord.' Focus on the central claim, beautifully captured in this quote from Merleau-Ponty: 'The senses translate each other without the need for an interpreter; they understand each other without having to pass through the idea.'
As De Souza highlights, Merleau-Ponty argues that our senses "harmonize" like notes in a chord. Each contributes its unique quality, but they function together to create a single, indivisible whole. This means that sensing is, by its very nature, a form of syn-esthesia: a "sensing-together." We don't have five senses that get combined; we have one body that senses the world in five different ways, and these ways are intrinsically linked.
3. Synaesthesia: The Rule, Not the Exception
From this perspective, the phenomenon we call synaesthesia is not an anomaly. It is simply a moment where the normally tacit, background unity of the senses becomes explicit.
Merleau-Ponty argues that synaesthetic perception is the rule. We experience it constantly, but we have been trained by "scientific knowledge" to ignore it. We learn that eyes are for seeing and ears are for hearing, and we begin to parse our experience into these clean, abstract categories, thereby losing touch with the rich, intermingled reality of perception.
The following reading develops this argument in detail, using synaesthesia as the key piece of evidence against the classical view of sensation.
[PDF] Merleau-Ponty and McLuhan on the Modalities of Perception
In this excerpt from the paper 'Merleau-Ponty and McLuhan on the Modalities of Perception' by Leon-Carlyle, you will see the core of Merleau-Ponty's argument: that synaesthesia reveals the normal, primordial state of perception.
Please read two short sections from this paper. First, read the final paragraph of the first page (starting with 'Like the experience of the sensible quality...'). This sets the stage by showing that isolating a single sense requires an 'abnormal attitude'. Then, read the first three paragraphs of the following page, which directly address synaesthesia (starting with 'With this ambiguity...' and ending with '...conceived by the physicist.'). \nPay close attention to the crucial conclusion Merleau-Ponty draws: 'Synesthetic perception is the rule and, if we do not notice it, this is because scientific knowledge displaces experience and we have unlearned seeing, hearing, and sensing in general...'
This is the heart of the matter. Merleau-Ponty is not just describing a curious phenomenon. He is using it to perform a phenomenological critique. The scientific account, which defines vision by the "visual quale" (the specific quality of sight) and sound by the "sonorous quale," is an abstraction that makes the lived reality of synaesthesia literally "meaningless." For Merleau-Ponty, if our definitions conflict with the phenomenon, it is the definitions that must change, not the experience that must be dismissed.
Think of these everyday examples that reflect this deep intersensory unity:
- We perceive the coldness of a blue light or the warmth of a red one.
- We hear the sharpness of a piccolo or the roundness of a cello's tone.
- We see the softness of a fabric or the brittleness of glass without having to touch them.
- As Merleau-Ponty notes, the painter Cézanne claimed we can even see an object's odor.
In each case, a quality we typically associate with one sense (temperature, shape, texture) is immediately present in the experience of another. This isn't a rational deduction; it's a direct perception.
Conclusion
Today we've explored how synaesthesia functions as a cornerstone of Merleau-Ponty's unified theory of perception. Far from being a fringe case, it serves as the key that unlocks the fundamental structure of our sensory life.
Key Takeaways:
- The classical/Cartesian model posits five separate senses whose data must be synthesized by a higher-level intellectual faculty, the
sensus communis. - Merleau-Ponty counters with the concept of intersensoriality: the senses are already unified at the level of the lived body and "translate each other without an interpreter."
- Synaesthesia is therefore not an anomaly but the rule of perception. It makes explicit the constant, background communication between our senses.
- We tend not to notice this unity because scientific education teaches us to think in terms of abstract, separate sensory channels, causing us to "unlearn" our primary, unified experience.
- The significance of this argument is profound: it serves as a powerful critique of mind-body dualism and reinforces the primacy of a holistic, embodied perception over abstract, intellectual reconstruction.
Preview of the Next Lesson:
Having established the unity of the senses, we will turn to the world they perceive. In the next lesson, we will explore Merleau-Ponty's crucial distinction between 'lived space' and 'geometric space'. You will see how the abstract, measurable grid of geometry is a second-order construction derived from our primary, qualitative experience of a space organized around our body's capabilities.