Sense Data vs Naïve Realism
Here we have a brief overview of theories concerning perception. Sense-Data Theory suggests that we perceive mind-dependent objections of perception, whereas Naïve Realism posits that we experience and are acquainted with the real, external objects.
Sense data are defined as “mind-dependent objects that we are directly aware of in perception, and that have exactly the properties they appear to have” (Huemer, 2019). Sense Data Theory suggests that whenever an individual has a sensory experience, there is something in which they are perceptually aware of (Crane and French, 2017). In cases of illusions, the sense data that appears to us is perceived via the object as containing an appearance in which it does not possess. In cases of hallucinations, we experience a sense datum that is not in the objective world. Therefore, we do not experience a mind-independent, physical object such as a table in front of us, we experience a mind-dependent, sense datum.
Naïve realists believe that the veridical experiences involved in genuine cases of perception consist of relations to ordinary objects and that we are aware of the physical objects rather than sense data (Crane and French, 2017). In cases of normal and illusionary perception, one is acquainted with the properties that perceptually appear to us via external objects; “…the character of experience is a presentation of ordinary objects, and is immediately responsive to the character of such objects because such objects are literally involved in the experience” (Huemer, 2019).
According to Naïve Realism, the ultimate personal-level psychological explanation of the phenomenal, epistemological and behavioural features of a veridical experience is the fact that the subject perceives things in her environment (e.g. a banana) and some of their properties (e.g. its yellowness and its crescent-shapedness) (Logue, 2020, p. 2).
It is clear how Naïve Realist Theories would object to Sense Data Theories as the former states the perceptual experience of, for example, a chair is the result of the physical chair whereas the latter states that we perceptually experience a sense datum of a chair. It is the intention of this essay to argue for the latter theory through the use of practical and theoretical examples.
This essay will discuss the merits of Naïve Realist Theories and Sense Data Theories. However, what follows this is an argument for Sense Data Theory by portraying how it more succinctly accounts for the objections to Naïve Realism.
1. MERITS OF NAÏVE REALISM
A naïve perspective of perception is one of simply being aware of or in perceptual contact with the ‘everyday’ world of objects. We are able to acquire objects in our perception such as the feeling of a chair, the sound of a bird or the appearance of a car. Like Sense Data Theory, perceptual experience involves acquaintance, in that there is a constitutional relation between the object and the acquainted perceptual experience. The object ‘out there’ is presented to you. Naïve realists state what we perceive is the objective world not mind-dependent sense data (Logue, 2020; Crane and French, 2017; Beck, 2018). Most believe when we hallucinate an object, we are not acquainted with anything and therefore we are not having a perceptual experience. Instead of distinguishing between veridical and non-veridical cases, naïve realists distinguish between ‘good’ and ‘bad’ cases of perceptual experience. An individual can either perceptually experience the objective world or not. Naïve realists account for illusions by either re-describing or reducing them, appealing to cognition or imagination or utilising strategic silence. Explaining illusions by reducing or re-describing them is to describe illusions as an object in perception in which it appears in a manner that makes you believe the object has the appearances it does not hold. For example, a dress may look yellow in a specific light when in reality, it is blue. A naïve realist could explain this as an individual perceiving the objective world; how the dress looks to be in a certain light rather than an illusion. This ontological argument states that the shapes and colours of objects manifest in various contexts, i.e. the context of the light hitting the dress making it seem yellow. Appealing to cognition is another strategy in which an individual, rather than undergoing an illusion, cognises an object incorrectly via post-perceptual cognition making us believe the object is different than it really is. There are various other factors that naïve realists state influence our perception other than the undergoing of an illusion;
In the case of vision, these conditions include both extra- dermal conditions of perception (e.g., location and orientation conditions, lighting conditions), as well as conditions of the perceiver’s psychological apparatus (e.g., idiosyncrasies of her visual system, attention patterns, and cognitive processing) (Beck, 2018, p. 610).
Some Naïve Realists utilise strategic silence - there is nothing positive to say beyond the fact that illusions and hallucinations are just indistinguishable from perceptual experiences (Martin, 2006, p. 369).
Naïve realism looks promising in that it argues for the objective world being perceived, meaning the objective world is out there and we perceive it correctly in perceptual experience. “The motivation for Naïve realism that presumably gave the view its name is based on the idea that it is the common sense theory of veridical experience” (Logue, 2020, p. 3). Sense Data Theorists argue that we never perceive the objects in front of us, rather we experience what we perceive in our minds which can be disconcerting to think we never truly experience objective reality. John McDowell claims that a view along the lines of Naïve realism affords a way out of scepticism about the external world (McDowell 1982, 2008; Logue, 2020, p. 3). Having the Naive realist property explains the way visual experiences introspectively seem (Nudds, 2009, p. 335), naïve realists do not explore the possibility that the object we perceive is different to how we perceive it, therefore when we perceptually experience something, we experience it correctly in ‘good’ cases of perception. Naïve realism rejects the Common Kind Principle in which what you perceive in veridical or ‘good’ cases can also be perceived in the same manner as hallucinations or ‘bad’ cases of perception.
2. OBJECTIONS TO NAÏVE REALISM
Naïve realism argues that since total hallucinations don’t involve the subject perceiving anything in her environment, they can’t fundamentally consist in perceiving things in her environment (Logue, 2020, p. 2). This is fair, however if we are speaking, purely, about the perceptual experience, the above point does not explain how we experience hallucinations in comparison to veridical experience. Matthew Nudds (2009) makes this point effectively using a vase of flowers;
Suppose that it is possible to keep fixed the exact state of your brain when you are looking at the vase of flowers, whilst at the same time removing the vase and the flowers. Were this to happen, there would be no change that you could detect in the character of your visual experience even though you would no longer see the vase of flowers: you would be having a hallucinatory experience brought about by a state of your brain that matches (or is of the same kind as) that state which is involved in your seeing the vase (Nudds, 2009, p. 336).
According to the Causal Argument, since your brain is in the same state in both the veridical and the hallucinatory experiences, the way you perceive in both situations must be of the same kind too, thus Naïve realism is false (Nudds, 2009, p. 336). A Naïve realist might say it’s impossible for veridical experience to be indistinguishable from a dream (Roark, 2016, p. 44). We can tell the difference between a dream and waking life so how can we experience these two differently? A Sense Data Theorist could reply by stating ‘we are not saying we can’t spot the difference between a dream and normal waking life, just that it is possible for one to be indistinguishable from the other.’ I would say that it is more than possible. If we are purely speaking from an experiential standpoint, then dreams can be indistinguishable from normal, waking life. People have nightmares or do not want dreams to end precisely because they believe they are experiencing real life until they wake up.
Another point Heather Logue (2020) makes is that if our brains were wired differently, we could experience something that is objectively yellow as green.
On this view, the phenomenal character of my experience is determined by something that isn’t determined by the properties I perceive—namely, a quale connected to yellowness only by the contingent fact that it happens to represent yellowness (Logue, 2020, p. 4)
It seems Logue is proving the opposite point I assume she is trying to make, in that if our brains were wired differently, we would experience the world differently to how it objectively is. Therefore, how do we know that what we experience right now is the objective world? Surely, this is an argument for Sense Data Theory. Experiencing the world as differently to how it objectively is due to the alteration of how our brains are wired would be a ‘bad’ case of perception according to naïve realists. How can this be disregarded as a ‘bad’ case when we would experience this in the same manner as if we were experiencing the objective world?
Logue argues further that the phenomenal character of veridical experiences of at least some sorts of properties can afford at least partial knowledge of what things are like independently of experience (Logue, 2020, p. 16). However it fails to account for how naïve realism can explain ‘bad’ cases of experience like hallucinations and illusions. It can be suggested that the Naïve realist is forced to accept the conclusion that “whatever the most specific kind of mental event that is produced when having a causally matching hallucination, that same kind of event occurs when having a veridical perception” (Martin 2006, p. 369; Nudds, 2009). Since there is nothing inconsistent with the idea that a veridical, perceptual experience can be an instance of both veridical and hallucinatory experience, the conclusion above is not inconsistent with naïve realism, but it does threaten the motivation for accepting it (Nudds, 2009, p. 337).
Another objection to naïve realism is the idea that not everything we perceive from the external, real world is perceived as physical or ‘material’ like thoughts. How does the naïve realist explain thoughts? Are they simply ‘bad’ cases of perception because they are not physical or strictly material? We perceive our thoughts every second, so this sounds implausible. Whilst a lot of objects have physical aspects, very few fit ideally into the concept of a ‘material thing’ (Austin and Warnock, 1979, p. 8).
3. SENSE DATA THEORY
Sense Data Theory, on the other hand, accepts the Common Kind Principle and the premise that we experience ‘good’ and ‘bad’ cases (veridical/non-veridical) of experience in the same manner.
Sense Data Theory therefore is able to explain how we experience hallucinations and illusions as well as veridical experience, whereas naïve realism fails to do this effectively. In the case above where our brains are wired to experience yellow objects as green and green objects as yellow, it seems more likely that what we are experiencing is mind-dependent sense data and not the objective world. An objection to this may be; how can a Sense Data Theorist be sure that what he experiences is the objective world (Huemer, 2019)? To that I would say, I don’t. I am fairly sure that what I am experiencing when perceiving sense data is a reliable representation of the real world but I can’t be 100 percent. We clearly would not be experiencing the true objective world so what are we experiencing, if not mind-dependent sense data?
If we were to live our entire lives, unbeknownst to us, with coloured lenses permanently installed in our eyes in which we see the world as rose tinted, then we were to suddenly realise and uninstall the lenses and we then see the world for what it is, what difference, experientially is this to hallucinating the world as all rose tinted due to a hallucinatory drug? The experience of seeing the rose tinted world and the objective world is experienced in the same manner. Naïve realism would account for this by stating that the former experience is a ‘bad’ case of perception and the latter is a ‘good’ case. This does not seem plausible, however, as both these experiences were indistinguishable until the realisation of the lenses, so experientially it does not seem plausible to say these experiences are perceived differently.
Lastly, Sense Data Theory can account for non-physical/material objects of perception by stating that all objects of perception are non-physical/material. This accounts for thoughts and appearances in consciousness. Consciousness is subjective and to be conscious is what it is like to be conscious and something is perceived if there is something that it is like to perceive it (Nagel, 1974 p. 436; Van Gulick, 2018; Harris, 2011). Whatever else consciousness may or may not be in physical/material terms, the difference between it and unconsciousness is first and foremost a matter of subjective experience (Harris, 2011). If consciousness is subjective and the appearances in consciousness such as sights, sounds, thoughts and so on are not objective and a matter of how we perceive rather than what we perceive, then we do not experience the objective world, either we are conscious or not. There is no evidence that consciousness exists in the physical world (Harris, 2011), therefore the idea that everything we perceive is physical does not account for consciousness and thus, naïve realism does not account for consciousness. Although consciousness, it can be argued, “…is the one thing in this universe that cannot be an illusion,” (Harris, 2011) and is objectively a reality, it’s contents are not.
“When we hallucinate, our experience does not present any objects or features, it purports to present them” (Nudds, 2009, p. 342): it is for us as if some object is there, whereas in veridical experience we perceive an object that is presented to us, that is in the objective world. What we perceive in consciousness is presented to us. We perceive a noise that is presented to us just like we would perceive a hallucination of a noise that is presented to us. The only difference here is that one was the result of the objective world, the other the result of a hallucinogenic drug perhaps. The only difference is if an object is out there or not, our experience in both is the same; “attending to what one’s experience is like cannot be separated from exploiting and attending to the features of the world as purportedly perceived” (Nudds, 2009, p. 342). “‘If it is true of someone that it seems to them as if things seem a certain way, as if they are having a certain sense experience, then they are thereby having that experience’(Martin 2006: 397); but the connection is an epistemic rather than a metaphysical one” (Nudds, p. 342).
Therefore the below premises summarise the arguments made above;
1. Sense Data Theory posits that we experience veridical perception, hallucinations and illusions in the same manner
2. Naïve realism posits we experience the objective world in ‘good’ cases of perception
3. Naïve realism posits hallucinations and dreams are ‘bad’ cases of perception and are therefore redescribed
4. Naïve realism avoids skepticism of the objective world and states we experience the objective world correctly
5. Naïve realism cannot account for how we perceive ‘good’ and ‘bad’ cases of perception
6. Sense Data Theory accounts for the subjectivity of consciousness and the objectivity of the real world – the best of both worlds
7. Therefore, Sense Data Theory is more effective at accounting for how we experience veridical and non-veridical perceptions
4. CONCLUDING REMARKS
Although naïve realism avoids skepticism of the objective world and accounts for how we perceive objects of perception that are in the real world, it cannot account for the specificity of how we experience hallucinations. Disregarding them as ‘bad’ cases of perception does not explain how we experience them.
Sense Data Theory accounts for both by stating we experience veridical and non-veridical perceptions in the same manner. This can lead to skepticism of the objective world, however it’s more plausible than experiencing the two in different manners. This was shown via practical examples such as the rose-tinted lenses example and the mis-wiring of our brains. It’s much more likely that what we experience when perceiving something that is not there is mind-dependent and experienced in the same manner as something that is there but that is also mind- dependent.