Before I start, it's important to address that in certain circles sensation and perception are defined as two distinct concepts. Sensation is the raw data as extrapolated by one of your (more than five) senses. Perception is the cognitive interpretation of the raw sense data. When I use either word, this is the context in which I'm using it.
Naive Realism is the idea that through perception humans experience reality as it exists independently of any observer. This argument doesn't include the cognitively atypical, namely those who experience clinically defined hallucinations. Rather, it is suggesting that the cognitive experience of a psychologically typical individual is equivalent to what is real. To a lot of people this may seem like common sense and entirely uncontroversial. However, as with most things I've ever experienced, the moment you look a little closer the more complex it becomes. As some thinkers are want to do, I don't think that imperfect perception is grounds for acting like nothing is knowable or experiential. Just because it can be easily demonstrated that human perception doesn't perfectly map to reality, I find it entirely impractical to suggest that all perception is subjective.
Things I Like About Naive Realism
I don't disagree with all the ideas that get lumped under the label naive realism. While I don't find the entire concept tenable, I don't want anyone to misunderstand me and think I'm advocating that every aspect should be put aside as disproved.
I agree with David Chalmers position that often disagreements can hinge on a single contentious term. Chalmers suggested that two parties in disagreement may find that by unpacking how they are each using a word/phrase they may find that any dispute was simply a miscommunication. While I take every opportunity to talk about the different ways individuals use language, I mention it this time to specifically draw attention to the point that not everyone uses the label naive realism identically.
I believe that when some people use naive realism, they are using it as a catch all for the idea that what is perceived through the senses is actually a quantifiable phenomena that would exist without observation. When a typical observer looks at a red chair, the redness of the chair doesn't necessarily exist outside of an observer. But, by using the duck test we can assume that the way in which light interacts with the molecular structure of the chair to reflect certain wavelengths will be consistent regardless of if an individual is there to label the phenomena. Red is the perception, the cognitive shorthand consciousness is attributing to the raw sense data. This I can get behind. If the majority of observers agree that the chair is red, then I am 100% on board with calling that chair red. If an individual wants to debate the nuances between burgundy and carmine, that's also fine by me. As long as we both understand that we're using imperfect language to communicate a perceptual abstraction to each other. It's not necessarily a pointless distinction; there may be cases where the shade of red is interesting and relevant to define. I simply fail to see the utility in arguing that reality itself is just a figment of imagination.
The McGurk Effect
The McGurk Effect is possibly my favourite perceptual illusion; it's just neat. Perceptual illusions are often used to discredit naive realism, but one of the reasons I tend to lead with the McGurk Effect in particular is that it can be used to demonstrate multiple distinct audio perceptions using a single audio sensation. Before I share with you a video where you can experience the effect itself, let me explain a little about what's going on. Audio perception does not simply occur through the translation of audio sensation. There are lots of ways in which human perception can be cross-modal, in that different sensations blend together to inform perception; colour can influence flavour. In the McGurk Effect, there is a single audio sensation being received. In the case of the video I'm about to direct you to, the audio sensation is "ba." I recommend that the first time you press play, listen to the entire video with your eyes shut. It's not even a minute long, and I've found people are more surprised by the effect if they experience it in this order. Then, repeat the video, only this time watch it as well. If you first listened to it you will recall that the only sound you perceived was a male voice continuously saying "ba ba, ba ba, ba ba," etc. Watching it this time, you will perceive the man attached to the voice first repeating "ba," but when the video changes you will now perceive first "da," then at the next change, "va." Toward the end the three video clips will be shown side by side, and depending upon which you look at you will perceive a different sound. The audio file hasn't changed. Go check it out.
I admit I'm a total nerd, but for many reasons the McGurk Effect both fascinates and excites me. The most relevant to this topic though is that it demonstrates at least one instance where what an individual is perceiving is demonstrably different to the raw sense data they are receiving. The sound waves travelling from your speakers to your ears haven't changed. The signal being sent from your ears to your brain hasn't changed. But your cognition does. You perceive things different to independent reality.
Some people will justifiably argue that perceptual illusions are extreme examples. I concede that. However, I disagree that they should be ignored because of this. Perceptual illusions demonstrate that it is invalid to insist that all human perception directly relates to the stimulus being received. It just doesn't. But, that doesn't mean that nothing is 'real' either. I find that the simplest, most practical explanation is that reality exists independently of an observer and that human perception is a useful abstraction of that reality. Which reminds me of the Fallacy of Misplaced Concreteness, but I'll bore you with that another time.