Friday, 22 January 2010

Perceptual Experiences

So today I sat through the exact same Epistemology lecture I sat through last year on Sense Datum Theories. Part of me felt like just leaving when I realised I'd heard it all before, but let's be honest here, doing it again isn't going to hurt. So in accepting being given this second chance to understand I will take to discussing it with you lot. 

Personally I feel like epistemology shouldn't have it's own class but should just be discussed in relation to everything else. But maybe that's just because I am not a fan - 

So I'll give you the two claims we are (apparently) committed to before I discuss. If you are a non philosopher and absolutely horrified by my sharing this with you I do apologise and hope it doesn't lead to you never returning. But at the same time I did warn you all of this probably happening and as I have been sat in the library for a couple of hours and found myself not really doing much of anything I may as well do this. Let's call it Education Through Procrastination. 

In fact, I quite like that. I will be keeping it, somehow. 

1) Typically, the direct objects of perceptual experience are external, mind independent objects
2) Typically, perceptual experiences are relations to their direct objects. 

'Right, so what does that all mean' I hear you ask! Well, I don't hear much other than the clicking and the tapping I'm causing myself nor could I adequately answer such a question (I'm assuming) but by-golly I plan to try (...something). 

Now, according to number 2 those perceptual experiences are relational just like my laptop is sat in front of me is relational. If I were sat somewhere else that whole 'in front of me' placement would not hold. So according to that, a perceptual experience needs to have a relation going on, if there is no one around to relate to then the experience can't be happening. 

Ok, so that makes sense enough. 

'But wait!' I hear you cry. Does it make sense if we think about illusory experiences or hallucinations? 
Well, if you are a Sense-Datum Theorist the answer would be to abandon claim 1 and keep hold of number 2. So there is still the 'relation to the object' thing going on, but it doesn't necessarily have to be some external object. Only thing, if it's not an external object, what the hell is it? If I can see the laptop, doesn't the laptop have to be there? 
Well, the Sense Datum guys would say that those perceptual experiences are mind dependent 'sense-data' that are actually these internal things inside our minds. 

This is the point I start going - wait, what!?

So (from what I've gathered at least,) our perceptual experiences, i.e. things I can see, touch etc. are relations to the 'sense-data'. 
This sounds like they are saying that those perceptual experiences I'm having are all in my head, which I can almost go for... almost. Yeah ok, so I'll agree that what we're perceiving isn't necessarily what's out there. It's not like we could ever know, my experiences are all subjective. So on a low low scale, maybe when I see blue you can see green - that's not to say we're going to sit and argue about the blue object we're both looking it, but rather we see different things that are called the same thing through that relational language stuff. I learn to call this thing I see blue and so do you, even though we don't see the same thing. 
Sure, fine. This is ok. But now we're getting more into the 'what?' 

So how is it that you and I can both see a table if this is all some internal mental sense data relation? There has to be something making me perceive a table, right? 

Well I think so. But then you have those idealists that just make my head hurt who I think say no. Now, maybe I'm just misinterpreting the whole thing, but I think the idealists would say that everything I perceive and experience is just some representation or illusion or something and not what's really there. But then you have to wonder what really is there... 

It almost feels like they either don't have an answer or they're just going to make stuff up and hope it flies. 

I'm not really sure about all this idealism - It makes my head hurt. 

But please, enter into discussion (especially any philosophers!) and let's work all this out together! 


  1. I’m just an amateur, and I also don’t much like epistemology – I’d rather just do ontology and then worry about how much of it I can save from the sceptics later – but I’ll have a go, and you can let me know if any of it makes sense.

    1) Typically, the direct objects of perceptual experience are external, mind independent objects
    2) Typically, perceptual experiences are relations to their direct objects.

    The first one sounds like direct realism to me. I suppose 2 would be part of direct realism also, as the material objects have a causal relation to me as I perceive them. Sense datum theories get rid of the first one and keep the second for the reasons you mentioned. In the case of hallucination direct realism would have to fall back on a sense datum type theory anyway to account for a perceptual experience without an object.

    So sense datum theories have the edge in hallucination but there is something kind of spooky about them. Say you are looking at your laptop, and the screen slowly fades to black before your eyes, is that one sense data slowly changing or a rapid series of very slightly different sense data? They are also very Cartesian, in that they are objects of the mind from which we infer the existence of physical objects. But if we reject dualism, and accept some form of physicalism, the objects of the mind are physical objects! So then it appears that a specific type of physical object (a brain state) has the properties that were supposed to be mind dependent sense data standing in for physical objects.

    Idealism gets a raw deal in my opinion, but I understand why, because it’s a little bit nuts. It just keeps the sense data and gets rid of the objects. Which does kinda make sense. If I have the sense data of a red ball and I take away the redness and the ballness there is nothing left to take away; objects just are the sense data. It’s simpler than the sense datum theory, but it still needs to account for the regularity of ordinary perception. Berkley did it by having God as the constant perceiver of everything:

    There was a young man who said "God
    Must find it exceedingly odd
    To think that the tree
    Should continue to be
    When there's no one about in the quad."

    "Dear Sir: Your astonishment's odd;
    I am always about in the quad.
    And that's why the tree
    Will continue to be
    Since observed by, Yours faithfully, God."

    Others did it by positing “permanent possibilities of experience” in place of material objects, which deals out quite a heavy blow to the apparent advantage of simplicity the theory had over sense datum accounts. Also, idealism just flips around the hallucination problem that made direct realism difficult in the first place because it now seems hard to differentiate hallucination from ordinary perception. A hallucination of a red ball is just the same as a red ball in idealism, but it does seem genuinely possible to hallucinate, and we need a theory of perception that can handle the distinction, even if only with some difficulty, like direct realism.

    Well, that’s about all I can manage at 3am. I am sure you were already familiar with the vast majority of what I have written but it has been helpful for me to write it… I think… I hope. Maybe some of this stuff will stick in my head now, and hopefully some small bit of it can be of some small use to you.

  2. "So how is it that you and I can both see a table if this is all some internal mental sense data relation? There has to be something making me perceive a table, right? "

    Why not say, the Table doesn't exist in reality? You and me would look at an object and surmise that it is a table, but without our preconcieved labels that we regularly unconsciously and consciously surplant onto the sensory information we're experiencing, how can you say then, what you are calling the, 'table' isn't actually just apart of the floor/wall? What actually makes it separate apart from ourselves?

    If we looked at a battlefield and saw the field covered in bodies, blood and guts, we would describe it as a battlefield covered in blood and guts, and would probably cry (I would anyway..). But if an alien came down and looked at the field, he would see it all as a whole, and wouldn't have the preconcieved notions to see each part as separate from the whole, or might even view some parts as whole and some as separate based on his own preconcieved notions that he may have.

    Further reference would be how when the Conquistadors were first revealed to the Aztec's, many Aztec's thought the Spaniads' on the Horses were one whole animal. That it wasn't a man on a horse, it was a thing with two arms, a head and four legs with an extra head directly in front. The Aztecs also hadn't invented the wheel but had invented highly advanced forms of farming through the seasons. Now I hear YOU say, how can you achieve so much, build great buildings do all these things, and not discover the wheel? It makes ME wonder, what else are we missing, that perhaps another intelligent species would say the knowledge was staring straight at us?

    My second argument would be, how can you be sure that the other person agreeing with you, that it is indeed a table, isn't actually just an illusion also created by your mind? You can't be sure.

    :P But seriously, if your mind has thought up ME, you're really sick Penny. You need help :P hehehe

  3. I simply have to weigh in shouting "empirical research!", especially now smoking's been mentioned. There's been a load of research on decision making in recent years - Dan Ariely's 'Predictably Irrational', for example, is an absolute hoot and terrifying at the same time. We're discovering more and more that humans are really terribly simple creatures, often just choosing the option that seems least scary and convincing ourselves (see cognitive dissonance) that we've done what we really did want to do, and often ignoring consequences simply because we can't understand them, so banish them from thought. Tim Bell was fascinating on The Bottom Line recently (business again preempting science) describing his anti-smoking advertising from years ago. Health based ones are usually ineffective "because young people don't die" (we can't square the effects with ourselves), but if you heighten the dissonance, proving to people that they really don't want to do what they're doing, they stop because they can't cope with the psychological pain. He focused on bad breath. It's posited that massive credit card debt often has a similar cause: people literally can't conjure in mind the image of themselves a few years later, because they've no idea of what it's like to be that person. So very many moral choices are similar. We know well that it's only with video footage that disasters in the world change in our minds from a set of numbers into human suffering (hence Gordon Brown's idea that the internet is a human right - it lets us see the whole world as human). The choice to give money and save lives remains the same, but now we can visualise the suffering, we feel like we're donating to stop a very different thing. The theme I'm carrying, of course, is that we don't do the right thing because we can't really grasp in our heads what that thing would be like if it were true. I can't be alone in finding the following in my political views: group g is unlovable to me because they've been changed by circumstance c, but I know that c was completely out of their control, yet I STILL dislike them and become rather right wing, even though I know this is wrong (rationally speaking; I'm ignoring the politics). Then I go and read lots about c, their situation becomes more real to me, and I go all lefty. Happens every time, just like in citizens' juries. Step up further into the real world: I don't give money to beggars. Why, really? It's because if I gave money to one I'd have to start giving money to lots of them, and while I can absolutely afford this and I think it's a good thing, the discomfort and unhappy complexity of having to keep bringing others' suffering into my mind as I wonder "how hungry does he look?" several times a day is rather scary. I'm sure I'll continue thus, though I know it's wrong, until there's enough dissonance to push me away. Why not change now? I answer by returning to the research. Humans HATE having to make decisions, to an extent far greater than the normal saying would mean. We are miles away from our self-image here. The whole point of the dissonance model is that if we can find a way of being happy with what we're doing, our brains make us believe we want ourselves to be like this, and we stop fussing. Think of what we have to do to change: we have to do the same as the advert, heightening the dissonance, making it so screamingly obvious in our minds that we don't want to do what we're doing that we have to change our behaviour just to stop the distress. Weakness of will is the default state, and it's a rare, difficult, and very human capacity to manage to overcome it from time to time.