Otherwise "rational" people often believe weird things. But why weird? Obviously, you only notice that it's weird because you don't believe in them yourself. You find this bothering? Well, it is a little disconcerting isn't it, but it's basically because in some aspects of your life you like to use reason and in others you don't. It's expensive, in terms of brain-power, to think about so you'll more happily chew through life adjusting reality rather than your perception of it. More generally, it's a complete and utter failure to recognise that when you have a belief, it should be consequential to you, it should have an effect, it should produce an expectation of some kind of sensory experience. Without this, the belief is, at best, a moot one from the perspective of truth. Even if you did have some kind of circular definition of "real" being "can be experienced" because "can be experienced" means "real", I have to profess that I can cannot possibly think of better and more apt description of "reality" as we usually want to talk about it. I can illustrate it in a cute little dialogue:
Believer: "I believe in God."
Me: "Oh hai NPC, so glad you mentioned that. One quick thing: what do you mean?"
Believer: "I mean I believe in God, a higher power that watches over our lives."
Me: "No, actually, what do you really mean? Not really about what "God" is, I don't care, what do you mean by believe? Actually, scratch that one or we'll be here forever, I'll do the hard work for you: How does this belief affect you?"
Believer: "It means I live my life according to God because He laid out how to in the Bible. It's how I was raised and what I believe."
Me: "Okay. But how does this genuinely affect your life? What is it that you can feel?"
Believer: "I just feel it's right... you know?"
Me: "No, I don't really. That's a little wishy-washy for me. I'm sure that's fine, but, can't we not expect something more concrete? I'll try it another way: what are you expecting from this belief?"
Believer: "Expecting? I don't really expect anything from God. Christians sort of live for God, well, I'm not that much of a 'Christian' as such. You know I do the church thing on Christmas and Easter and so on. I don't really care about the theology stuff. So, I don't really expect anything."
Me: "Well, this is where your problem is, really..."
Believer: "Problem? How?"
Me: "Okay, I'll do the hard work for you can cut right to an example. Trust me, it'll be easier this way. You pray, right?"
Believer: "Yes. In church on the Christmases and Easters and stuff. At home occasionally, and you know those frustrating traffic jams where you cry 'oh God just let it...'"
Me: "Okay okay okay... I get the picture. But the more formal prayers. Actual hands-together-on-your-knees stuff where you reach out with all your heart - you know what I'm talking about, right? - and you actually do some praying. Not just this occasional exclamation because you're just used to saying 'Dear God!' out loud and it happens automatically. Actual prayer. You do that, right?"
Believer: "Yeah, sometimes. It's not a big thing, but..."
Me: "Okay. And who for? Yourself to get rich?"
Believer: "No! That's not what it's about, it's about wanting to help others. I'm not selfish or anything and that's what prayer should be about. People who pray for themselves are selfish, I don't think they quite get it."
Me: "How noble. So who is it you pray for?"
Believer: "Well, last time I prayed for my cousin's friend who was going in for complicated surgery. Why?"
Me: "Okay, so now we're getting somewhere. Do forgive me, I'm not saving you the hard work this time, we're actually visiting these middle-men. Did your cousin's friend make it through?"
Believer: "Erm... I think so. Can't remember too much detail, I just thought it'd be right to pray."
Me: "So your prayer caused your cousin's friend to recover? Obviously if your belief in God is sincere you should believe that."
Believer: "Well, kinda..."
Me: "I don't think there's a 'kinda' about it. Did you contribute to your cousin's friend's wellbeing?"
Believer: "If God heard me, then I suppose so."
Me: "Okay, so you're praying with no expectation that someone will get better as a result?"
Believer: "Well, maybe they do, maybe they don't. You can't prove it, can you? Maybe God hears, maybe He ignores it."
Me: "Wow, what a cunt... oh, sorry, I thought that if this all powerful being just ignored you that'd be a dick move. But you expect at least some answers, on average, right? If I asked for a thousand people to be prayed for and found another thousand that wouldn't be prayed for, and all other things being equal..."
Believer: "I see what you're doing here, you're trying to prove prayer with science."
Me: "No, I'm trying to prove it by observation."
Believer: "How is that different to science? You can't prove it with science."
Me: "It isn't, it just doesn't have that smarmy connotation of evil scientists trying to shit on your cherished beliefs along with it."
Believer: "You can't prove it with science, it's beyond science."
Me: "I'm not proving it with science, it's simple observation. If you're hit by a car traveling at speed you expect to be injured, right?"
Believer: "Of course."
Me: "Because you observe it to be so when it happens. It's the very same thing, it's only 'science' when you want a convenient excuse to ignore it because you simply have this trope in your head that says God is beyond science. Science is practically synonymous to observation, but at least calling it observation has a strength in the fact that you can't merely dismiss it for the sake of it being as such. Would you? Do you deny your observation that the sky is coloured blue?"
Believer: "Well, no, not at all. But science is..."
Me: "No more than observation."
Believer: "Fine fine it's just simple 'observation', whatever you call it."
Me: "So if you were to have a prayer you'd expect to observe a real effect right?"
Believer: "But you can't test it with sci..."
Me: "Observation. Please."
Believer: "Okay. Yes, you can't test it with observation. Or any of that stuff, it's just a belief."
Me: "If you like, but here's the big thing: If it works, you can observe it. Much as being hit by a car can be observed to cause injury. Now what effect do you suppose you can observe by being hit by an invisible car? Pardon my morbid and injury-related similes here - I find death and injury to be remarkably salient thought-experiments, it really gives you something you dread."
Believer: "Well... you'd still be hit by it, invisible just means you can't see it, says nothing about feeling it. And that's like God because you can't see God..."
Me: "Exactly! You've said exactly what I wanted you to. Well, unsurprising really as you are just a semi-straw man figment of my imagination for a thought experiment. So you can't see it, but you can sense it through an observed effect. Namely, being hit."
Believer: "I don't follow. What does this have to do with anything?"
Me: "It has everything to do with it. You simply haven't followed the logical consequences of the phrase 'I believe in God' properly."
Believer: "But I believe it, that's all that matters."
Me: "Well, you can keep telling yourself that, but unless you really think why you've thought that you probably don't believe it properly enough. You may as well just 'think' that you believe."
Believer: "But I really do believe."
Me: "If this was the case, would you agree that you could throw yourself off a building and be saved by the hand of God? It's what you'd believe, right?"
Believer: "No, that's not how it works."
Me: "Right, so God won't save you. And you say God won't actually respond to your prayer..."
Believer: "I did say God responds to prayer!"
Me: "You said that if you took a thousand people and prayed for them and a thousand people and didn't pray for them, you wouldn't detect a difference. You wouldn't observe one group doing better and the other group doing worse."
Believer: "Yes you would, because we know prayers are answered."
Me: "You see, here's the problem. When phrased that way, you seem quite happy to say that you can tell prayer works. I've outlined a set of observations and you agree that you'd expect them to be true if prayer worked. But phrased another way, you say quite sternly that prayer doesn't - only because you assume 'science' can't detect that prayer works, even though both situations are absolutely identical. There's a trope in your mind that just says 'science can't prove it' but you haven't examined what that actually means."
Believer: "Okay then, you can tell prayer works. Do the experiment."
Me: "Well, we did... it didn't exactly come out in your favour. It was properly controlled, everything that we would do in any other test was followed..."
Believer: "But prayer doesn't work like that."
Me: "Then how does it work? You say you expect to see an effect, but when we actually go looking for that effect you say it can't be seen. You have to pick one; it can either be an effect that can be detected or it can't."
Believer: "Okay then, it can't be detected."
Me: "You see, you simply thought 'I believe in God' because you thought you ought to. That was all. There's no shame in that, but you should at least try and think it through to what it means in the end. What you can expect to experience because of it."
Believer: "Okay, so I expect to feel God inside me. There, prove that with science!"
Me: "Okay, fine, that's okay. But how is what you've just said different from you just believing in God, but God not actually existing?"
Believer: "Because I feel God, God must..."
Me: "No, that's just circular. What experience would you expect? Remember, we're all just basically asking what experience you'd expect from God being a real thing. By real I mean something that can be experienced in a way that's different to either merely believing in it or it not existing."
Believer: "Real is something that can be experienced and something that can be experienced is real? Now who's using circular arguments?"
Me: "Care to proffer a better definition of what 'real' actually means? An invisible car that hits you and injures you is real, because you can experience it. An invisible car that doesn't injure you when it hits you, leaves no tire tracks as it breaks, produces no heat from its engine or squeal from its brakes or sound of its components crumpling as it hits you... that's real?"
Believer: "But it could be real and you can't prove that!"
Me: "If we consider an invisible car that doesn't injure you when it hits you, leaves no tire tracks as it breaks, produces no heat from its engine or squeal from its brakes or sound of its components crumpling as it hits you... then what use do we get from believing it's real? What about the invisible motorbike, or the invisible truck? Or train?"
Believer: "Well, obviously any of those could exist."
Me: "But what difference does it make? Do I look out for them despite knowing that no matter what I do and no matter what they do I won't ever be hit by one?"
Believer: "If you like."
Me: "Or I can just not consider them, in fact I didn't consider the invisible sledge - at least not until I mentioned it just there. None of them produce a measurable effect. If you're going to profess belief, you should ask what it means to believe it, and what you expect from it, not merely just take the mental short-cut. Simply ignore the 'believe in God' meme and ask what it actually means!"
Believer: "But obviously those things, like an invisible motorbike, don't exist."
Me: "Precisely. But how is this different to a God that also produces no measurable effect? You know, as you've just said God is!"
Believer: "Why do you atheists hate God and all the people who believe in him? For something you don't believe in you spend a lot of time thinking about it and talking about it. Why does it bother you so much?"
Me: "Because it genuinely pains me to see people try to change reality to match their mind than their mind to match reality."
- The believer pauses for a moment, trying to process the magnitude of the insult.
Believer: "So you're accusing me of not changing my mind, yes I can! I am completely open minded."
Me: "Well... it's more complicated than that, I'm accusing you of not recognising the barriers that prevent you from changing your mind."
Believer: "Like what?"
Me: "Okay, let's put it this way. What's your job? You know, brain surgeon, rocket scientist, CIA analyst..."
Believer: "Head of marketing strategy for a medium sized car wash firm."
Me: "Oh, how riveting... anyway, let me ask; in this job I presume you come up with a marketing strategy, you check it works by seeing if the company's profit goes up?"
Believer: "I suppose you could say that."
Me: "And you wouldn't deny that there's a way to check your strategy, right? You wouldn't say 'you can't prove my strategy works or doesn't work...'"
Believer: "Wait, I know where this is going - I'm not an idiot..."
Believer: "This has nothing to do with God. My job is completely different. I have to do my job, I just believe in God."
Me: "Right. But you need to address why it'd be somehow different. You happily take the phrase 'my new marketing strategy works' and then follow it through to generate the idea that 'my company will get more revenue'. And if you don't observe it, you know the strategy doesn't work. In a way, you've very much a scientist."
Believer: "Well, I wouldn't go that far..."
Me: "But in another case you outright refuse to make that jump between a belief or assertion and what it actually means"
Believer: "Because it's God!"
Me: "Let me finish. There has to be a reason you make the connection with one belief and not the other. 'Because it's God' isn't really a good enough excuse. 'God' here could be any god, or even invisible cars and motorbikes. So, if you let me waffle a bit more I can give you another analogy. After all, you said you were open minded."
Believer: "Okay, go on then."
Me: "Cheers. I myself am a structural engineer. I know this because, as it's my thought-experiment, I can be whatever I want. I basically have the skill and knowledge to address the structural integrity of any structure I see. I can tell you if a building is safe, or is about to collapse. I can even tell you if your bed is going to fall apart due to too much... erm, you know."
Believer: "Yes, I get you. I'm not a no-sex-before-marriage Christian, I know what you mean."
Me: "Admirable. Anyway, what about this chair? I can tell you if the chair is safe to sit on or whether it will collapse."
Believer: "Is this going to end up with 'actually I can tell you whether God exists in the same way I can tell you if a chair collapses'? Because I can tell you now that's really stupid. Even pig ignorant."
Me: "In a way, but not the way you think right now. The point is far more general and widely applicable than that. I can tell you before you sit on that chair whether it will collapse under you. Yet..."
Believer: "...yet you don't?"
Me: "Good. Exactly. I don't check it. Why?"
Believer: "Well... I suppose you don't check it because it would be a waste of time."
Me: "Not really, I'm discovering something about the world, and ensuring my own safety at the same time. I'd hardly call that a time wasting - time consuming, yes - but not time wasting. So why would you consider it a waste of time?"
Believer: "Because everyone knows chairs will support you weight. It'd be pointless to check."
Me: "And why...?"
Believer: "Because people just know, right? They've seen countless chairs and they can tell this one won't be different."
Me: "You know, for a figment of my imagination that insists on believing in God, despite not having evidence for it and being fully aware of that fact, you can be quite astute."
Believer: "Fewer back-handed comments would be nice."
Me: "Fine. Anyway, my point is that you don't check your chairs for structural integrity, and I don't check my chairs for structural integrity, despite having the ability to do so, precisely because we've both seen and sat on enough chairs to know that they don't, as a rule, fall apart. It's like a problem already solved. If I check a chair for its integrity, sit on it, then leave and come back I wouldn't want to check it again. It's a problem already solved; and while I wouldn't say it wastes time, it does consume an awful lot of it."
Believer: "Okay, so that's chairs."
Me: "Yes, and in your job you feel that you're a rational human being. You make the connection between belief and something to look for, and, when I've explained the chair analogy to you, you also make the connection between a belief and something to look for.
Believer: "But God is still different."
Me: "Not really, God is closer to sitting on a chair for you. It's an already solved problem, is it not? You've believed since you were young but never put any real thought into it, you attend church only for Easters, Christmases, weddings and funerals, you pray only when convenient or important... you're not a hardcore believer because if I told you about magic Mormon underwear or Catholic transubstantiation you'd say those beliefs were indistinguishable from insanity. Yet you insist on believing in God anyway, which next to the magic underwear is probably more far-fetched."
Believer: "Yes, but those are silly things, aren't they? God just is."
Me: "This is exactly my point; God just is to you. Because you've believed so long and the problem has been solved for you for so long, it just is. You probably came to religion from a young age, right?"
Believer: "I was just raised that way."
Me: "Exactly. You see you later developed powers of rational thinking, which is no different to becoming a structural engineer that can assess the integrity of a structure."
Believer: "I don't think you can get a college degree in rational thinking."
Me: "Much to the world's loss. But anyway, much like a structural engineer can assess if a chair will collapse under its weight, you've developed the skills, as a rational person, to make the connection between 'I believe in God' and what you expect to see if that's true. We've talked about this already."
Believer: "But no one can tell if God is real! That's the point."
Me: "Well, if that's so then why believe? It could be anything at all out there, if there's an 'out there' that makes sense. And even then, you'd still want to make a connection between what it is you believe and what it is that you expect to see from it. You do this at work, right?"
Me: "And you do it when you cross the road, right?"
Me: "You do this when you reject Mormon magic underwear. Right?"
Me: "You do this when you don't jump out of a building expecting Superman to save you... I hope."
Me: "But you don't do it with God. For you it's a problem already solved. You're like a structural engineer you can assess whether a chair will collapse, but simply flat-out refuses to do so - and when pushed even denies he has that ability. Even if given a building to assess, a bar stool to assess, a roofing structure to assess, just before or just after looking at a chair so we damn well know he can do it, he just plain and simply refuses to 'do' chairs. Just because."
Believer: "I still don't see how chairs are analogous to God."
Me: "You don't check the integrity of a chair, even if such a thing would be good for you, because you see it as a waste of time. You see it as a waste of time because it's an already solved problem. You solved the problem with one chair the very first time you sat on one as a child. That has been confirmed several times since. Then presume you go to university, get your degree in structural engineering and then you have the skills to do a better assessment of a chair's integrity before you sit on it. Yet it would never occur to you to ever check a chair precisely because it's a problem you solved as a child."
Believer: "And your point? Sitting on a chair proves it works."
Me: "A risky decision to take, perhaps. But I assume as a child your parents told you there was a God, you had Bible stories, nativity plays and so on... without the skills of rationality that you later developed and then happily employ every day this looks exactly the same as God being real. It's like sitting on a chair and finding out it works."
Believer: "It's a bad analogy, I think."
Me: "Because you're thinking an actual chair represents God, really an invisible chair that you can't check represents God."
Believer: "Exactly, you get it! I'm so proud."
Me: "But it's not rational."
Believer: "But God isn't rational thinking, it's belief."
Me: "And I've told you, there's no difference except that which exists in your own head. You believe a marketing strategy at work will gain you more profit, you test for that. But those are new problems to you, right?"
Believer: "Yes, almost every day is new and exciting..."
Me: "Well, sarcasm aside you'll find that you've never solved those problems too many times before. You still know to test your solutions - like, 'I have a new strategy, let's see if it gets me more profit', which is rational thinking. You might not think it is, but it is. With other problems in your life you simply refer back to already solved problems and don't think rationally about it."
Believer: "But what if I thought rationally about it, and then kept using that answer again and again?"
Me: "Well that would be human, which is good. As I said, it's time consuming to do this, so you're weighing up whether it's worthwhile. Is it worthwhile to check every chair you sit on, even ones that you sat on not five minutes ago?"
Believer: "Probably not."
Me: "You have an open mind, though. So would it make sense to deny that you could check the chair if you were able?"
Believer: "No, it wouldn't. But that's nothing to do with God."
Me: "It has everything to do with God! You simply backtrack to saying that there's no way to check if God is real, despite believing in him. You're moving God into a realm more akin to an invisible chair that exerts no force when you sit on it. You can't check its integrity before hand with skills as a structural engineer... yet you can't sit on it either."
Me: "There's no 'but' here. It's one or the other, you can either test the integrity of the chair to see if it'll collapse under you, or you can't sit on it. With God you're trying to have both! Precisely because it's such an old problem for you that you see it as a waste of time to use your rationality on it. You simply believe, but we saw before that if challenged on it you can't quite say what that belief entails properly."
Believer: "Yes, I simply believe, that's the point."
Me: "But why? You're simply believing because you've done it so long. If I presented this as a new thing to you, you'd come to the opposite conclusion. The car that's invisible and doesn't hurt you when it hits you and leaves no tire marks or smell from the engine or noise and heat from the brake pads, you admit that such a thing doesn't exist practically by definition."
Believer: "Because it doesn't."
Me: "But you can't establish why that's different to believing in God - except to say that you've always believed and because of this have no need or reason to actually use your open mind and assess it with your skills as a rational entity."
Believer: "Because I believe God does exist. It's beyond proof with science!"
Me: "But it's not beyond proof by expecting an experience from it. Otherwise God is an invisible chair you can't sit on. If you weren't already a believer, and were coming to this for the first time, you'd recognise this."
Believer: "No, I don't think you're right."
- The whooshing sound of a Time Vortex fills the hypothetical void, replaced by the slow slapping of sandals on the ground as Jesus appears.
Jesus: "Well greetings, friends."
Believer: "Sorry, who are you?"
Jesus: "I'm Jesus, son of Man, son of God. Nice to meet you."
Me: "Well fuck me, a talking Jesus."
Believer: "Oh, sorry Lord. Erm... you just look different to how I imagined. A bit... you know... a little..."
Jesus: "Darker? Yes. Does this surprise you? Or did you have that whole White-Jesus thing in your head?"
Believer: "Well... I suppose... I..."
Jesus: "Don't worry. It happens to everyone. You lack an image of me so you just create one based on what is near and convenient."
Me: "Well, that much tends to be true of people. But, over the last few years we certainly come to know what the middle-east looks like very well. We've seen Iraq, Iran and Palestine - that entire territory - on television because of the war on terror and the crisis in Israel. Arguably it's more widely disseminated and more salient than ever. We know that the native population of that area of the planet has darker skin - yet people who have the image of a white and western Jesus in their head won't adjust their internal idea of Jesus given this fact."
Jesus: "Unless you point it out to people and make them think about it."
Believer: "Wait... but you're Jesus, why are you siding with the atheist?"
Jesus: "Well, only for this bit. I mostly have a few objections I want to add in too. If one possesses the open mind required."
Me: "Fair enough, try it."
Jesus: "Do you doubt I could change your mind?"
Me: "My honest answer is 'I don't know', but I'd be intrigued to see if you can without altering any other parameters, such as merely convincing me that 'truth' or 'real' should be defined differently. After all, if I say something is just in your head isn't real, and then you convince me that something just in your head is real, we haven't really changed anything."
Believer: "See what I have to put up with?"
Jesus: "I'm going to start putting points on your Talking License. But yes, go on, I'll take your challenge and put forward a... let's call it a suitable extension to your ideas, without falling into the trap of just redefining 'true' for the sake of argument."
Me: "That's fair. What do you ask, O Bearded Great One?"
Jesus: "Your issue is the expectation of consequences, specifically sensory input. That is, what you can see, touch, smell, taste or feel."
Me: "Or the sense of balance, sense of hunger, and so on. There are dozens, not just five."
Jesus: "That was a good episode of QI, wasn't it? So you suggest that any one of those senses should be affected by the presence of something that is real."
Me: "Yes I do. The senses should be the deciding factor in reality."
Believer: "But isn't that obvious? We all sense..."
Jesus: "Talking license!"
Me: "Yes, expectation of some sort of sensory input determines what is consequential to us as it can meaningfully affect us."
Jesus: "Very well. But sensory input comes from outside your body. From what essentially amount to tools. Such as..."
Believer: "Oh, it's me... such as your nose, or your tongue, or ears... that right?"
Jesus: "Good, they're tools attached to your brain. They send electrochemical signals to your brain. Your brain then interprets them. No matter what the sense is, it doesn't become that sense until it hits your brain. Would someone who was numbed by paralysis from the waist down, isolated completely by the confines of a thought experiment, have a meaningful consequence - as we know it to be - from someone else pricking their foot with a pin? Lightly enough not to leave a mark."
Believer: "Oh! So they don't feel it in any way at all. If they don't feel it, it may as well not have happened. So... is it real or not?"
Jesus: "Indeed. Expectation of a sensory response doesn't arise from this. Providing the person doing the pricking with a pin is careful enough to hide so their actions cannot be seen or detected in any other way."
Me: "It's an interesting proposition. I won't fall into the obvious trap, which would be some form of relativism. That is, to say that the experience isn't 'real' to the paralyzed person, but is 'real' to the person holding the pin."
Jesus: "That's a shame, I was rather hoping you would fall into that one. So what is your answer? Sensory response is cut off, where does your definition of reality stand if you refuse to use relativism and create different 'realities' yet can't detect this event."
Me: "Then the answer is simple enough, the person holding the pin can reveal the knowledge to the paralysed person."
Jesus: "They're a deaf-mute."
Me: "They use sign language."
Jesus: "The paralysed person is blind."
Me: "They establish a code to indicate what they have done."
Jesus: "They're doing it mechanically from the far side of the planet with no other ability to communicate into the room with the paralysed person."
Me: "I think this counts as moving the goalposts, does it not?"
Jesus: "Perhaps, but assume my goalposts are already placed in a location where you can't reach them. I'm not moving them, you're simply missing them."
Me: "It sounds to me like these goal posts are not only outside the arena, but in a different galaxy, and even then not suited to the sport at hand. You're really violating the rules of a discussion with this. You're artificially limiting your thought-experiment to exclude any and all solutions to the problem you pose."
Jesus: "Perhaps, I just want you to elucidate a more general answer that doesn't, in fact, rely on merely practical objections."
Me: "A more general answer? Well, those suggestions I outlined earlier relied on information being transferred to that paralysed person's mind. We've already established that senses are just tools feeding into a brain. So there is no coherent difference between the senses directly attached to their body - their eyes, nose, ears... and so on - and someone just telling them."
Believer: "So you're implying that senses can be very indirect and that gets around it."
Me: "Not only that, but that everything sensory route is indirect, and that the idea of a 'direct' sensory route is merely an illusion."
Jesus: "An illusion caused by what?"
Me: "I assume it's caused by the fact we're working from the perspective of having a mind inside a body. We separate the world into what is and what isn't our body, for example, a severed arm isn't part of your body. At least not anymore."
Believer: "You really are morbid aren't you?"
Me: "And so that anything physically attached to our body must be the 'direct' sense. But as I said, this is just an illusion, it's categorising things in a way that only makes sense to us but not to the real world itself. And so they're all indirect senses, even if they are attached to our body."
Jesus: "Then consider this; if all sensory input is, to a degree, indirect, we cannot really tell, within our own mind from the inside, the difference between and input that is telling the truth and an input that is lying. The signal we receive is meaningless until it's processed by our consciousness."
Me: "As in if our ears were replaced by some other device that, instead of signaling to us sounds in the vicinity, played music that wasn't there or transported sounds from the other side of the planet?"
Jesus: "Yes, much like that."
Me: "Then I'd say that you can compare senses to determine what are consistent with each other, and which one was inconsistent. And so we can route out which one is lying. We don't cross a road through sight alone but with sound too to listen for buses that are coming. Similarly, if we infer the presence of someone from hearing their voice but can't see them, we have to consider alternatives such as them being genuinely invisible, just well hidden, or perhaps we're hearing their voice from a tape recorder. It's all about gathering sufficient evidence to match up our model with the real world. If our model doesn't match the real world, we need to know why."
Believer: "But what if all senses are lying?"
Me: "Hmmm... that would be the logical next step to consider. Most people seem to think that if all senses were lying to you would be able to assume no objective reality exists. That if everyone went around with lying senses that they would exist within their own reality. And so, we get this kinda New Age belief that reality is whatever we make it."
Jesus: "And can you really say otherwise?"
Me: "Well, I can try. I propose that if all senses are coherent and synchronized together, so that I couldn't identify which of the senses, if any of them, are lying then... it would simply mean nothing."
Believer: "What? But of course it means something. You're being lied to by your senses, that means the real would could be anything. That's far from meaningful."
Jesus: "Or to put it in far more technical terms; that's a cop-out."
Me: "Not so. I'm merely being consistent with my previous definition of reality. If all my sensory input was consistent and so no lie could be detected, then I do not expect a change of sensory input between those two systems. If I cannot detect the difference, the question is inconsequential and moot. Believing that my senses all tell the consistent truth or all tell consistent lies is no different to believing in a God that doesn't answer prayers in a statistically detectable fashion or doesn't miraculously save people when they fall from tall buildings. It's no different to caring about whether I can sit on an invisible chair that exerts no force. It's no different to crossing the road and looking out for invisible cars that don't hurt when they hit you. It's moot."
Jesus: "But can you do this without disproving an objective reality?"
Me: "Why yes, I can since you asked. If my senses lie to me and I cannot detect what the objective reality is like, that is not objective reality's problem; it's my own. My senses lie to me. My thought processes are lying to me. I can't tell, but that's inconsequential."
Believer: "Yeah, that is a total cop-out."