From dreams to the multiverse
Here’s a strange question — what is reality? Now it seems simple enough to say that “reality is what we experience” — “what we experience is real”. But is that true? I mean, who are “we” exactly — everyone? Are we not then implying that everyone experiences reality? What if two people experience different things? Is only one of them experiencing that which is real? If so — which one is really experiencing reality and which is experiencing an illusion? I mean wouldn’t both think they are both experiencing reality?
Most of us think we are experiencing reality itself. We trust out senses. But sometimes our senses fail us. Perhaps into seeing a mirage for example or into thinking a stick is crooked just because it seems bent when half of the stick is submerged underwater. So what do we do then? We use our other senses to verify the straightness of the stick by touching the stick with our hands. But what if all of our senses are simultaneously impaired — what then? How could we verify the accuracy of our sensory experience if we cannot escape our senses to verify them? Come to think of it…couldn’t all of our experiences be called into question now? How could we know?
This line of thinking wherein which all of our experiences and knowledge is called into question is called Philosophical skepticism or Radical skepticism. Proponents of such a view would argue that we can’t really know what is real and that we can’t really be rational in thinking that the experiences we have accurately represent reality. Now our experiences could be an accurate representation of reality, but we would not ever be able to ever know it and for this reason we can’t really trust our experience. So how are we to approach such a radical idea and what are we to believe if we are to remain rational?
1. A Survey
Let me begin by presenting some examples of scenarios which would seek to potentially call into our experience of the world around us. For each scenario I put forward I will address three things in turn. Firstly, I’ll address the subjective phenomenology — that is to say, the experience as it is perceived by the subject. Second, I’ll take a look at the objective ontology — that is, the objective state of affairs that is causing the experience by the subject. Thirdly, I address some scenarios which are similar to the one under discussion if any are relevant. With that, I will proceed with the first scenario — the dream argument.
Scenario 1: The Dream argument
Life is but a dream
Subjective Phenomenology of the Dream argument
It seems so silly to think that everything we experience could just be a dream, that we could be asleep and not even know it. But is this really so? What could we possibly argue to disprove such a claim? It seems that anything we could point to in an attempt to rescue our belief that we aren’t asleep could itself be just another thought in a sleeping brain. This point is made forcefully and vividly by the French philosopher and mathematician René Descartes. In his Meditations on first philosophy he makes one wonder if the difference between being awake and merely dreaming can even be distinguished at all.
Objective ontology of the Dream argument
At least I’m probably human
The dream argument holds that we are real persons, we exist, however, the experiences we have could all be illusory. The claim that we are dreaming, implies that we exist as physical entities of some sort at the very least. We must be physical entities that require rest which and which must be capable of dreaming. This does not exclusively leads us to believe that we are actually human beings (if such beings can even be said to exist in the supposed reality we know nothing of) but it is compatible with us being human, More than that, it is also probable that we are humans since we are likely to dream about things in our experience than things we know nothing or little of. However, if all is but a dream, then such a probabilistic claim does not make our existing as humans more probable since is merely the thought of a brain which knows nothing of reality.
Further reading: Meditations on First Philosophy by René Descartes
The Dream argument: A Similar scenario
The Butterfly Dream
An almost identical version of this was proposed years ago in an ancient Chinese writing called the Zhuangzi. In this writing Zhuang Zhou dreams he is a butterfly fluttering about. Then he awakes and finds out he is Zhuang Zhou. This feeling he has when he wakes — the thought that “ I was a butterfly, but now I see I am Zhuang Zhou” proves to him that when he was the butterfly (in his dream), he didn’t think he was Zhuang Zhou. His dream made it such that he sincerely believed something even though it was false. And what about now? Now he sincerely believes that he is Zhuang Zhou. But of course, this would also be a sincerely held false belief if he is dreaming. So what is he then?
When he woke to find himself as Zhuang Zhou we believed he was Zhuang Zhou. But at any moment he could also wake and find that he isn’t Zhuang Zhou, but indeed he is a butterfly. This shows that the fact that he can wake to regard his previous beliefs as false combined with the fact that he has no way to know if he’s sleeping calls into question the veridicality of his being awake now as well as the truth of the beliefs he currently holds.
Scenario 2: Brain in a vat
Subjective Phenomenology of the brain in a vat
A more exotic idea is that of the brain in a vat as introduced by the American philosopher Gilbert Harman. Suppose your brain is carefully removed from your body and placed inside of a vat filled with chemicals containing all of the necessary ingredients required for the survival of your brain. Further, let’s suppose the scientist responsible for the procedure had set up a series of electrodes connected to various neurons in your brain such that each electrode could send electrical impulses directly to your brain by way of a computer. These impulses could trigger certain senses, memories, and even your very thoughts themselves. We already know that certain parts of the brain are responsible for certain experiences we have, so if we could in principle know how to affect the brain with just the right stimuli as to cause a complete experience of the world, then we could create a completely false reality for the brain in the vat and they wouldn’t and couldn’t even know it. All of reality as you experience it could be a mere illusion and any time you think to yourself “this must be real” could itself be a thought that you were caused to have.
Objective ontology of the brain in a vat
At least I’m probably a conscious brain
On a view such as this, the only thing that exists of ourselves that we would expect to exist is our brain. At least in a Cartesian dream we might exist as a whole sleeping person, but to lack a body itself seems to take away more of what we believe to be, and yet we still wouldn’t even know it. We can try to rationalize our way out of it and attempt to convince ourselves that we aren’t a mere brain in a vat — but a real human person. However any such thoughts could be precisely what the mad scientist would cause us to believe. That is to say, our belief that we are a human person could be a belief caused by the mad scientist. When in reality, we are merely a single brain sitting in a jar.
Further reading: Thought by Gilbert Harman
Brain in a vat : Similar scenario
Multiverse theory and Boltzmann brains
In contemporary cosmology, the idea of a Boltzmann brain is discussed within multiverse theory, cosmological eschatology (which is concerned with the end of the universe), and when explaining the present state of thermodynamic disequilibrium in our universe. In multiverse theory for example, it can be proposed that the universe can potentially be a quantum fluctuation of the meta-stable quantum vacuum state. Fluctuations which entail the existence of a high number of particles arranged according to a given pattern to fluctuate from the vacuum would be more improbable than their small particle non-pattern based counterparts.
To put it in simpler terms, generally speaking multiverse theory is a theory about the origin of the observable universe — a universe which is composed of fundamental particles. One interpretation in multiverse theory holds that prior to our universe, there was something known as the quantum vacuum state — also just called the vacuum state. The vacuum state is a quantum state which is unstable. This means that in such a state eventually quantum fluctuations will occur. Quantum fluctuations are occasions where certain fundamental particles will randomly arrange themselves in certain ways. Some fluctuations are very small and simple. That is to say, they consist of a small number of particles arranged in a certain way.
By contrast, some quantum fluctuations are very large and complex. That is to say these fluctuations consist of a very large number of fundamental particles which are arranged in some particular way. Given this distinction it should be clear that larger fluctuations are more improbable than smaller ones — as more particles are arranged a certain way in larger fluctuations than in smaller fluctuations. These fluctuations can take on a variety of different forms because there is a variety of different arrangements the constituent fundamental particles can take. Any such form can be called a “universe”. One such fluctuation could be such that it only consists of an arrangement of particles that constitute a single rock for example — and in such a case we would have a universe that consists of nothing more than a single rock. By the same token another fluctuation could be such that it gives rise to an arrangement of particles which constitutes the entire observable universe as we experience it.
The next thing to notice is that if the quantum vacuum fluctuated a single rock into existence then that sole rock could and would be considered a universe. However, this universe wouldn’t be an “observable” universe because an observable universe would be one which includes at least one observer. Of course this assumes that rocks or fundamental particles are not sentient observing things but I’ll table this point for now to avoid an entirely different discussion about Leibnizian-monism or Panpsychism. Now we are brought to the question “why types of universe’s are observable universes?”. It would seem that a rough and ready answer would be that any universe which contains a conscious subject able to observe the universe they inhabit would be considered an observable universe.
It’s also very important to note that the entire observable universe we see around us isn’t necessary for the existence of conscious observers. The idea of a quantum fluctuation is that anything can fluctuate from the quantum vacuum — a chair, Mozart, a famous work of art, within the bounds of logical coherence — it doesn’t matter . All that is required is that whatever fluctuates from the vacuum is consistent with the laws of nature and of logic. Granted, something might not be able to remain existing very long if it’s existence is dependent one something else which does not exist, but this doesn’t change the fact that it can in principle come into being for some amount of time however short.
When discussing the origin of the universe in multiverse theory, we then have to ask which sort of fluctuation would be most probable in which there would exist an observable universe? I mean if we think about it, there could be a much smaller observable universe than the one we experience. Perhaps half the size, or the size of just our solar system for example. In fact, Roger Penrose (a mathematical physicist and philosopher of science of Oxford University) argues that the existence of a fluctuation the size of our solar system is vastly more probable than a fluctuation the size of the universe we see around us. He calls the numbers by comparison “utter chicken feed”.
In fact, the most probable fluctuation in which there is a thinking agent would be a fluctuation in which a single brain fluctuates out of the quantum vacuum. The reason for this is because it is far more probable that an eight pound brain form by chance by a random collection of particles that fluctuate out of the quantum vacuum than that there would be a much higher number of particles to arrange themselves in such a way as to form a whole universe or even a solar system. Simply put, a single brain is just far less complex than an entire universe.
Now one could contest that this brain is not a universe, so how does this even explain what it is in question. But here’s the rub; the brain does not actually need to even exist in an actual universe as we might know it but merely have the illusory experience of there existing such a universe. The agent (or, brain in this case) would not even know the difference. This brain would not even need to exist for a long period of time, so long as the memories, beliefs, and experience of the brain entail a long history of (albeit false) experiences. So essentially, this brain would have the same memories as you say — or anyone else on this Earth. This brain could have thoughts, beliefs, memories, and all experiences identical to those that you have. Sure these would all be illusory, because there is not universe external to the brain itself — but the subject (the brain) would never even know it.
Further, there would be no way for the subject to even find out that there is nothing existing externally. This is why such an idea is so very relevant. Because any one of us could be such a brain and we wouldn’t even know it. We may think that everything we experience is an accurate representation of reality, but we have to have of exiting out brains to confirm that something other out brain exists. Sure we can ask someone else, but those other people would also be illusory characters that don’t really exist — like persons in our dreams, just figments of our imagination. If we are really such a brain, then anything we may try to verify our experience against could just as well itself be an illusory extension of our mind when all that exists is a single brain.
This isn’t science fiction; this is talking contemporary physics and philosophy of science. Such an idea was first put forward by Austrian physicist Ludwig Boltzmann in his attempt to explain the thermodynamic disequilibrium state we find ourselves in and such brains have since been referred to as “Boltzmann brains”. There have been cosmogonies (models of the universe) proposed which try to make the existence of Boltzmann brains less probable, however many of them rely on utilizing a non-standard measure of probability. So for this reason, the idea of a Boltzmann brain is still very provocative.
Entropy and Boltzmann brains
That was the idea of a Boltzmann brain and its relevance in multiverse theory; however, originally this idea was used to explain the amount of entropy we see in our universe. In both cases, we have a strong illustration as to the similarities between the concept of a Boltzmann brain and the concept of a brain in a vat.
A Boltzmann brain as discussed in this writing is increasingly relevant when grasping the implications of cosmological eschatology. Cosmology studies the universe as a whole, from its origin (known as cosmogony), throughout its development, and towards its very end (known as eschatology). As the universe gets older and older, entropy (the amount of disorder of a system— roughly speaking) increases until our spacetime turns into a de Sitter space (which is vacuum dominated). At which time thermal fluctuations could occur within the vacuum. Of these fluctuations the most probable mass-energy observer that could fluctuate from a de Sitter vacuum would be a Boltzmann brain.
The Boltzmann brain is similar to the brain in a vat scenario in both its ontology, namely there existing only a brain, and in its phenomenological experience, since both scenarios endow the subject with the exact same illusory experience of reality. The experience a Boltzmann brain would be no different than the experience that we are familiar with, and there would be no way of knowing if we are indeed such a quantum fluctuation or not. It is for this reason I thought this would be worth sharing, especially for the more scientifically-minded who are interested.
Modern Similar scenarios
Simulation theory and Computationalism
More recently, theories have been put forward which rely more on our level of technological advancement and its relation to consciousness. I just want to briefly mention two such theories: Simulation theory and Computationalism. According to simulation theory, all of reality is at bottom a computer simulated reality of some sort. This includes the subjects within and all of their thoughts as well. Computationalism is very similar, in that it holds that all that is needed for conscious observers is computation. That is, the ability to think. Now, if the act of thinking itself can be emulated artificially then we would indeed have conscious beings which can be artificially created in an illusory world.
This survey — in sum, is a small outline of the topic of radical skepticism and a brief sketch as to the challenge this presents. The field in philosophy called epistemology deals with the study of knowledge and asks questions as to the nature of knowledge and how one can be said to acquire it (if at all). Another field in philosophy called metaphysics deals with questions that the physical sciences cannot necessarily answer on its own, although it has implications that call into question what we are as human beings and what reality is. The topic of radical skepticism seems to have much to say on both of these topics and a good understanding of these two sub-fields in philosophy will help one achieve a robust philosophical reflection on this issue.
3. Positive case in favor of our experience
What’s the worry?
Now there are those who land on either side of this intriguing topic because it questions what we are as humans as well as the nature of reality is. Perhaps we may not be able to have absolute certainty in some things since we’ve already seen how much our knowledge we think we have can be called into question. But can we at least craft a positive case for why we can embrace as true the reality that we experience? I think such a case can be made and here I will attempt to do just that.
We’ve seen that there are several different accounts that seem to call into our question our experience of reality. Sure we can’t prove that we aren’t in any of these scenarios, but does this give us a positive reason to believe any of these accounts are true? Surely merely listing different possible accounts of the nature reality does not by any means give one any reason to think that any of these alternative accounts are actually true. All of this really depends on the existence of any arguments put forward in favor of any the accounts laid out so far. But suppose we aren’t aware of any of these argument. Are we to think that the reality we experience is on an equal footing with these accounts?
If we are to hold to the truth of the reality we experience, it would seem prudent to have at least one positive reason to think that the reality we experience is indeed an accurate representation of reality. In addition, it would be ideal if we could provide some reason to think that any account that would call into question the truth of the world we experience is flawed somehow. I think both of these conditions can bet met.
Our Experience as a Properly basic belief
A positive reason to think of the world we experience accurately represents reality is found in the notion of properly basic beliefs. Most beliefs are themselves based on other beliefs. However, some beliefs we hold are beliefs that aren’t based on other beliefs. Philosophers call these kinds of beliefs “properly basic beliefs”. Such properly basic beliefs would be beliefs that we cannot prove, since they are not based on anything else, but nevertheless that we can be said to be rational in affirming. Some examples of such beliefs would be beliefs in the existence of objects in the external world, beliefs in certain metaphysical truths, or even some beliefs based on testimony. These beliefs might not be provable given the possibility of the illusion of experience, but we are rational in believing in them if we are to make sense of the world we do experience (so long as we don’t have any reason to believe such experience is illusory) even though these beliefs aren’t based on any other belief. It is true that there may be what are called “defeaters” which could call into question the truth of a properly basic belief one might hold. But in the absence of any defeater, that is to say — in the absence of any reason to think that a certain properly belief is not true then we are rational in holding that to the truth of such a belief on the basis of its proper basicality.
Properly basic beliefs and evidence
A very important thing to note is that a properly basic belief would be a belief one can rationally hold without any evidence. The proper basicality of a belief, that is to say, the foundational nature of a belief, serve as rational justification for one to hold that belief themselves. However, this does not serve to convince other of that same belief — this would be the role of argument and evidence. In order to convince someone else that a certain belief is true, one would usually refer to arguments and evidence. But if someone already holds a belief and holds it in a properly basic way, then arguments and evidence aren’t needed to convince oneself of the truth if that belief. Sure arguments and evidence would increase one’s confidence in truth if a belief they hold in a proper basic way — but arguments and evidence aren’t necessary if one already holds that belief in a proper basic way.
Properly basic beliefs as rational justification
This isn’t irrational either as we are not saying that one shouldn’t have some rational justification for their beliefs — because it seems one should if they are to remain rational. Instead, what we are doing is opening up the boundaries for what is considered to be valid rational justification. Not only are arguments and evidence acceptable as acceptable rational justification for a belief, but the proper basicality of a belief is as well for there are things that we are perfectly rational in believing even though we may have no arguments and evidence for that belief. Such beliefs aren’t necessarily irrational beliefs merely in virtue of our not being able to provide arguments and evidence for said beliefs. They could be deemed irrational if we didn’t have any rational justification for these beliefs, and this is where properly basic beliefs come into play.
If we can show that a belief is properly basic, then that can serve to provide rational justification for that belief even in spite of ones not having any arguments or evidence for that belief. Although it goes without saying that e belief that is backed with a sort of double warrant or justification is even more valuable since it would enjoy the justification of both its proper basicality as well as its support from argument and evidence. This certainly would change of trueness of a belief — since the idea of degrees of truth seems incoherent — but it would change the degree to which one can be said to be justified in holding a belief.
Properly basic beliefs: knowing vs showing
Another helpful distinction here would be the bifurcation between knowing a belief to be true and showing a belief to be true. Holding a properly basic belief is itself a way of knowing a belief to be true. That is to say, if a belief is properly basic is provides a rational justification for that belief such that one can know that belief to be true for themselves and be justified in holding that belief. However, this doesn’t serve to convince any independent party of the truth of this belief. That is to say, holding a properly basic belief does not provide a rational justification for that belief such that one can show that belief to be true to another party. A belief’s being properly basic serves as a justification for the person holding that belief, but for anyone who does not hold that belief. By contrast, argument and evidence can serve as a rational justification for a belief even to persons who do not hold a certain belief.
Properly basic beliefs without argument or evidence
Given the fact that the proper basicality of a belief serves as a rational justification for holding that belief (as does argument and evidence) then it would seem that one can remain perfectly rational in holding a belief even in the absence of having argument or evidence for that belief — so long as this belief is properly basic. A natural next question to ask would be what kinds of beliefs could be properly basic and without argument and evidence? One such example could be found in the notion of testimony. Suppose someone introduced themselves to you as “John” and you believe that their name is John even though you don’t have any independent argument or evidence to believe their name is John. Are you suddenly irrational in believing their name is John just because you don’t have any independent arguments or evidence that their name is John? Are you without rational justification for this belief?
Obviously not — for you can have rational justification for such a belief without argument and evidence, and this is found in the notion of a properly basic belief. Sure not all beliefs can be properly basic, but some can because some beliefs are not based on any other belief and this is what makes such a belief properly basic. In this case, so long as your belief that their name is John is not based on any other belief then this belief would be a properly basic belief. As such, you would be justified in holding this belief even in the absence of any argument and evidence and you would remain rational in so doing.
A point of clarification here is that one does not need to have certainty to be rational in holding a belief. It could very be the case that “John” isn’t “John’s” real name after all. This would not affect the fact that you would still be rational in believing his name was John given that (i) this is a properly basis belief and (ii) there was an absence of evidence to believe otherwise.
As we mentioned before, there could exist defeaters to a properly basic belief, which would nullify the justification for that belief. But in the absence of any such defeaters, one rational in holding to the truth of that belief on the basis that it’s proper basicality serves as a rational justification for the belief itself. In this case, unless you have any reason to belief that this person’s name is not John then you are still rational in holding to this belief unless and until you encounter any such defeaters.
Our experience as properly basic
In this discussion, we can also look at certain metaphysical beliefs that are properly basic. One such belief would be the belief that the external world exists — that radical skepticism is false. That is to say, that reality as we experience it accurately represents reality itself. Sure it seems possible that all that we experience could be an illusion — as per the examples laid out earlier. But what’s important to note is that the mere possibility that this could be illusory does not serve as a positive reason to think that it therefore is illusory. Now we have mere possibility on either side as to whether or not the reality we experience is an accurate representation of reality or not — but do we have any positive reason to think one way or the other?
The concept of properly basic beliefs shows that we do have positive reason to think that the world we experience accurately represents reality. That is to say, we can hold to the belief that the world we experience accurately represents reality in a properly basic way, and this belief will therefore serve as rational justification for one’s holding to this belief. Furthermore, in the absence of any defeater of this properly basic belief, then we are rational in holding to it. Any examples put forward which show that it’s possible that our experience is illusory do nothing to serve as a defeater of our properly basic belief in the validity of our experience because mere possibility is not a reason to think something is true but only that it is possible.
To be clear, if one had an argument which argued for the truth of our experience being an illusion then this would indeed serve as reason to think that our experience does not accurately represent reality. By contrast, merely stating possibilities would do nothing to provide any positive reason to believe one way or the other.
3. Positive Case against radical skepticism
For the sake of discussion I’ll use the term “UM” as an abbreviation for “unreliable mind”. This would refer to any such mind that could be a sample case in an argument for radical skepticism. A dreaming mind, a brain in a vat, and someone in the matrix would all be instances of what I will refer to as unreliable minds or “UMs”. I use the term “unreliable” because any such mind would be unreliable at producing beliefs which accurately represent reality. In fact, it is very notion that such minds are unreliable at producing realistic beliefs that make the thought experiments so provocative. The fact that UMs are unreliable at producing realistic beliefs seems to be an essential property of UMs.
Now the next natural question to ask would be, what are we to do if we are confronted with an argument for the truth of radical skepticism — for the truth of the claim that all that we experience is not an accurate representation of reality? It would seem to me that any such argument would be doomed to fail, for it would be self-defeating. The very idea that one is a “UM” would entail a logical contradiction. More specifically if one believes that they are a UM then they would have to believe these two logically contradictory contentions:
Contention #1: If I am an UM then it is not rational to believe that I am a UM.
Contention #2: If I am an UM then it is rational to believe that I am a UM.
Let’s look at each contention in turn.
This first contention argues that any successful argument that would argue that we are UMs would entail that we are not rational in believing that we are UMs. Here’s how this can be argued. Let’s consider what a UM would be. A UM would be a mind which is unreliable at producing beliefs which accurately represent reality. Given this, it would seem that is not rational to believe any belief produced by a UM since UMs produce beliefs which are unreliable at accurately representing reality. Now it could be argued that UMs don’t only produce beliefs which are unreliable at accurately representing reality. However, this does not provide a reason to believe that UMs produce beliefs which are reliable at accurately representing reality. All we know about UMs is that they are unreliable at producing beliefs which accurately represent reality. Let’s formalize this.
1A — A UM is a mind which is unreliable at producing beliefs which accurately represent reality.
1B — It is not rational to believe beliefs produced by a mind which is unreliable at producing beliefs which accurately represent reality.
1C — Therefore, it is not rational to believe beliefs produced by an UM.
Now, suppose we are confronted with a successful argument for radical skepticism. It would follow that we shouldn’t believe our own beliefs, since it isn’t rational to beliefs produce by a UM ( per premise c). Let’s formalize this:
2A — It is not rational to believe beliefs produced by a UM. (per 1C)
2B — I am a UM (conditional premise)
2C — Therefore, if I am a UM then it is not rational to believe a belief produced by my mind.
Now let’s suppose further that since we are conditionally holding the belief that we are a UM, that we also believe that we are a UM. Let’s make this premise f. It would follow that we aren’t rational in believing that we are a UM because this very belief that we are a UM is itself produce by an UM. Let’s formalize this:
3A — If I am a UM then it is not rational to believe a belief produced by my mind. (per 2C)
3B — The belief that “I believe I am a UM” is a belief formed by my own mind. (conditional premise)
3C — Therefore, if I am a UM then it is not rational to believe the belief that “I believe I am a UM”.
So here we have logically reached the conclusion that if we are an UM then it is not rational to believe the belief that we are indeed an UM. Thus Contention #1 is fulfilled.
Contention #1: If I am an UM then it is not rational to believe that I am an UM.
Contention #1 — Full argument outline:
1 — It is not rational to believe beliefs produced by an UM.
1A — AN UM is a mind which is unreliable at producing beliefs which accurately represent reality.
1B — It is not rational to believe beliefs produced by a mind which is unreliable at producing beliefs which accurately represent reality.
1C — Therefore, it is not rational to believe beliefs produced by an UM.
2 — If I am an UM then it is not rational to believe a belief produced by my mind.
2A — It is not rational to believe beliefs produced by an UM
2B — I am an UM (conditional premise)
2C — Therefore, if I am an UM then it is not rational to believe a belief produced by my mind.
3 — If I am an UM then it is not rational to believe the belief that “I believe I am an UM”.
3A — If I am an UM then it is not rational to believe a belief produced by my mind.
3B — The belief that “I believe I am an UM” is a belief formed by my own mind. (conditional premise)
3C — Therefore, if I am an UM then it is not rational to believe the belief that “I believe I am an UM”.
Contention #2: If I am an UM then it is rational to believe that I am an UM.
This contention is trivially true, for if one is indeed an UM then it is rational to believe this because it’s true after all. However, this contention contradicts contention #1, thus the very idea of one being an UM directly entails a logical contradiction. As such, I would hold that not only is it irrational to believe one is an UM but that it is impossible that one be a UM for this itself would entail a contradiction. For if I am an UM then I must affirm two propositions: (i) that it is not rational to believe that I am an UM (per contention #1) and (ii) that it is rational to believe that I am an UM (per contention #2) — and these are two self-contradictory statements.
· If I am an UM then…
o It is not rational to believe that I am an UM. (contention #1)
o It is rational to believe that I am an UM. (contention #2)
Thus one should not believe that they are an UM, since this would entail a logical contradiction.
In this writing we’ve reviewed the topic of radical skepticism by reflecting on the illusion on experience. We’ve surveyed different ways to understand why our experience can be called into question as well as reflected on the importance of this topic. Finally, we crafted a positive case to think that such a radical skepticism is unfounded and more importantly logically incoherent. Radical skepticism, although abstract, has real life implications and affects how we live and treat others because it questions our very experience if ourselves and reality itself. It is for this reason this question will always be one of great fascination and intense debate for years to come.
 The phrase ‘Prior to the universe’ is used colloquially here and is not used to endorse some hyper-time nor is it necessarily used to commit one to the idea that time existed before the origin of the universe as this would entail a contradiction depending on the definitions of the relevant terms.
 Panpsychism is a view which (broadly speaking) holds that the fundamental particles which constitute the universe are all conscious to some extent. It bears some similarities to a Leibnizian view of Monads which also are so small as to be indivisible yet conscious as well (depending on their hierarchical status laid out in his Monadology).
 Fun fact: The Penrose triangle (named after Roger Penrose; father) is an optical illusion — an impossible object which is featured throughout many works by M.C. Escher.