# Criteria for Reality > ###### Problem > [Chapter 3](3%20-%20Problem%20Solving.md) argued that we acquire ever more knowledge of reality by [solving](Problem%20Solving%20Process.md) [problems](Problem.md) and finding better [Explanations](Explanations.md). But when all is said and done, problems and explanations are located within the human mind, which [reasons](Reason.md) via a fallible brain, and takes in information via fallible senses. So what entitles a human mind to draw conclusions about objective, external reality from its own purely subjective experience and reason? To answer this question, we will: * Argue for [Realism](Realism.md): that external reality does objectively exist * Explain how we can learn about external reality via the [Problem Solving Process](Problem%20Solving%20Process.md) * Have a brief interlude where we explain that there is no [Hierarchy of Theories](Hierarchy%20of%20Theories.md) * Introduce a [Criterion for Reality](Criterion%20for%20Reality.md) that will allow us to classify entities as real * Explain how all of this relies on the profound nature of the [Self Similarity](Self-Similarity.md) of reality ## Argue for Realism A good way to understand the true relationship between reason and reality is via [Defending Science by Arguing Against Solipsism](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md). If we [take solipsism seriously](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md#Taking%20Solipsism%20Seriously) we see that it self destructs. It either leads to [Contradictions](Contradiction.md) and undermines it's own foundational claims, or if one tries to slip out of the contradictions we find that it is simply [Realism](Realism.md) in disguise, weighed down by unnecessary assumptions. So we can continue, reassured, with common-sense [Realism](Realism.md) - objective, external reality does indeed exist. ## External Reality can be learned about via Problem Solving We must now show that external reality can indeed be learned about via the [Problem Solving Process](Problem%20Solving%20Process.md). This point of view was first held by Galileo, and it is [what caused the Inquisition to exile him](Galileo%20vs%20the%20Inquisition.md). The Inquisition's position was: No amount of observation or argument can ever *prove* that one explanation of a physical phenomenon is true and another false. So how can we claim that our theories have any bearing on external reality? Now even though the Inquisition were [realists](Realism.md), their aforementioned position has the following in common with [Solipsism](Solipsism.md): they both draw [Arbitrary Boundaries Beyond Which Human Reason Cannot Access](Arbitrary%20Boundaries%20Beyond%20Which%20Human%20Reason%20Cannot%20Access.md). Their main objection is that [Scientific Problem Solving](Science%20is%20Problem%20Solving.md) does not [deduce](Deduction.md) its conclusions from any ultimate source of [Justification](Justification.md). Without this external reality will always lie beyond a boundary that is inaccessible to [Problem Solving](Problem%20Solving%20Process.md) (but not The Bible, of course). Our argument against this position can be found by [taking the following theories seriously on their own terms](Take%20Theories%20Seriously%20on%20Their%20Own%20Terms.md): 1. [Argue Against The Inquisitions Theory: Taking it Seriously leads to contradictions](Galileo%20vs%20the%20Inquisition.md#Taking%20The%20Inquisitions%20Theory%20seriously%20on%20it's%20own%20terms) 2. [Argue Against Solipsism: Taking it Seriously leads to contradictions and indefensible explanations](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md#Argue%20Against%20Solipsism%20Take%20it%20Seriously) 3. [Argue Against Earth is Enclosed in a Giant Planetarium: Taking it Seriously leads to contradictions and indefensible explanations](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md#Argue%20Against%20Earth%20is%20Enclosed%20in%20a%20Giant%20Planetarium) What do these three theories have in common? They all grant that [Scientific Problem Solving](Science%20is%20Problem%20Solving.md) works within some arbitrary boundary, but not outside of it. And, if taken seriously, each theory can be shown to be a convoluted version of a simpler theory. Each theory is indefensible. Arguing for [Arbitrary Boundaries Beyond Which Human Reason Cannot Access](Arbitrary%20Boundaries%20Beyond%20Which%20Human%20Reason%20Cannot%20Access.md) is indefensible. The key insight is that by positing that we cannot learn about external reality, that is *just another arbitrary boundary*. We would be claiming that [Problem Solving](Problem%20Solving%20Process.md) somehow breaks down when applied to the nature of reality itself. But we have already shown how arbitrary boundaries are indefensible! So external reality does exist and we can learn about it via problem solving. Not in some absolute [Justified](Justification.md) sense, but in the sense that given a problem, and two competing theories, we can still have one theory that is preferable to another in solving our problem. Thus, by iteratively finding better solutions to problems, we gain knowledge, as articulated in [Poppers Theory of Knowledge](Poppers%20Theory%20of%20Knowledge.md). ### Interlude: There is no Hierarchy of Theories But in light of this conclusion, what can we say about the arguments that made solipsism and its relatives superficially plausible, namely that they could neither be proved false nor ruled out by experiment? What is the status of those arguments now? *If we have neither proved solipsism false nor ruled it out by experiment, what have we done*? There is an assumption built into this question: namely that there is a [Hierarchy of Theories](Hierarchy%20of%20Theories.md). But there is no hierarchy. Explanations are not justified by the means by which they were derived; [they are justified by their superior ability, relative to rival explanations, to solve the problems they address](Explanations%20Are%20Justified%20By%20Their%20Superior%20Ability%20to%20Solve%20Problems%20They%20Address.md). That is why the argument that a theory is indefensible can be so compelling. A prediction, or any assertion, that cannot be defended might still be true, but an explanation that cannot be defended is not an explanation. The rejection of ‘mere’ explanations on the grounds that they are not justified by any ultimate explanation inevitably propels one into futile searches for an ultimate source of justification. There is no such source. Nor is there that [hierarchy](Hierarchy%20of%20Theories.md) of reliability from mathematical to scientific to philosophical arguments. Some philosophical arguments, including the [argument against solipsism and arbitrary boundaries](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md), are far more compelling than any scientific argument. Indeed, every scientific argument assumes the falsity not only of solipsism, but also of other philosophical theories including any number of variants of solipsism that might contradict specific parts of the scientific argument. ## Criteria for Reality At this point arguments against [Realism](Realism.md) have been absolutely obliterated. We can move forward embracing it: there is indeed an objective external reality that exists and we can learn about it via problem solving. But now we continually have to ask and answer the question: what entities that are referred to in competing explanations really exist in that external reality? Why is it that [Newtons Force of Gravity Is Not Real, But Einsteins Curvature of Spacetime Is Real](Newtons%20Force%20of%20Gravity%20Is%20Not%20Real,%20But%20Einsteins%20Curvature%20of%20Spacetime%20Is%20Real.md)? We need more than just a rejection of [Arbitrary Boundaries](Arbitrary%20Boundaries%20Beyond%20Which%20Human%20Reason%20Cannot%20Access.md). For example, rejecting solipsism merely allowed us to embrace realism, not determine which entities *are actually* real. Deciding an entity is not real is equivalent to rejecting the corresponding [Explanation](Explanations.md). To decide if an entity is real, we need to develop reasons for accepting or rejecting the existence of entities that may appear in contending theories; in other words, we need a [Criterion for Reality](Criterion%20for%20Reality.md). The criterion that we will use is [Dr Johnsons Criteria](Dr%20Johnsons%20Criteria.md). It has several different flavors, each of which is interesting in its own right: >###### Dr Johnsons Criteria > 1. If something can kick back, it exists. > 2. If an entity is [Complex](Complexity.md) and [Autonomous](Autonomous.md) according to our simplest explanation, then that entity is real. > 3. If a substantial amount of [Computation](Computation.md) would be required to give us the illusion that a certain entity is real, then that entity is real. Where by "kicking back" we just mean that it requires independent explanation. ## Self Similarity of Reality We started this chapter by admitting that problems and explanations are located within the human mind, which reasons via a fallible brain, and takes in information via fallible senses. But [Galileos Discovery](Galileos%20Discovery.md) of our relationship with external reality leads to a profound realization: the reliability of scientific reasoning is not just an attribute of *us*, of our *knowledge* and our *relationship* with reality. It is also a new fact about *physical reality itself*. Reality is *science friendly*. It provides evidence to anyone who is looking the right way. There is no need for authorization or holy texts. Galileo may have thought this self-evident, but it is not. It is a substantive assertion about what physical reality is like. Logically, reality need not have had this science-friendly property, but it does — and in abundance. Thus physical reality is [Self-Similar](Self-Similarity.md) on several levels: among the stupendous complexities of the universe and multiverse, some patterns are nevertheless endlessly repeated. Earth and Jupiter are in many ways dramatically dissimilar planets, but they both move in ellipses, and they are made of the same set of a hundred or so chemical elements. It is this [Self-Similarity that Provides Accessibility to Knowledge](Galileos%20Discovery.md#Self-Similarity%20Provides%20Accessibility%20to%20Knowledge). There are laws and explanations, reductive and emergent. There are descriptions and explanations of the Big Bang and of subnuclear particles and processes; there are mathematical abstractions; fiction; art; morality; shadow photons; parallel universes. To the extent that these symbols, images and theories are true — that is, they resemble in appropriate respects the concrete or abstract things they refer to — their existence gives reality a new sort of self-similarity, the self-similarity we call [Knowledge](Knowledge.md). ## Big Ideas This chapter is philosophically quite deep, so it is worth summarizing some of the main themes and thinking tools used in it's arguments: * Explanations should follow [Occam's Razor](Occam's%20Razor.md) * [Be on the lookout for *Arbitrariness*. It may just be the weak link in an argument.](Arbitrary%20Boundaries%20Beyond%20Which%20Human%20Reason%20Cannot%20Access.md) * But remember, you can often only identify an [arbitrary boundary](Defend%20Science%20by%20Arguing%20Against%20Arbitrary%20Boundaries.md#What%20makes%20a%20boundary%20arbitrary?) by [taking it seriously](Take%20Theories%20Seriously%20on%20Their%20Own%20Terms.md) * [Take Theories Seriously on Their Own Terms. Some may just self destruct.](Take%20Theories%20Seriously%20on%20Their%20Own%20Terms.md) * [If a Theory Can Explain Anything, It Explains Nothing](If%20a%20Theory%20Can%20Explain%20Anything,%20It%20Explains%20Nothing.md) * [Contradictions](Contradiction.md), [Incompatibility](Incompatible.md), [Inconsistency](Inconsistent.md) are all forms of [Bad Reasoning](Bad%20Reasoning.md) and argument. We should seek to use [Good Reasoning](Good%20Reasoning.md). * When there are two [Incompatible](Incompatible.md) ideas, you are [Forced To Take a Position](Forced%20To%20Take%20a%20Position.md) * [Explanations Are Justified By Their Superior Ability to Solve Problems They Address](Explanations%20Are%20Justified%20By%20Their%20Superior%20Ability%20to%20Solve%20Problems%20They%20Address.md). We can rule out theories by showing that they are *bad explanations* * [Newtons Force of Gravity Is Not Real, But Einsteins Curvature of Spacetime Is Real](Newtons%20Force%20of%20Gravity%20Is%20Not%20Real,%20But%20Einsteins%20Curvature%20of%20Spacetime%20Is%20Real.md) --- Date: 20241201 Links to: Tags: References: * []()