Your Ability to Imagine a Scenario Does Not Make It “Theoretically Possible”

Stuart K. Hayashi

Introduction
In my home state of Hawai‘i, superstitions abound. Every New Year’s Eve, one does not merely practice certain rituals but also eats certain foods. I have been assured that this will please the spirits and they will reward us with luck throughout the year. When I ask different people if they truly believe all this, they usually give the same reply. They shrug, laugh sheepishly, and say, “Well, ya never know. It’s possible there might be something to all this.” People believe this might possibly be true simply because they can imagine it.

This notion that if you can imagine a scenario, that proves that it is possible, is very common. It serves as the major excuse for belief in the supernatural, such as fortunetelling, ghosts, demons, and deities. It is also a rationalization that underpins so much pretentiousness in philosophy.

This is may be familiar to you. It has become routine that, after taking Philosophy 101 class, someone will say, “Gee, maybe my whole life is not real. Maybe all of my experiences are an illusion, and I am actually a brain in a jar imagining my life. This is theoretically possible.”

Such talk was popular long before the release of The Matrix. It has an extensive history of being entertained copiously in formal philosophy, in some form or another. Immanuel Kant had a version of it, and it is famously associated with Plato. The idea was also extolled by the ancient Chinese philosopher Zhuang Zi. He said that one day he dreamed he was a butterfly, but maybe he is actually a butterfly dreaming that it is Zhuang Zi. Buying into the assertion that what we interpret as sensory evidence might all be misleading, the philosopher Karl Popper proclaimed seriously, “...we never know what we are talking about.” (To that I reply, “Speak for yourself, buddy!”) And although Rene Descartes ultimately did not affirm his agreement with this idea, he still presumed it deserving of very serious consideration.

Disturbingly, the Enlightenment Era philosopher David Hume was explicit in saying that his ability to imagine a scenario was sufficient grounds for deeming it a theoretic possibility that deserves your study. This starkly contradicts Hume’s reputation among today’s professors — that he was a strict empiricist all about sensory experience. As worded by Hume, “To form a clear idea of any thing [that is, to imagine something vividly] is an undeniable argument for its possibility and is alone refutation of any pretended demonstration against it.”

We will return to this erroneous supposition of Hume’s a bit later in this essay. Although Hume made some very sound arguments for free-market economics and having a laissez-faire and constitutional liberal republican Night Watchman State, much of his influence in the area of epistemology, such as with what he has said above, has contributed to setting much of Western society on the wrong track.

People who indulge in this talk — that being able to imagine something is proof that it is possible — have no actual basis for doing so.

I already knew that years ago, and I would offer them this same reply.

I can imagine an isolated ice cube falling to the bottom of a glass of water and remaining on the bottom for eternity. My ability to imagine this is still no basis for introducing this scenario as a theoretic possibility. For a proposition to be worth some consideration as a theoretic possibility, there must be evidence to support it.

And, as far as I was concerned, that was that. However, on Thursday, July 27, 2023, I came up with some additional points about this. These additional points, I think, make more use of formal logic. My new manner of phrasing the matter goes farther down to the foundation of metaphysics and epistemology. The main purpose of the essay you are reading is for me to present my argument in this new form. But, first, I must give some background information that serves as the basis for my new argument.

 

 
The Context Behind the Issue
This idea that your sensory experiences might be distorted or illusory, and that there might be a truer plane of existence with which you have not yet made contact, is called metaphysical Idealism. This is not to be mixed up with moral Idealism, which is a persisting commitment to ethical principles. And the ramifications of metaphysical Idealism are not confined to metaphysics. In the realm of epistemology — the discipline that studies how do we know what we know — metaphysical Idealism is frequently accompanied by epistemic Rationalism, which should not be confused with rationality.

This epistemic Rationalism is the notion that there are valid and true ideas we hold that are innate, à priori, and which are truer than knowledge that we can induce à posteriori, meaning from from sensory experience. Someone can be a Rationalist without agreeing that it is theoretically possible that all sensory experience is suspect or misleading or illusory. Still, being an epistemic Rationalist is a very convenient position for someone who agrees that all sensory experience is illusory.

For a metaphysical Idealist, epistemic Rationalism is supposed to answer the question, “If everything learned from sensory evidence is subject to doubt, how do you know that all of that sensory evidence is thrown into doubt?” Once again, people say that their ability to imagine that waking experience is an illusion is enough to make it a theoretic possibility. Those who are most adamant in metaphysical Idealism and epistemic Rationalism go farther, saying they know all this conjecture is a legitimate evaluation.

There is a name for this idea that your consciousness can recognize truths — truths about entities that exist outside of your  own consciousness — independently of investigation of those entities by means of sensory experience. That is, the idea is that even if no one ever investigated the matter by means of sensory experience, you can still know what is true about the entities existing outside of your own consciousness, entities such as trees and flowers and volcanoes and clouds and galaxies and other humans.

The name also applies to a still-more-radical idea. The more-radical idea is that, independent of going through sensory motions to affect the entities outside of your own consciousness, your consciousness alone can will those entities outside of your consciousness to change their nature and behavior. The name that the writer Ayn Rand gave those ideas is “the Primacy of Consciousness.”

It is true that your own consciousness can sometimes influence the entities outside of it. But your consciousness can do this only by means of going through motions with the realm of sensory experience, not merely thinking with your consciousness but acting in reality, through physical motions, to implement the ideas from your consciousness.

For example, the Wright brothers conceived of — imagined — heavier-than-air flying machines when none had existed. Then, through their efforts, they created airplanes in reality. In this respect, what once manifested only in their imaginations had also become real entities that existed independently of their consciousness.

But they did this through sensory experience. They observed that, as birds flew, the birds changed the direction of their flight by changing the direction of their wings and the angles at which edges of their wings had bent. The brothers then employed their bodies to draw up plans and diagrams that they formulated to accommodate such observations. They built models and prototypes of a flyer, and they employed their senses to observe the results of tests they ran on such prototypes. By contrast, for the Wright brothers to employ a Primacy-of-Consciousness mindset would have been for them merely to attempt to wish or pray airplanes into being. After all, their father was a priest. 

Likewise, here is another example of the Primacy of Consciousness. Suppose that on Monday, I pray that Hawai‘i will not be hit with an earthquake on Tuesday. Then, on Tuesday, Hawaii experiences no earthquake. Then I chalk up the absence of such a disaster to my having prayed to God. I still performed a physical action — I put my hands together and spoke with my mouth. But there is no evidence that this had any causal effect on seismic activity. Moreover, because God supposedly can read my mind, it probably would have been just as effectual if only in my head did I ask God that there to be no earthquake. Hence, this is the Primacy of Consciousness at play.

It is also the Primacy of Consciousness when my loved ones eat a particular dish on New Year’s Eve to bring good luck. Here, good luck refers to steady finances and the good fortune of a hurricane not hitting Hawai‘i months later. Again, this ritual does involve a physical action with entities outside of people’s consciousness. Still, there is no actual evidence of a causal connection between eating a particular food and Hawai‘i having averted a catastrophe. In practice, this is the same as trying to wish away the tropical storms.

In contrast to the Primacy of Consciousness, Ayn Rand discusses the Primacy of Existence. It starts with the most obvious observation you can make — something exists. Something that exists is called an “entity.” Your recognition that something exists will produce a corollary recognition: a consciousness exists — your own. Were it not for Existence, there would not be something there for your consciousness to recognize, and there would definitely be no consciousness there to recognize it. Likewise, were it not for Consciousness, there would not be anything to recognize the existence of itself or anything else.

Your consciousness is clearly important. But when it comes to your consciousness recognizing what is real and true, or at least theoretically possible, looking at Existence must be the starting point. In the realm of Existence — what I also call Nature with a capital N — we find there are some principles that apply consistently. The law of gravity is an example.

And every entity has attributes through which your consciousness can distinguish it from other entities. The pertinent attributes of an entity are what we call the entity’s nature. It is in a tree’s nature, for example, to consist of cells, to grow, and to release oxygen as it takes in sunlight to produce its own food. By contrast, it is not in the nature of a tree to transform into a 400-meter-long rhinoceros and stampede over a city. We discover the respective natures of entities through repeat observations with the senses.

Recognition of an entity by its pertinent attributes is the Law of Identity. Here is how you apply that law. You observe one entity, Entity 1, whose attributes allow you to place it in a particular classification, a particular category — the concept of it. Then you observe Entity 2, which shares the same pertinent attributes as the first entity. Applying the Law of Identity, you recognize Entity 2 as being of the same category as Entity 1.

Entities perform actions. A cloud above you is an entity, and it sending raindrops down upon you is its action. Actions are caused by the respective natures of entities. In the past, when you observed clouds become a very dark gray, these clouds followed up by raining upon you. Today you see another cloud that is a dark gray. Applying the Law of Identity, you predict that this dark gray cloud will likewise send rain.

Derivative of the Law of Identity is the Law of Causality. The fact that entities have particular respective natures is a fact that affects the events that these entities cause. When two entities are of the same type, A, and they are under the same set of pertinent conditions, B, the same stimulus, X, will cause them to react in the same manner, Y.

We have two mobile phones, A, that are similar enough in the pertinent context to be regarded as being of the same type. These are phones 1 and 2. Both of them are under the same condition, B — they are not broken. On Phone 1, I input your phone number. This is the stimulus or causal agent X. This results in your phone ringing, effect Y. Applying the Law of Identity, we ascertain that if, after you have hung up from the first call, I punch in your number on Phone 2 as well, it will likewise cause your phone to ring. We infer that the action of my inputting your number will be consistent in causing your phone to ring. As Ayn Rand phrases it, “The Law of Causality is the Law of Identity applied to action.”

These are the same sensory observations denigrated by metaphysical Idealism, epistemic Rationalism, and, implicitly, by all those who presume that their ability to imagine a scenario is sufficient to prove that it is possible.

Again, the vast majority of philosophy instructors will tell you that David Hume was a consistent empiricist. That is, he was the opposite of a metaphysical Idealist and epistemic Rationalist, of which Plato was both. If they could put aside their prejudicially motivated revulsion toward Ayn Rand long enough to learn her terminology, philosophy instructors would say that admirers of Ayn Rand’s should concede that Hume argued from “the Primacy of Existence.” But I find, sadly, that what Hume has said about imagination and theoretical possibilities is an instance of him showing favor to the Primacy of Consciousness.

In contrast to metaphysical Idealists, epistemic Rationalists, and — in this instance at least — David Hume, I shall now present my new argument about why a posited scenario must have evidentiary backing before it is to be welcomed as a theoretic possibility.

 

 
My New Way of Phrasing It
Again, many people in Hawai‘i say that it is theoretically possible that if we appease spirits on New Year’s Eve by eating a particular lucky food, those spirits will help protect us throughout the year. And, again, many people chirp that it is theoretically possible that their whole lives are an illusion and they are actually a brain in a jar being made to dream the dream that is their lives.

As with any supernaturalistic claim, these people begin by imagining a scenario arbitrarily, and then they try to rationalize it after the fact. This approach exemplifies the Primacy-of-Consciousness mindset. Now let us proceed from the other end. Let us acknowledge the Primacy of Existence.

We start off by looking at entities — the objects that exist. To speak of what is “possible” is to speak of a judgment made about some posited event. “Events” are just actions performed by the entities. That is why we look at the entities before we consider their actions and the events or possibilities associated with them. Moreover, the qualities of an action are influenced by the qualities of the entity performing it. Hence, it is only by learning about entities and their attributes that we ascertain what is possible for them.

That is why there is no proper basis or justification for us to speak of what is “theoretically possible” for an entity in the absence of observational knowledge of that entity’s attributes. Facts and evidence about an entity are epistemically foundational, and “possible” is a derivative attribute of that entity’s actions that hinges on such an epistemic foundation.

To be rationally justified, then, in saying that an event is theoretically possible is to say the following. It is to say that even if we are not sure that this particular event will take place, we have gained enough knowledge of the pertinent entities — enough evidence — for us to make an educated guess that they possess the necessary attributes that would enable them to contribute to the occurrence of this event.

As the biologist Meghann Ribbens put it to me, there is a good reason why, at least implicitly, we recognize the distinction between “imaginable” and “possible.” Some events that were indeed possible were, at some points in human history, unimaginable. It is doubtful that Stone Age hunter-gatherers imagined the occurrence of invisible airwaves that one day would transmit information to radios, televisions, and mobile phones. Conversely, as we have seen, not everything imaginable is possible. If there was no obvious distinction between “imaginable” and “possible,” there never would have been a need to coin the adjective imaginable; the adjective possible would suffice for every scenario ever described. And if every imagined scenario were possible, there would not need to be the adjective possible either — “possible” as opposed to what?

When someone floats an arbitrary postulate, such as that astrology predicts the future, often this person issues a particular challenge and advances a particular insinuation. The challenge is for any would-be doubter to put forth an effort to disprove the postulate completely. The insinuation is that, in the absence of such an effort, those who initially doubted the postulate must now concede that the postulate has gained clearance for admission into consideration as a theoretic possibility. Anyone who refrains from entertaining the postulate as deserving of consideration — even if that refraining was originally by passive default — is allegedly duty-bound to engage with arguments for and against the arbitrary postulate, on the pain of otherwise being exposed as intellectually lazy and intellectually dishonest.

It is that challenge and insinuation that are intellectually lazy and intellectually dishonest. There is no limit to the number of arbitrary postulates being foisted in our culture. Anyone who tried to engage with all or even most of them would waste all time on this pursuit, and partake in nothing else in life. On any occasion in which someone floats an arbitrary postulate, it is not incumbent upon me to poke holes in it to justify my passively refraining from entertaining that postulate as a possibility. When someone wants me to welcome the postulate as a theoretic possibility, the burden is on him or her to show evidence for the existence of conditions that can contribute to its occurrence. Thus, we do not rule out possibilities from limitless arbitrary imaginings. Instead we rule in possibilities based on their evidentiary support. 

There is only one set of circumstances in which we have a firm footing in ruling out what was previously considered a possibility. It is this. Initially, based on the knowledge we have, we rule in a set of theoretic possibilities, such as A, B, and C.  Then we conduct further investigation. Based on the additional knowledge, A and B still appear viable. However, the new information we have gained about the attributes of the pertinent entities exist in such a manner as to preclude C from happening. At that juncture, we can rule out C.  But insofar as any proposition is made in the absence of evidence, that proposition is not to be ruled either in or out as a possibility. It deserves simply to be ignored so that we can devote our precious time and attention instead to propositions that are buttressed by evidence.

That is why it is wrong — why it is the Primacy of Consciousness — when people start with some arbitrary imagining, call it “theoretically possible,” and then try to rationalize it after the fact. To understand the Primacy of Existence is to start with observations and facts. And it is after we learn about an entity’s capabilities that way, when we can apply imagination to imagine possibilities in such a manner that can actually get practical results.

 

 

 

What About People Who Accomplish What Was Previously Thought Impossible?
The Wright brothers provide an instructive case study in ascertaining what is and is not possible, and in imagination’s proper role in rendering such judgments. The Wright brothers were highly imaginative. They conceived of a heavier-than-air flying machine at a time when none had existed and in which the consensus was that such a product of their efforts would never take off — pun intended.

“We knew,” said Wilbur, the older Wright brother, “that men had by common consent adopted human flight as the standard of impossibility. When a man said, ‘It can’t be done; a man might as well try to fly,’ he was understood as expressing the final limit of impossibility.”

It was for such reasons that the prospect that the Wrights would succeed at flying was widely dismissed. It was dismissed even by the eminent physicist and entrepreneur Lord Kelvin, who played a major role in laying the first transatlantic telegraph cable and who provides the namesake of the scientific unit for measuring temperature. “...I have not the smallest molecule of faith,” he wrote, “in aerial navigation other than ballooning or of expectation of good results from any of the [aeroplane] trials we hear of.” 

In 1899, Scientific American magazine, too, expressed doubt. A major obstacle to the invention of the airplane was developing a method for safe steering. As the ability to duplicate the method by which birds steered themselves seemed unlikely, the periodical determined that aeroplanes would not have “commercial or military utility.”

In light of a spectacular failure of another experimenter, Samuel Pierpont Langley, attempting heavier-than-air flight, the New York Times pronounced in October 1903 that though such manned flight could happen one day in a far-flung future, it would not happen any time soon. “It might be assumed,” said the Times

“that the flying machine which will really fly might be evolved by the combined and continuous efforts of mathematicians and mechanicians in from one million to ten million years...”

That same year, on December 10, a second New York Times editorial stated that such a brilliant enthusiast attempting flight should not

“put his substantial greatness as a scientist in further peril by continuing to waste his time and money for further airship experiments. Life is short, and he is capable of services to humanity incomparably greater than can expected to result from trying to fly...”

A week later, the Wright brothers made their first flight.

To the dismissals in general, the younger Wright brother, Orville, retorted, “If we all worked on the assumption that what is accepted as true is really true, there would be little hope of advance.”

Of course, in their endeavor to prove it possible for humans to produce heavier-than-air flying machines, imagination was necessary but not sufficient. For what they imagined to manifest as possible, the Wright brothers always had to account for the evidentiary facts of Nature they observed. The reason why the Wright brothers were right. whereas Lord Kelvin and Scientific American magazine and the New York Times were wrong, was that when it came to this issue, the Wright brothers took all the pertinent evidence into consideration much more logically and consistently than did Lord Kelvin, Scientific American, and the New York Times.

What the Wright brothers understood to be “theoretically possible,” at least implicitly, was (a) what they imagined and (b) what they understood to be within the at-least-general bounds of evidence.

Here is a story that is an example of that. To make their first tests on the wings of their contraption, they produced a large kite — the “glider.” The first airplane would have a motor, but, as far as their early experiments were concerned, the glider did not need one. They took the then-motorless glider to Kitty Hawk exactly because its strong winds would carry the glider. In these experiments, they initially relied on “lift tables” provided by another aviation experimenter, Otto Lilienthal.

Lilienthal had experimented on using different shapes for his airfoils — objects to sustain lift in flight, such as wings and tail rudders. The tables were the records he made for the lift-to-drag ratio for each of the various airfoil shapes. Eventually, the Wright brothers noticed major discrepancies between Lilienthal’s lift tables versus their own results. Rather than take the lift tables on faith, the brothers had to admit to themselves that the tables were inaccurate. They therefore had to apply both their imaginations and empirical knowledge to develop their own lift tables.

Their bicycle shop proved fortuitous in this. They built their own small wind tunnel out of wood. A 1-horsepower engine from their bike shop powered a fan that produced airflow. Out of bicycle spokes and hacksaws, they assembled a “lift balance.” Mounted on top of the lift balance would be (1) an airfoil section they intended to test and (2) a flat plate with a surface area equal to that of the airfoil section. As the airflow impacted upon them, the respective torques of the airfoil section and the equivalent-surface-area flat-plate had to be equal to one another. When the respective torques were equal, the Wrights were able to make accurate measurements of lift-to-drag ratio for 48 different airfoil sections.

Observe the need for both logic and imagination even in just these wind-tunnel experiments. The Wrights had to be logical in accepting the faultiness of Lilienthal’s lift tables. They had to be imaginative in devising their own wind-tunnel experiments. And they needed both imagination and logic to understand how this wind-tunnel model would apply to the actual airplane’s flight later on. This smaller part, and the wider project overall, required both logic and imagination.

It was through such empirical observation that the Wright brothers gained further confidence that the flight of an airplane was indeed possible. Orville said, “I believe we possessed more data on cambered surfaces, a hundred times over, than all of our predecessors put together.” Note his mention of data — as in “sensory evidence.” The data came first — and, from it, the Wrights could ascertain what was, and what was not, theoretically possible. Here, we see that, although “theoretic possibility” is permeated with many still-unknowns, it remains within parameters set tentatively by what is known, including that which is recently-discovered.

Four years before the first flight, Wilbur Wright wrote to the Smithsonian Institution asking for information on what had already been tried. His letter touched implicitly upon the basis in evidentiary support for any theoretic possibility. “I am an enthusiast, but not a crank in the sense that I have some pet theories as to the proper construction of a flying machine. I wish to avail myself of all that is already known and then if possible add my mite [own information-gathering]...”

Yes, de facto, the Wright brothers’ approach was Facts come first; then we apply those facts to imagine the possibilities.

 As my late father wrote on January 19, 1973, “An idea is not a reality. An idea is a method of perceiving reality.”

 

The Fallacies in Saying “Maybe Our Sensory Experiences Are a Distortion of Reality, and We Are Ignorant of What Is Actual Reality”
I now want to give special attention to the arbitrary postulate that perhaps everything our senses tell us is a misleading distortion, and that there may be a truer reality that exists beyond our ability to perceive anything. According to this postulate, what our senses inform us is not reality but merely a representation of reality — or, more precisely, a misrepresentation of reality. This postulate is an obfuscation of the very means by which we identify what is a representation or misrepresentation of anything.

To say that R is a representation of Q is to say that R is not literally Q but that R at least symbolizes Q in our minds. Moreover, we know R is a representation of Q because it has enough pertinent similarities in attributes with Q for us to recognize R as representational of it. For instance, we know that a toy truck from the brand Hot Wheels or Micro Machines is not literally a truck. But a toy truck from Hot Wheels or Micro Machines provides enough visual and other sensory cues for us to recognize the toy as a representation of a truck.

Here is a pertinent question. If you present a toy truck to a baby before she has ever seen a real truck, will she recognize the toy as a representation of a truck? She will not. You can recognize R as a representation or simulation of Q no more than the extent to which you have knowledge of what Q itself is like literally.

The same principle applies when we talk of a misrepresentation, or at least a representation that has been found to be inaccurate. Consider how whales are depicted on maps of the Atlantic Ocean that were drawn during the high Middle Ages. Of importance here are some facts about whales that became well-known in the twentieth century. First, whales do not possess scales like those of carp — goldfishes and koi — and the arowana fish. Also pertinent are tail flukes — these are the triangle-shaped parts of the tail fin found on fishes and whales. On whales, the tail flukes are horizontal — there is a fluke on the left and another on the right. By contrast, when a fish has tail flukes, they are more likely to be vertical — there is a fluke on the top of the tail and maybe another on the bottom. Not all fishes have vertical tail flukes, but it is the case that all whales only have horizontal tail flukes.

Now take a gander at a medieval map of the Earth and its oceans, and examine what that map labels a whale. Conventionally, the “whale” will be covered in fishlike scales and sport tail flukes that are vertical like a fish’s, not horizontal. These are inaccuracies in representation. The charitable way to interpret this is that the map’s illustrators labored in earnest and the inaccuracies came from their not having the information about whales that became more accessible from the twentieth century onward. But whatever the cause of the inaccuracies, we know of the representation’s inaccuracies only because we have some knowledge of what actual whales are like.

 

 Thus we discern the illogic in someone saying that all our sensory experiences are no more than a representation of reality, whereas the truer reality is unknown to us. We can discern something as a representation of objective reality no more than the extent to which we have already experienced objective reality directly and thereby gained knowledge of it.

Further, we can discern the even-bigger fallacy in proclaiming that our sensory experiences might be a false representation of an alleged truer objective reality that remains unknown. For us to have a basis in speculating that our sensory experiences might not match reality exactly, once again we would have to know what objective reality is like literally. And yet in this scenario we have already been told that we are wholly ignorant of that very same objective reality.

 

 
Conclusion
When someone proclaims, “It’s theoretically possible that all our sensory experiences are deceptive or unreal, and we are in complete ignorance of reality as it truly is,” that proclamation remains wholly arbitrary. And it is to be written off as such.

In sum, the existence of entities and the facts associated with them are primary, and to discern what is theoretically possible for those entities is contingent upon those facts. That is why, just because you can imagine something happening, that is not sufficient for calling it a “theoretic possibility.”

On Friday, August 4, 2023, I added the part about Scientific American magazine. On Monday, August 7, 2023, I added the paragraph about how, subsequent to ruling in a theoretic possibility with the evidence we had at the time, C, we are justified in ruling out C as a possibility upon our discovering further evidence that precludes it. That same day I embedded the YouTube video about how many animals were represented inaccurately in the European-authored bestiaries of the high Middle Ages. On Sunday, June 2, 2024, I added the quotation from my father. On Saturday, September 7, 2024, I added the case study of what the Wright brothers did about the lift tables.