Do I Really Exist?

The following is an excerpt from Proof: The Rational Case for God, by Barry B. Kaplan.

The book grew out of a challenge from an atheist friend who insisted that the question of God lies entirely outside the bounds of reason. What followed was a seven-year investigation across philosophy, probability, cosmology, consciousness, history, and classical Jewish thought, aimed at a single foundational question: is belief in God rationally defensible? Kaplan begins with this question because everything that follows depends on it.

How do you know you exist?

On the surface, the question may sound bizarre, but it is one of the most fundamental challenges of philosophy. Everything you believe—about the universe, about yourself, about reality—rests on the assumption that your perceptions reflect objective truth. But how can you be so certain?

For thousands of years, philosophers have questioned whether we can trust our senses, whether reality is as it seems, or whether we are trapped in an illusion, a dream from which we can never wake.

Judaism, too, addresses this question. But before arriving at a Torah perspective, we must first consider the problem itself.

Plato’s Cave and the Nature of Reality

Millennia ago, Plato¹ presented his Allegory of the Cave, a powerful metaphor for human perception and belief, which we summarize as follows:

Imagine a group of prisoners chained to the ground in a dark cave, placed there since birth, directly facing a wall. They cannot turn their heads or move around. Behind them, a fire burns. Shadows of objects, carried by unseen figures, project onto the wall in front of them. These shadows are all the prisoners have ever known. To them, the shadows are reality.

One day, a prisoner is freed. He turns to see the fire. At first, it blinds him. Then, he realizes the shadows were mere projections, not reality itself. When he ventures outside the cave, the sunlight is overwhelming. But slowly, his eyes adjust. He sees the world in all its color, depth, and complexity. He discovers that the cave was an illusion, a mere fragment of a much greater truth.

Soon, he returns to free the others. But instead of welcoming his gesture, they do not believe him. They still see only the shadows and cannot conceive of anything beyond them. They mock him for his audacious claims. If he persists, they might even kill him.

Plato’s message is clear: We mistake our limited perception for true reality. The world we think we see may be only shadows; an approximation of a far deeper, more complex existence.

Consciousness and Descartes

Two thousand years later (1641), René Descartes, renowned mathematician, scientist, and philosopher, published Meditationes de Prima Philosophia (Meditations on First Philosophy), his short six-part groundbreaking treatise. This monumental philosophical work, still introduced in contemporary philosophy courses, profoundly shaped the trajectory of Western thought.

I first encountered Descartes’ Meditations in a Philosophy 101 lecture three decades ago, seated amongst several hundred other inquiring students, all grappling with the radical challenge he posed: What, if anything, can we know with absolute certainty?

Radical Doubt

It is sometime in the late 1630s. Darkness falls in the Dutch Republic. We can picture Descartes sitting alone in a modest rented room, one of several he moves between in towns like Amsterdam and Utrecht. He values such solitude, shunning fame and distraction so that he may pursue his epistemological line of reasoning peacefully. A candle flickers on his stately desk, its light catching the curves of ink pots and the edges of parchment. The air is still, broken only by the scratching of his quill and the faint creak of timbers in the fire.

Here, in these quiet nighttime hours, Descartes sets out to question everything, to doubt every assumption until nothing remains but what cannot be denied. From that silence emerges a most daring project: to rebuild knowledge itself, beginning with the Meditations on First Philosophy.

He starts with the most immediate source of information; the senses. Surely, that which we see, hear, touch, taste, and smell are reliable indicators of reality?

But are they really? He recalls that his senses have deceived him in the past; objects appear bent in water,² mirages³ shimmer in the desert, dreams sometimes feel indistinguishably real.

Could it be that right now, he is dreaming? If he has ever mistaken a dream for reality, how can he be so sure that this very moment is not another one of these illusions? Perhaps nothing his senses tell him is to be trusted.

But he does not stop there. He imagines a more extreme scenario: What if an all-powerful, malevolent being, a deceiving demon, if you will, were manipulating his mind, presenting him with false experiences? If this were possible, then he cannot trust anything he perceives.

Including mathematics:⁴ Perhaps this deceiving demon wants him to believe that 2+3=5, not because it is true, but because he is being deceived even in the realm of pure reason. For Descartes, the point is not that math is or even could be wrong, but that if deception is possible even in such seemingly clear truths, then certainty must be grounded in something deeper.

At this moment, for Descartes, the external world completely dissolves. His surroundings, his own body, even the laws of nature; everything is cast into doubt. He has stripped reality down to its essence. But then, amid this radical doubt, a singular certainty emerges: He is thinking.

I Think, Therefore I am

Even if he doubts everything, the very act of doubting confirms his existence. If there is deception, there must be something, some mind-entity—being deceived. If he is thinking, he must exist. “Ego sum, ego existo,”—“I am, I exist.” The realization is better known via his more famous dictum: “cogito, ergo sum.”—“I think, therefore I am.” That statement was introduced in his earlier Discourse on Method but further developed in the Meditations.

This is no trivial insight. It sets up the self; not as a body, but as a thinking thing (res cogitans). No matter how unreliable human senses are, the existence of the mind is beyond dispute.

Contemporary philosophers further refine this dictum: Something that thinks exists. This is the bare minimum for existential certainty.

Thus, when all is said and done, there is, at the very least, a mind-like entity—some “self” that experiences thought. This simple truth, derived from pure reasoning alone, is still one of the most profound insights in philosophy.

Why not “I play basketball, therefore I am?”

Some might ask: if thinking proves existence, why not any action? Why not say, “I play basketball, therefore I am?” The revised question is not meant to trivialize the concept, but to highlight the distinct problem of awareness.

The answer lies in the nature of thought itself. Descartes’ insight was not about action, but about indubitable awareness. Thought, or more accurately the act of thinking, is a self-verifying activity. Questioning, doubting, and reflecting, are actions only a conscious subject can perform. Therefore, a conscious subject or thinking being must exist. Thought equals existence.

“Playing basketball” presupposes an external world, a functioning body, a court, a ball, other players, and reliable senses; all of which can be doubted. You might dream you are playing basketball. You might be in a digital simulation playing basketball. But you cannot doubt that you are thinking, even if your thoughts are wrong or manipulated.

Thought is the only activity that proves a thinker exists even in the absence of any external reality.

So, we arrive, not at “I exist,” but at something more modest and more honest: Thought exists.

Some kind of thinking is occurring. That much is irrefutable, because even the act of denial confirms it.

But the identity of the thinker? Uncertain. The reality of the world? Unproven. All we really know with absolute clarity is that something is happening, and it involves thought.

But now we ask a far deeper question; one that Descartes never fully addresses: Why should anything exist at all? Why should there be thinking, or matter, or time, or motion, or anything whatsoever? Why not nothing? It is this unsettling question that brings us to our next challenge.

Why Does Anything Exist at All?

Descartes shows that thought is undeniable; now we consider why there is any arena, be it mental or material, in which thought occurs?

The Cosmological Argument

Start with what is known: something exists. Not necessarily “you,” not necessarily this world, but something. There is some form of being, some reality, however uncertain or abstract.

And within that something, there is thought. Thinking is happening, and that is undeniable. It may be fleeting or confused, but the thinking “event” is real. So now, we are not asking who or what exists. Instead, we are asking the deeper question: Why should there be anything at all?

Why is there being? Why not nothing?

This is the question that generates the cosmological argument, an ancient line of reasoning that rejects “just because” as a valid answer.

The universe could have been otherwise. Or not at all. You could have never existed. The laws of nature could have been different. Atoms did not have to arrange themselves into galaxies, rocks, trees, bees, and nervous systems. And yet, here they are. Here you are. That is called contingency; the quality of being dependent, conditional, not necessary. And the cosmological argument simply asks: Can all of reality be contingent?⁵

What holds up the entire system if every part leans on something else? At some point, we must reach bedrock, foundation, source; something non-contingent. Something that does not just happen to be but must be. Otherwise, we have built the universe and our concept of reality on an infinite chain of borrowed explanations; like trying to suspend a chandelier from an endless series of hooks, each one hanging from the next, but none of them anchored to the ceiling.

We do not need theology for this part, just pure logic and reasoning.

• Contingent things exist.
• Contingent things require explanations.
• An infinite regress of contingent explanations explains nothing.
• Therefore, there must be at least one necessary⁶ thing.

That necessary thing—that “something” which does not depend on anything else to exist—is what we mean by a Necessary Being. And in the Jewish tradition⁷ and similar monotheistic traditions, that Being is God.

Not a human-shaped God. Not a lightning-throwing gray-bearded sky-dweller; but a pure, necessary, sustaining Source. Being itself.

Rav Saadia Gaon⁸ argued for a Necessary Being a thousand years ago. Maimonides honed it further.⁹ In the 1940s, Gödel¹⁰ developed a modal logic version of the ontological argument, later formalized and checked by computers. But its assumptions are controversial, and its conclusion overlaps with the cosmological argument already herein presented.

Some people try to avoid the question entirely by saying, “Maybe the universe is just a brute fact.” But if you allow for brute facts; inexplicable, arbitrary realities, then you have abandoned reason itself. You have said: “Some things just are. Do not bother to ask why.”

The entire project of science, philosophy, and meaning rests on the idea that all things happen for reasons. The cosmological argument does not prove everything. It does not tell us about commandments, or love, or covenant. It does not explain suffering or prophecy or what God wants from us.

But it gets us past the first hurdle. It tells us this: something necessary exists; something that must be and upon which everything else depends.

What Kind of Being Must Exist?

We have covered a lot of material quite rapidly. Let us take a quick mental breather to review.

• We do not know who the thinker is.
• We do not even know what kind of world we live in.
• All we know, all we can say with certainty, is that something exists, and that this something is not nothing.
• Thought is obviously happening. Something just thought this sentence. And contingency surrounds us. Some necessary foundation exists that explains why anything exists at all. Something that does not borrow existence from anything else.

But now deeper questions arise: What kind of “something” are we talking about? Is this Necessary Being a force? A law? A consciousness? Powerful? Perfect? If we stop short of asking these questions, then we have stopped just shy of the finish line.

The Ontological Argument

The ontological argument picks up right where the cosmological argument leaves off. It seeks to ascertain the “necessary being.”

And here is its surprising conclusion: If something exists necessarily, independent of anything else, unlimited, and self-sustaining, then by definition, it must be perfect.

Why?

Because limits imply dependence on something else.

If something is limited, then that limit must come from somewhere. If it is imperfect, then something must be withholding or restricting its perfection. And if something else is doing the restricting, then the thing is no longer absolutely necessary, it is conditioned by something beyond itself.

But a Necessary Being cannot be caused, shaped, or restricted by anything else. It must contain its full reality within Itself; unlimited, unbounded, unconstrained.

So, it must not just exist. It must be the greatest possible kind of existence.

Perfection. Absolute Perfection.

Not wishful thinking—logic.

To be clear, this is not about wishing that God is perfect. This is about understanding what the word “necessary” actually means.

Necessary existence is not just a status. It is a nature. A necessary being cannot fail to exist, it cannot depend on anything, and it cannot be missing anything. Otherwise, it would not be necessary, it would be contingent, just like everything else.

So, necessity leads naturally to a series of conclusions about the Being:

• It must be one; singular, because two necessary beings would require something to distinguish them.

• It must be immaterial because material things break down, change, and rely on space and time.
• It must be conscious, because intelligence is a form of perfection, and the necessary being cannot lack any perfection.
• And it must be maximally good,¹¹ because goodness is not a defect; it is a quality of wholeness. A flawed being would have limitations. The Necessary Being cannot be flawed.

That is the ontological position; not that perfection is likely, or poetic, or traditional. But that it is required by logic if the being in question truly exists necessarily.

An objection is heard:

“A perfect being must exist! What? You cannot just define something into existence. Just because you say it is perfect does not make it so.”¹²

If that is what we were doing, you would be right. But that is not the argument being made. We are not defining God into existence. We are asking: If something exists necessarily, what must that something be like?

And the answer is: It must be maximally real; maximally actual; maximally whole. Perfect.

The Necessary Being is no longer just an abstract force. It is a Perfect Being. And if it is perfect, then it must have all the attributes of perfection—Consciousness. Intelligence. Will. Plus, all the other attributes of Perfection.

Perfection is not mechanical. It is not blind. It includes knowledge, agency, and goodness. Which means that this Being; the one whose existence we have already concluded must be, is not just a background condition for the universe. It is not an amorphous “Perfect It.”

It is a Perfect Who.

This does not prove the God of Abraham. Or the God of Sinai. Or the God of the Torah. But it brings us so much closer. It tells us that the foundation of existence is not an indifferent void or a blind mechanism. It is a perfect, necessary, unlimited mind, a Conscious Source of all things.

Summary

• Something must exist necessarily.
• A necessary being cannot have limitations. Why? Limits imply dependence, and dependence contradicts necessity.

Therefore, a necessary being must be unlimited.

• Limitlessness includes perfection.
• Perfection includes consciousness, will, and goodness.

Therefore, the necessary being must be Perfect and personal. This, in brief, is the ontological argument. Not just some-thing exists, but a Perfect Some-One.

Peeling Back the Layers

These ideas may seem incredibly abstract, but they force us to confront, sometimes for the first time, something deeply personal: we cannot take existence for granted. To exist is not trivial. It demands explanation. And as we continue to peel back the layers of perception, we arrive at an even more disturbing possibility: not only are we contingent, but even our sense of reality may be completely unreliable.

Are We Living in The Matrix?

Plato’s Allegory of the Cave, Descartes’ Meditations, and the cosmological and ontological arguments are not merely ancient thought experiments, they each confront a disquieting possibility echoed in both modern science and popular culture: that reality itself may be illusory. The blockbuster film, The Matrix (1999), takes the idea to its ultimate extreme, depicting a world in which most of humanity is unknowingly trapped in a simulation. What people see, hear, and touch is not real, it is a digital construct generated by advanced super-intelligent machines.

Neo, the film’s protagonist, senses that something is wrong with the world. When suddenly confronted with the choice between illusion and truth, he chooses to pursue the truth, takes the red pill, and wakes up to a reality far more complex and unsettling than he ever imagined.

But this is not mere science fiction. Today, a number of mainstream philosophers and physicists take seriously the possibility that our universe could itself be a kind of simulation, at least as a hypothesis worth analyzing.

The Holographic Universe

Contemporary physics offers an intriguing theory eerily reminiscent of Plato’s cave. Called the Holographic Principle, it emerges from the investigation of black holes, ¹³ and it has reshaped our understanding of the cosmos.

When an object falls into a black hole, the laws of classical physics seem to say that its information—the blueprint of what it is and how it was arranged, is lost forever. But quantum physics insists that information cannot simply disappear. This clash led physicists like Stephen Hawking, Gerard ’t Hooft, and Leonard Susskind to a startling conclusion: all the information about what falls into a black hole isn’t destroyed but is instead, encoded on the black hole’s surface, the event horizon.

If that is too abstract, imagine crumpling a newspaper and tossing it into a fireplace. The paper burns, and the flames twist, lift, flicker, and change shape. But now imagine that this fireplace is not just a place where things combust, it behaves just like a black hole. In this hypothetical case, every flame flicker encodes something about what was incinerated. The newsprint and paper are destroyed, but somehow, the flames carry a trace of every letter, every fold, every detail, written onto their flickering surface. This is what the holographic principle proposes: that everything inside a black hole is not lost but encoded on the event horizon.

The astonishing leap: If this holds true for black holes, what about the entire universe? The Holographic Principle proposes that the entire three-dimensional universe, spacetime¹⁴ and all that lies within it, might be nothing more than a projection from a distant, two-dimensional boundary. Our reality, with its depth and richness, would be just like a hologram:¹⁵ a three-dimensional illusion arising from and projected via two-dimensional data.¹⁶

That sounds a lot like metaphysics to me.

To better conceptualize a hologram, think of the iridescent security label on credit cards: A thin, flat shimmering 3D surface holding information needed to confirm its authenticity. In a cosmic sense, our “thickness” and “substance” may be projections from a far-off, ultra-thin cosmic screen, projecting us into a three-dimensional perceived reality.

Physics Meets Philosophy

This theory is not merely speculation. Physicists take it seriously, exploring the nature of space, time, and information. If the universe is holographic, what we see, feel, and experience may be mere “shadows” of a deeper, more fundamental reality, just as Plato imagined.

• The Holographic Principle bridges quantum mechanics and gravity, two of the deepest mysteries in science.
• It raises profound philosophical questions: Are we living inside a vast illusion? Is the self merely projected data on a cosmic boundary?
• In Judaism and other spiritual traditions, there are echoes of this insight: what appears tangible or real may be only the outer layer—a projection, or a veil, with a much deeper truth concealed beneath.

Proof: The Rational Case for God is a structured, analytic examination of belief, written for thoughtful skeptics and intellectually honest believers alike. It does not ask for faith without evidence, nor does it dismiss belief by assumption. Instead, it asks what we are justified in believing, given the world as it actually is.

The book is available now from Amazon and other book sellers: https://www.amazon.com/Proof-Rational-Case-Barry-Kaplan/dp/B0GCKX7QHG/friendsofaishhat

1. Plato (c. 427–347 BCE) was a Greek philosopher and one of the most influential figures in Western thought. A student of Socrates and the teacher of Aristotle, he founded the Academy in Athens—one of the earliest institutions of higher learning. His writings, primarily in the form of dialogues, explore subjects such as metaphysics, ethics, politics, and epistemology (the theory of knowledge). Among his most famous works is The Republic, in which he outlines his vision of an ideal society and presents the Allegory of the Cave, a metaphor for human perception and enlightenment, framed as a discussion between Socrates and Glaucon. His philosophy, particularly his theory of Forms, the idea that the physical world is merely a shadow of a higher, unchanging reality, has profoundly shaped Western philosophy, theology, and science.
   Glaucon was a young Athenian nobleman, the brother of Plato, and one of Socrates’ interlocutors in Plato’s Republic. He is best known for pressing Socrates to defend the value of justice—not merely as a social convenience, but as something good in itself. In Book II of the Republic, Glaucon challenges Socrates with a famous thought experiment: the Ring of Gyges, which grants its wearer invisibility and thus the ability to act without consequence. Glaucon argues that even a just person would act unjustly if he could do so without being caught, implying that people are only ‘just’ out of fear of punishment or loss of reputation.
   This challenge prompts Socrates to deliver the central argument of The Republic: that justice is intrinsically better for the soul, leading to harmony and inner order, while injustice corrupts and disintegrates it.
2. The apparent bending of a straw in water is caused by refraction; the change in direction of light as it passes between media, in this case from water to air. Because light travels more slowly in water than in air, it bends at the interface, making the submerged part of the straw appear offset from the part in the air. This optical illusion is governed by Snell’s Law (but is described earlier by others), which relates the angle of incidence to the angle of refraction.
3. Mirage—an optical illusion caused by the bending of light (refraction; see earlier footnote) as it passes through layers of air with differing temperatures. This phenomenon often occurs in deserts or on hot roads, where distant objects—such as water, trees, or even entire landscapes—appear distorted, displaced, or reflected. While physically real as a “light effect” a mirage is misleading, making something appear where it does not actually exist materially.
4. Descartes’ suggestion that a deceiving power might mislead him is not an argument that 2+3 could ever equal anything other than 5. By the very definitions of number and addition, the result is necessary. What the thought experiment challenges is not the truth of arithmetic itself but the reliability of our recognition of that truth. The imagined demon cannot alter the structure of numbers—that would be a logical impossibility—but it could, in principle, cloud our perception so that even the most obvious facts appear doubtful. An analogy may help: A warped mirror cannot change the shape of your face, but it can make you see it as distorted. Likewise, the demon cannot change mathematics, but it could make us mistrust even the clearest and most obvious calculation. Descartes presses this extreme possibility to show that certainty must be grounded in something deeper than calculation.
5. Contingent (from the Latin contingere—to happen or befall) refers to anything whose existence is not required logically or metaphysically. A contingent thing exists, but it could have failed to exist. It depends on external conditions or causes. For example, a tree exists because a seed grew in the right soil under the right conditions, but nothing about the tree requires that it must exist in all possible circumstances. Most things in our experience—stars, animals, people, even the universe as a whole—are understood to be contingent. The central insight of the cosmological argument is that if everything were contingent, then nothing would exist at all, unless grounded by something non-contingent.
6. A necessary being is one whose non-existence is impossible. It exists by its very nature, it does not “happen to be,” but must be. It depends on nothing outside itself, and its essence includes existence. Unlike a contingent thing (which could be otherwise), a necessary being exists in all possible realities.
   This concept underpins both the cosmological argument, which posits that the chain of contingencies must terminate in a necessary source; and the ontological argument, examined later, which holds that a maximally Perfect Being would be necessary by definition. In both, necessity is not an optional feature, it is the only coherent endpoint for explanation. All contingent things are receivers of being, but there can be only one necessary Presenter.
7. Judaism teaches that the Torah addresses not only Israel but all of humanity. Long before Sinai, God established a covenant with Noah and his descendants, binding on every human being. This covenant is expressed in the Seven Noahide Laws: the prohibitions against idolatry, blasphemy, murder, sexual immorality, theft, and eating flesh from a living animal, together with the obligation to establish courts of justice. These laws form a universal moral code, demonstrating that one need not be Jewish to live a life of Divine purpose.
   Judaism does not seek to convert the world; on the contrary, the Torah’s vision is that humanity fulfills its role through these seven commandments, while Israel fulfills its role through the 613 mitzvot (commandments). Maimonides rules (Hilchot Melachim 8:11) that any non-Jew who accepts and observes the Noahide Laws because they were commanded by God through Moses is counted among the “righteous of the nations of the world” and merits a share in Olam HaBa (the World to Come). Indeed, there are communities of Noahides today—non-Jews who consciously live by these laws as their covenant with God—embodying the Torah’s teaching that eternal reward is open to all humanity.
8. Saadia ben Joseph, better known as Rav Saadia Gaon (882–942 CE)—was a leading rabbinic authority, philosopher, and exegete of the Geonic era. Serving as Gaon (head) of the Sura Academy in Babylonia, he was among the first Jewish thinkers to systematically integrate Torah scholarship with rational philosophy, defending Jewish belief through logic, grammar, and biblical commentary.
9. See Emunot VeDeot (Book of Beliefs and Opinions) by Rav Saadia Gaon, Ma’amar 1, where he presents a rational proof for the existence of a Creator based on the impossibility of infinite regress and the contingency of the universe. Maimonides builds upon this in Moreh Nevuchim (Guide for the Perplexed), Part II, Chapters 1–4, arguing that a necessary being—who is neither material nor composite—must underlie all existence.
10. Kurt Gödel (1906–1978), the brilliant Austrian American logician best known for his Incompleteness Theorems in mathematics, also drafted a version of the ontological argument in the 1940s. Using modal logic (the logic of possibility and necessity), he defined God as a being possessing all “positive properties,” and reasoned that if such a being is possible, then it must necessarily exist in every possible world. Gödel’s handwritten axioms were incomplete and somewhat ambiguous, and later philosophers discovered that, taken at face value, they lead to “modal collapse”, the controversial result that all truths become necessary truths. In the 1970s Princeton logician Dana Scott produced a clarified and formally precise version of Gödel’s notes, which has since been verified by modern computer proof-checkers.
    Even so, the argument rests on highly contested assumptions—not least what counts as a “positive property,” and whether such properties can be assumed to be mutually compatible. As a piece of formal philosophy Gödel’s proof is elegant, but most scholars regard it as more of a logical curiosity than a decisive demonstration of God’s existence. In Gödel’s system, a positive property is a kind of perfection or intrinsic excellence, and Gödel assumes that “necessary existence” is among them. If such a being is possible, the proof succeeds; the difficulty is that these foundational definitions remain deeply controversial.
11. The English word good comes from Old English gōd, meaning “virtuous, desirable, fitting, having the right or proper qualities” (Oxford English Dictionary, and others). In philosophy, Plato identifies “the Good” (Agathon, Greek for “the Good”) as the ultimate reality that gives truth and value to all else (Republic VI, 508e–509b), while Aristotle calls the good “that at which all things aim” (Nicomachean Ethics I.1, 1094a). Aquinas later framed it as “that which all desire” (Summa Theologica I, q.5, a.1), identifying goodness with the perfection of being itself.
    In Hebrew Scripture, the word for good— טוב (tov), appears in the opening chapter of Genesis: “And God saw that it was good” (Genesis 1:4). Later, when the text declares creation to be “very good” (Genesis 1:31) ancient commentators explain that this included even what seems negative: mortality, judgment, and struggle. In this sense, tov means not simply pleasant or agreeable, but fully aligned with the ultimate purpose of Creation, encompassing both the obvious and the hidden dimensions of life.
    Thus, when I write that a perfect, necessary Being must be good, I mean both in the philosophical sense—the highest object of desire, value, and moral order—and in the Scriptural sense of tov: existence perfectly ordered toward its ultimate purpose, including even those aspects that surpass human comprehension.
12. Immanuel Kant (1724–1804) championed this protest. His objection: “existence is not a predicate.” To say that God exists does not add a new property to the concept of God, any more than saying “a hundred real dollars” adds something to the concept of “a hundred dollars.” The difference is not in the definition but in whether such a thing exists outside the mind. Thus, Kant rejected the attempt to prove God’s existence by definition alone.
    This is not the argument made here. The question is not whether we can define God into reality, but rather: if there exists a necessary being—something that “cannot not exist”—what must that being be like? The conclusion is not a definitional trick, but a reflection: such a being would be maximally real, maximally actual, maximally whole. Perfect.
13. A black hole is a region in space where gravity is so strong that nothing, not even light can escape. It typically forms when a massive star collapses in on itself, squeezing all its matter into a tiny, incredibly dense point called a singularity. Surrounding this point is the event horizon, an invisible boundary marking the “point of no return.” Once something crosses it, there is no way back. Black holes are predicted by Einstein’s theory of general relativity, which describes how gravity can bend space and time. They come in assorted sizes; smaller ones formed by dying stars to supermassive black holes that sit at the centers of galaxies, including our own Milky Way.
14. Spacetime is the single, continuous fabric that weaves together space and time into one unified whole. Instead of treating space as a static stage and time as a separate clock, Einstein’s theory of relativity revealed that they are deeply intertwined: the geometry of space is shaped by the flow of time, and the passage of time depends on the structure of space.
    Every event in the universe—from the fall of an apple to the orbit of a planet—happens not simply somewhere in space or some moment in time, but at a specific point in spacetime. Massive objects curve this four-dimensional fabric, and that curvature tells other objects how to move—what we perceive as gravity.
    In essence, spacetime is the living architecture of the universe, connecting where and when everything exists and interacts.
15. A hologram is a three-dimensional image created by the interference of light waves. Unlike a regular photograph, which captures only the intensity of light, a hologram records both the intensity and phase of light waves, allowing it to recreate the illusion of depth and perspective. This is achieved through a process called holography, which uses laser beams to encode and reconstruct the image. The result is an image that appears to float in space, and is viewable from different angles, much like a real object.
16. Some physicists have proposed that our universe may resemble the interior of a white hole—the time-reversed twin of a black hole. Instead of collapse ending in a singularity, they imagine a rebound that erupts as expansion. If so, the Big Bang could be seen as the bursting-forth of a created white hole. But even then, the question of origin remains: such a white hole would still need to be called into being, with its laws and limits already in place.<spa