The Future: A Human Invention According to Physics, Neuroscience, and Philosophy

Introduction

Time is a mysterious and fundamental aspect of our experience, yet its true nature remains elusive. A provocative idea is that only the past and present truly exist, while the future does not exist independently of our minds. In this view, the future is not a tangible part of reality but rather a projection — a construct that humans create through expectation and imagination. This essay explores that idea from multiple angles, drawing on insights from physics, neuroscience, and philosophy. By examining what modern science and thought tell us about time, memory, and reality, we can better understand the thesis that the future has no concrete existence of its own and lives only in our anticipations.

Physics: Time, Reality, and an “Open” Future

In physics, the nature of time has been debated for over a century. Albert Einstein’s theory of relativity treats time as a dimension much like space, leading to the concept of a “block universe” where past, present, and future events all coexist in a four-dimensional continuum (1). In a strict block universe interpretation, the future is just as real as the present — it’s already “there” in space-time. However, not all physicists agree with this interpretation. Many argue for a more commonsense picture: that the past and present exist, but the future is not yet real. This perspective aligns with our everyday intuition that the future is open and not fixed until it happens.

A compelling argument for an “open” future comes from the combination of relativity with quantum physics. Physicist George Ellis, for example, has suggested an evolving block universe model, where the present marks the boundary between a fixed past and an undetermined future. “The past is real and can have had an effect on us today,” Ellis explains, “but the future cannot influence us because it does not yet exist” (1). In this view, time is like a growing stack: with each moment, another layer of reality (the present) is added to the pile of an ever-expanding past, while the future remains a realm of mere possibilities. Crucially, this idea does not conflict with Einstein’s equations; it simply interprets them in a way that doesn’t assume the future is already written (1). The flow of time, under Ellis’s model, is real and marks the constant unfolding of new events that weren’t previously concrete.

Hippocampus from DK atlas. Generated using BrainPainter https://brainpainter.csail.mit.edu/

Figure: The human brain’s hippocampus (colored region) is crucial for imagining future events. In physics, by contrast, time is often modeled as a dimension in which all events (past or future) are laid out. Some scientists, however, argue that only the present “slice” of time is real, with the future being a set of possibilities that have yet to materialize. (1) (2)

Quantum mechanics provides further support for the idea of an indeterminate future. Unlike classical physics, quantum physics says that we cannot predict certain events with certainty; we can only calculate probabilities. Prior to being observed or measured, a system exists in a superposition of multiple possible states. This inherently probabilistic nature means the future “exists” only as a range of potential outcomes until one becomes reality. Stephen Hawking put it succinctly: “Quantum physics tells us that… the (unobserved) past, like the future, is indefinite and exists only as a spectrum of possibilities” (2). In other words, at the fundamental level described by quantum theory, there is no single, definite future in existence — only a haze of potential futures. It’s only when events become present (through observation or interaction) that one outcome crystallizes into reality. Hawking’s point underscores that even the past isn’t absolutely concrete until measured, but it especially emphasizes the status of the future as nothing fixed or real. Ellis makes a similar point, arguing that physicists who think the future is already laid out “are not taking quantum uncertainty seriously” (1). Quantum uncertainty implies that the future is not determined until it happens — until those potential outcomes collapse into one actual outcome (1). Thus, modern physics — when taking both relativity and quantum mechanics into account — offers strong hints that the future does not exist in the same manner as the present. It is a set of possibilities, not an actual part of the world yet. We have records and evidence of the past, and we experience the present, but we have no direct evidence of the future because, as far as physics can tell, the future has not happened (and therefore does not exist) until it becomes the present.

Neuroscience: The Brain as a Time Machine

While physics deals with external reality, neuroscience looks at how we internally experience time. Interestingly, our brains seem to treat the future very differently from the present or past. We live continuously in the present moment, and we can recall the past through memories — but how do we “experience” the future? The answer is: we don’t experience the future directly at all. Instead, we imagine or simulate it. From the brain’s perspective, the future exists only as a mental construction. Neuroscience research shows that the same neural machinery used for memory is also used for future imagination. The hippocampus, a brain region essential for forming new memories, is equally crucial for envisioning possible future events. Patients with damage to the hippocampus (such as the famous amnesic patient H.M.) not only struggle to remember past events but also cannot imagine themselves in new situations or plan for the future (3). In one study, individuals with hippocampal damage were asked to imagine a simple future scenario (like lying on a beach); they produced only fragmented, incoherent images, suggesting an inability to construct a future scene (3). By contrast, people with healthy brains activate the hippocampus even more when imagining future events than when recalling past ones (3). This overlap in brain activity strongly indicates that the future we “see” in our mind’s eye is generated by the memory system, recombining bits of past experience to create a novel scenario.

Why would memory and imagination be so intertwined? Neuroscientists propose that memory’s evolutionary purpose is precisely to allow us to project ourselves forward in time. We remember the past so that we can anticipate the future. As one researcher put it, “from an evolutionary perspective, we are reasonably sure that the purpose of memories is actually in the future. Memories allow you to take experiences that you have and retrieve them to make predictions about what will happen next” (3). In other words, remembering is not just for reminiscing — it’s for future survival. Your brain constantly uses past information to simulate upcoming possibilities (Where might I find food? How should I navigate this social situation? What if I take this action?). These simulations happen on many timescales: we plan for events years ahead, but we also continuously predict what will happen seconds or milliseconds from now (allowing us, for example, to catch a ball or finish someone’s sentence). All of this is internally generated. The brain is essentially a time machine — but one that only travels in a virtual sense. It can revisit the past (via memory) and pre-live the future (via imagination), yet we are always physically stuck in the present.

Modern cognitive neuroscience has formalized this idea through concepts like “mental time travel” and predictive processing. Mental time travel refers to our capacity to mentally project ourselves backward or forward in time, recalling past episodes and imagining future ones. This ability appears to be uniquely developed in humans and is deeply dependent on brain networks centered on the hippocampus and related areas. Studies have found that when rats run a maze, their hippocampal neurons fire in sequences that represent possible future paths the rat might take, effectively letting the animal “try out” different futures before choosing a direction (3). Similarly, in humans, when we navigate our lives, our brains may rapidly flip through multiple hypothetical scenarios (for example, envisioning different outcomes of a conversation) without our conscious awareness, as a way of guiding decisions (3). Such neural evidence reinforces that the future we anticipate is being actively generated inside our heads. It is not something we perceive or detect externally; it’s constructed from within. As one neuroscientist remarked about these findings, “our imaginings are coming from ourselves, and they are not from this external reality” (3). In short, the brain distinguishes between reality and imagination: it knows the difference between what is actually happening now and what is a self-generated possibility.

Crucially, imagined future experiences are recognized by the brain as unreal while we imagine them. We can think about tomorrow’s meeting or a vacation next summer, but as we do so, we (normally) understand this is just a thought, not an actual event occurring in the present world. A recent scientific review summarized this point: imagined experiences “do not refer to actual present experience, or directly reflect ongoing circumstances in the external world. Rather, imagined experiences refer to non-actualities, and arise from a source internal to the subject” (4). In other words, the future exists in our mind as a “non-actual” scenario generated by internal brain processes. The neurological evidence thus strongly supports the idea that the future has no independent reality — biologically, it’s a story the brain tells using memories and creativity. It is striking that every time we talk about the future, we are essentially engaging in an act of imagination. Even our most rigorous scientific predictions or personal plans are, at the neural level, hypothetical simulations constructed by our brain’s default mode network and memory systems. The only time we truly experience is the present; everything else is either remembered or imagined.

Philosophy: Presentism, Possibility, and the Reality of the Future

Philosophers have long debated the ontology of time — that is, what times (past, present, future) are real. One school of thought known as presentism holds that only present objects and events exist, strictly speaking; the past has existed but is not existent now, and the future does not exist at all (except as an idea) (5). In the words of St. Augustine, “the time present of things past is memory; the time present of things present is direct experience; [and] the time present of things future is expectation” (6). Augustine’s insight, from the 4th century, elegantly captures the notion that the past and future have their being only in the present moment — the past persists in our minds as memory, and the future lives in our minds as expectation. Outside of this, the past is no longer real and the future is not yet real. Modern presentist philosophers echo this idea in more analytic terms: the future will come to be, but is not now part of reality (5). Reality, on this view, is like a spotlight moving through time: only what it currently illuminates (the present) exists, while past events have faded out (though we retain records) and future events lie in darkness awaiting their turn.

A closely related view in the philosophy of time is called possibilism or the growing block theory. Possibilism agrees that the future is not real in the way the present is. It posits that the past and present exist (forming a “block” of reality that grows with time), but the future does not yet exist (5). You can visualize this as a tree growing upwards: the trunk and branches so far are the past and present — solid and real — but at the tip, new growth is constantly adding ring by ring. The future consists of the as-yet unformed leaves and branches. In the growing block view, only possibilities inhabit the future. Philosophers describe the future here as a “branching structure of alternative possibilities” emanating from the present (5). Each moment, one of those possibilities becomes actual (grows into the trunk as a new segment of reality), while the other possible futures fall away. This imagery highlights that, until an event actually occurs, it is not an existent fact but merely one potential outcome among many. The implication is clear: the future has no ontological status (no real being) apart from these possibilities.

This philosophical stance is deeply intuitive and aligns with how we observe the world. We find that we can know a lot about the past — history is recorded in books, fossils, photographs, and memories — but we cannot know the future with the same certainty. The asymmetry between past and future in terms of knowledge and causation is a classic argument for the unreality of the future. As one analysis notes, we can easily ascertain yesterday’s events (for example, the closing price of a stock), but no amount of effort can ascertain tomorrow’s events today (5). If the future already existed in the same way the past does, one might expect it to leave some trace or be knowable in advance, but it isn’t. Likewise, we feel that we can influence the future (through our choices and actions), whereas we are powerless to change the past. This is because the future is open — it is a realm of possibilities that our present actions help shape — whereas the past is fixed and closed off. “My future actions can actualize some future possibilities as opposed to others, whereas past actions… no longer admit of alternatives” as the Stanford Encyclopedia of Philosophy explains (5). These asymmetries make sense if only the present (and possibly the accumulated past) exist: the future isn’t set, so we have freedom to mold it, and until it happens there is nothing concrete to perceive or know. By contrast, if one believed the future were already out there, predetermined, it would be hard to explain why we have no access to it and why our deliberations feel meaningful. Most philosophers therefore treat the future as ontologically different from the present. It exists in a conceptual sense (we can talk about “the year 2100” or “tomorrow’s weather”), but not in an actual sense.

It’s worth noting that not all philosophers agree — the opposing view is eternalism, which is akin to the physicists’ block universe idea that past, present, and future are equally real. Eternalists argue that saying an event is future is like saying a place is “far away” — it doesn’t make it less real, just not here/now. However, eternalism comes with difficult consequences, such as the apparent paradox of a “fixed” future and the question of why we subjectively experience a flow of time at all. The presentist or possibilist view avoids these issues by asserting that the flow of time is the process of reality coming into being. The future’s non-existence is not a flaw but a feature: it is what allows change, novelty, and free will. As one philosopher put it, possibilism “captures much of the way we think about time” because it reflects these deep intuitions about knowing the past but not the future, and about the openness of what is yet to come (5).

In summary, the philosophical perspective provides a conceptual framework supporting the idea that the future is nothing more than a useful notion. The future is a place-holder for possibilities — a word we give to the collection of events that might occur, not a realm of actual things waiting for us. Whether through Augustine’s introspective analysis of time or contemporary metaphysics of time, the message is the same: the future does not exist except in our minds. We project ourselves forward with expectations and plans, but until those plans become present realities, they are ideas, not facts.

Conclusion

Across physics, neuroscience, and philosophy, we find converging support for the thesis that the future is not an independently existing entity, but rather a projection created by the human mind. Physics suggests that while the laws of nature allow us to predict many things, the future remains fundamentally probabilistic and undefined until it unfolds. Even in a relativistic universe, one can interpret time in a way that only the “now” is real and the future is genuinely not yet there (1). Neuroscience reveals that our sense of the future comes entirely from within: the brain uses memory and imagination to construct possible scenarios, essentially inventing the future as a mental exercise so that we can prepare for it (4) (3). And philosophy provides a language to articulate why it makes sense to treat the future as just a concept or potential rather than an actuality (5).

Embracing the idea that “only the past and present exist” has profound implications. It reminds us that the future is open — a sandbox of possibilities rather than a fixed destiny. What we call “the future” is, at this moment, a set of ideas, hopes, fears, and predictions in our heads. Far from rendering the future unimportant, this realization can be empowering: since the future is not pre-existing, it is ours to create. It also has a humbling effect, because it means no one can ever be completely certain about what hasn’t happened yet. Our plans and expectations are provisional, subject to change when reality catches up. In a very real sense, we continuously participate in bringing the future into existence as each moment arrives. Science and philosophy together affirm that the flow of time is a creative process, turning today’s imaginings into tomorrow’s reality. Thus, the future as we conceive it truly is a human invention — a necessary fiction that guides us, but one that remains unreal until the present makes it real. By understanding this, we appreciate why we must use the tools of memory, reason, and imagination to navigate an unwritten tomorrow, and why ultimately the only time that truly exists is now.

Sources:

1. Ellis, G. F. R. (2018). On the flow of time in the universe. Discover Magazine. (Discusses the evolving block universe and why the future is not yet real) (Is the Future Already Written? | Discover Magazine).
2. Hawking, S. & Mlodinow, L. (2010). The Grand Design. Bantam Books. (Noted that quantum physics implies the future exists only as a spectrum of possibilities) (Quote by Stephen Hawking: “Quantum physics tells us that no matter how tho…”).
3. Wickelgren, I. (2023). Where Imagination Lives in Your Brain. Scientific American. (Reports that the hippocampus is critical for imagining future events, indicating the future is constructed by the brain) (Where Imagination Lives in Your Brain | Scientific American) .
4. Comrie, A. E., et al. (2022). Imagination as a fundamental function of the hippocampus. Phil. Trans. R. Soc. B, 377(1853):20210336. (Scientific review concluding that the hippocampus generates hypothetical scenarios, i.e. imagined futures) (Imagination as a fundamental function of the hippocampus | Philosophical Transactions of the Royal Society B: Biological Sciences).
5. Stanford Encyclopedia of Philosophy. Time. (Especially sections on Presentism and Possibilism, explaining that in these views the future is not actual but only possible) ( Being and Becoming in Modern Physics (Stanford Encyclopedia of Philosophy) ).
6. Augustine of Hippo (circa 400 AD). Confessions Book 11. (Philosophical reflection that the future exists only as expectation in the mind) (The time present of things past is memory; the time present of things present is direct experience; the time present of … — Augustine of Hippo — Confessions).