How do you know you're conscious?

People use words every day that they don't understand. So, what do they mean when they use them? Nobody knows. For most, language is a system of simulating connection, but commonly, there is no real communication going on. In these instances, words become vague signifiers, perhaps representing some nebulous subjective experience, or just fulfilling the expectations of a specific social context; the hollow pretence of meaning where none exists. Consciousness is a typical example. A word people deploy without having the slightest clue what it means, they just assume they do. If you point out they don't, they think you're trying to be 'too clever' or you have some sort of superiority complex. However, the opposite is true. Thinking you know everything without exploring, reading, and researching, is grandiose arrogance.

Science is the method we use to confirm patterns observed in 'reality', and therefore a means of bringing some objectivity to subjective interpretation. This helps humans communicate, as there is a defined point of reference for the terms, concepts, and patterns used. However, science is corruptible, fallible, and cannot answer many questions. In truth, we'll never have scientific knowledge of fundamental issues, such as the cause of existence, and a complete scientific knowledge of how all things interact is impossible. At best, we can gain some explanatory capacity of an extremely small proportion of our experience, and the workings that give rise to them. The rest is effectively 'magic'. Magic in the sense that we can experience things, including patterns and connections, that we cannot understand scientifically. It's not that they're not capable of causal analysis. Given infinite resources and eternity to conduct investigations, we could probably understand them, but that won't happen, so we'll never know them in this way. As good as theoretical models are, and computer modelling can be, neither are true science; that must be performed experimentally. This limitation doesn't prevent us from non-scientific discussion, conceptualization, or activity, but we need to acknowledge the subjectivity and uncertainty of such things, otherwise our communication, and the activities arising from it, can be damaging.

Beyond science, other ways of knowing are common. One category might be labelled common sense, but that implies a claim to authority that common sense often lacks. Common ways of behaviour and thought are often grossly mistaken, resulting in appalling outcomes. Still, frameworks of cultural knowledge can be useful for navigating the world, and intuition, when honoured, questioned, and honed, can be our most valuable resource. A world-class footballer in the flow of the game is not using science, but intuition built on practice (ritual), experience, and reflection.

Consciousness is typical of how damaging 'common sense' opinion can be. The debate about AI, consciousness, free will, and what it means to be human, has brought philosophy to the kitchen table. However, most people are poorly equipped for it; experts too. There's genuine fear involved in discovering that something you thought you knew about yourself, something absolutely fundamental, is something you don't understand and have never really contemplated. Worse still, science doesn't have the answer either. The reasonable thing to do in such circumstances is accept your limited knowledge, and be cautious when deploying the concept, especially when making judgments about things that could have profound effects. But life is not a reasonable thing, and the pattern of evolution is a random process that some beings survive long enough to make replicas of themselves, it's not a rational process. So, humans are not well equipped to be reasonable, but to be effective, even if that means ignorance, violence, and injustice.

In science, consciousness is often described as subjective experience; there being 'something' it is like for an organism to perceive, feel, or think. This generic definition is neutral across theories, but must be operationalized for science. In other words, it is useless as is. For scientific investigation, the concept of 'consciousness' is reconstructed, typically by distinguishing global states, such as wakefulness and arousal, from more specific phenomena, such as what is experienced, and by triangulating first-person reports with behaviour and neural measures. This is problematic. Definitions vary, shaped by the different theories being tested. In other words, science doesn't know what consciousness is, but it hopes to find out through informed, speculative exploration.

Examples of theories of consciousness

Global Neuronal Workspace (GNW): this identifies a process called ignition, where long-range neurons (those that broadcast signals globally across the brain), communicate select information derived from localized, unconscious processes, in order to give rise to an integrated experience that can be used for higher-level functions (such as planning and decision-making). The term 'Global Workspace' is used to refer to the synthesized experience of multiple funnels of input; the prefrontal cortex acting as a hub.

Integrated Information Theory (IIT): identifies consciousness with the system’s capacity for integrated and differentiated information. In essence, this is very similar to GNW. Stuff comes together from unconscious processes, forming a separate synthesized phenomenon. One of the main differences is that IIT considers the posterior cerebral cortex to be the main area where consciousness arises.

Recurrent Processing Theory (RPT) emphasizes recurrent sensory-cortical interactions as sufficient for phenomenology (the subjective experience of things). The explanation suggested here is that the initial information processed by the brain passed through another 'higher' area of the brain which then represents the information to the originator, and this is where the conscious experience arises. It is confusing because it involves a 'higher' brain area, but is not a higher-order theory (see next) because the place where awareness arises is the originating localized process.

Higher-Order Theories (HOT): identify consciousness with a metacognitive state. So, the brain can process numerous things, but only those presented to this meta process are those we become aware of. Higher-order theories are usually distinguished from both GNW and IIT which equate the awareness with the process itself, rather than the process transmitting information to a different process which gives rise to awareness.

As you can see, the word “consciousness” is problematic. Not only do we have no consistent evidence for it's existence, but there is no agreed definition of what it is, and measuring subjective qualia is simply impossible, and always will be. Because the term consciousness is so broad, and used heterogeneously, it leads to measurement confounds, and theory-dependent interpretations. If a single word has multiple interpretations, requiring differing and incompatible factors to define it, not all of which are measurable or proven to exist, what does the word really mean?

Conflation, Context, and Confusion

Another issue with the word 'consciousness' is how it's often used interchangeably with other related concepts. For example, wakefulness is the state of not being asleep, but being awake has a spectrum of mental states, including sleep paralysis (aware, but immobile and prone to hallucinations). Arousal is a concept relating to the level of alertness an individual body has, that is, how responsive and energetic they are. However, arousal can occur without awareness, especially relating to cues that stimulate the autonomic nervous system. Having subjective experiences is generally considered to be the most fundamental indicator of awareness; dreaming, and lucid dreaming, are forms of awareness that occur while asleep. Such awareness in sleep is often called dream consciousness. So, being asleep is not synonymous with being unconscious. Attention is another way of describing a mental state relating to focus, but it isn't the same as arousal, awareness, or wakefulness. More detailed consideration of consciousness, and mental states, might include concepts such as metacognition and self-reflection. They are related but separable. HOT links them tightly, but other frameworks allow phenomenology without explicit self-representation. Sentience is the capacity for experiences, often used in cross-species contexts, and depends on operational criteria. A sentient being can experience pain, pleasure, and other subjective states, but may lack aspects associated with consciousness such as self-awareness and intentionality. It is generally assumed that for a being to be sentient, it must be conscious. However, not all consciousness is considered sentient. Consciousness can also be present without sentience. That is, without the capacity to experience sensory input from outside the location of the conscious experience.

Using a word, and understanding its meaning, are not the same thing. It's a common mistake that people make. In everyday usage, words such as consciousness, sleep, awareness, attention, and arousal, are frequently conflated. They may function as rough indicators in general conversation, but this doesn't equate to a precise understanding of the meaning or concepts signified by the words. Even within scientific settings, terms may be confused, conflated, or misidentified. All of this makes communication innaccurate, and the expression of inner, subjective states uncertain.

Scientists study consciousness using several experimental approaches, each highlighting a different aspect of how conscious experience might arise. These include:

• Relying on people’s reports — for example, asking whether they saw something, how clearly they saw it, or how confident they are. These approaches align with theories like the Global Neuronal Workspace and Higher-Order Thought (GNW & HOT), which emphasize reportability.
• Other approaches try to avoid relying on reports altogether. They infer what someone is experiencing from eye movements, pupil changes, or other physiological signals. The goal is to reduce the influence of reporting itself and get closer to the neural activity tied to raw experience.
• Contrastive methods compare brain responses when a stimulus is consciously perceived versus when the same stimulus is not — such as during visual masking or binocular rivalry.
• State-based methods examine how consciousness changes across conditions like sleep or anesthesia, where the level of consciousness naturally varies.
• Quantitative neural measures, such as the Perturbational Complexity Index (PCI) derived from TMS–EEG, try to capture how integrated and complex brain activity is. These values may reflect the brain’s overall capacity for consciousness.
• Finally, network-level markers look at communication across brain regions, especially long-range cortical and thalamo‑cortical connections that are thought to support conscious experience.

Experimental findings on consciousness point to several key conclusions:

• First, relying on people’s reports can be misleading. Some late brain signals — like the P3b wave or certain prefrontal activations — often reflect attention, task relevance, or the act of reporting rather than awareness itself. This has motivated the use of no‑report methods, which help reveal that the clearest neural correlates of conscious experience tend to appear in posterior sensory regions rather than in the frontal cortex.
• Second, studies of anesthesia and sleep show that changes in consciousness go hand‑in‑hand with systematic, reversible changes in brain dynamics. General anesthetics and deep non‑REM sleep reduce long‑range communication in the brain and alter interactions between the thalamus and cortex. These findings distinguish unconscious states from 'disconnected' conscious states like dreaming, and from fully 'connected' waking consciousness. Because these states can be manipulated, they provide causal evidence that the brain’s integration and overall network structure are crucial for maintaining consciousness.
• Third, complexity‑based measures such as the Perturbational Complexity Index (PCI), obtained by zapping the brain with TMS and measuring the EEG response, reliably differentiate levels of consciousness across sleep, anesthesia, and clinical disorders. They do so even when no behavioral report is possible, suggesting that the brain’s capacity for richly integrated and differentiated activity is a useful, practical indicator of consciousness.

Theories of consciousness are being tested against these findings:

• The Global Neuronal Workspace theory has strong behavioral and neural support for its claims about flexible access, but its predictions must be disentangled from the effects of reporting.
• Integrated Information Theory gains indirect support from complexity and integration measures and from evidence pointing to a posterior hot zone as central to conscious experience.
• Higher‑Order Thought theory is supported by metacognitive and prefrontal signals in report‑based tasks, but struggles to explain no‑report findings.
• Recurrent Processing Theory aligns well with results from masking, binocular rivalry, and early recurrent activity in posterior sensory areas.

Overall, reviews stress that these approaches are complementary. Progress will require direct comparisons between theories and better alignment between theoretical claims and the experimental measures used to test them.

It's claimed that the current body of evidence supports consciousness as a scientific construct. Despite conceptual disputes, converging paradigms demonstrate reliable behavioral–neural regularities tied to reported subjective experience, and its loss or alteration. The problem is that they do not, and cannot, confirm the subject is having any experience at all, only that they are reporting one. By virtue of the fact that subjective inner experience is scientifically inaccessible, it can never be proven using the scientific method. The strongest argument is for consistent correlation between measurable factors and reported factors. This point is far more important than researchers generally admit. In fact, it exposes the circularity of the theory about consciousness. Namely, that the construct was created and imagined before being investigated, and investigations are aimed at evidencing the construct, not questioning it. In other words, it is assumed to exist because people say it does. There is an inherent bias in this line of thinking, and lack of critical deconstruction about the idea itself. Of course, if you were explicit about consciousness being scientifically unfeasible to prove, it might poke a hole in the human superiority complex, and make funding more difficult to obtain.

References

Boly, M., Seth, A. K., Wilke, M., Ingmundson, P., Baars, B., Laureys, S., ... & Tsuchiya, N. (2013). Consciousness in humans and non-human animals: recent advances and future directions. Frontiers in psychology, 4, 625.

Dembski, C. (2020). Assessing Consciousness Theory: A Systematic Scoping Review of 25 Years of Empirical Evidence for Neuroscientific Theories of Consciousness.

Dennett, D.C., 2016. Illusionism as the obvious default theory of consciousness. Journal of Consciousness Studies, 23(11-12), pp.65-72.

Kapantaidakis, V. (2025). Theories of Consciousness A Biological Roadmap for Studying Consciousness (Doctoral dissertation).

Sattin, D., Magnani, F. G., Bartesaghi, L., Caputo, M., Fittipaldo, A. V., Cacciatore, M., ... & Leonardi, M. (2021). Theoretical models of consciousness: a scoping review. Brain sciences, 11(5), 535.

Tsuchiya, N., Wilke, M., Frässle, S., & Lamme, V. A. (2015). No-report paradigms: extracting the true neural correlates of consciousness. Trends in cognitive sciences, 19(12), 757-770.