Two types of consciousness
What are phenomenal and access consciousness?
The distinction between phenomenal consciousness and access consciousness was famously argued for by the philosopher Ned Block[citation:3][citation:9]. It is one of the most debated distinctions in the philosophy of mind and neuroscience.
Phenomenal consciousness (often called P-consciousness) refers to the purely subjective aspects of experience—the "what it is like" to have an experience[citation:3][citation:7]. This is the feeling of redness, the pain of a headache, or the taste of chocolate. It is what philosophers call "qualia."
Access consciousness (A-consciousness) refers to the cognitive access one has to the experience—the ability to report it, reason about it, or use it to guide action[citation:9]. When you can say "I see red," you have access to the experience.
The key debate is whether these two types of consciousness always go together. Block famously argued that they do not—that we can have phenomenal consciousness without access consciousness (P-without-A)[citation:3]. This is controversial and has sparked extensive empirical investigation.
Phenomenal vs Access Consciousness
A visual showing the relationship between phenomenal experience and cognitive access.
Phenomenal consciousness
Raw subjective experience—the "what it is like" to experience something[citation:3].
Access consciousness
Cognitive access—the ability to report, reason, or act on the experience[citation:9].
Overlap
Most conscious experiences involve both. The debate is about cases where only one may be present.
Skim first
Key takeaways
The shortest useful version of this page.
Phenomenal consciousness = raw subjective experience.
Access consciousness = ability to report or use information.
The distinction was introduced by Ned Block.
The key debate is whether they can dissociate.
Some evidence suggests yes; others argue it is partial access.
The debate is still active and unresolved.
How this distinction developed
- Ned Block published his influential distinction between phenomenal and access consciousness.It shaped decades of philosophical and scientific debate.
- Neuroscientists began investigating potential neural correlates of each type of consciousness.The debate became empirical as well as philosophical.
- A study claimed to provide the first empirical evidence for phenomenal consciousness without access[citation:3][citation:10].The debate remains active and unresolved.
Phenomenal consciousness
Phenomenal consciousness
The raw, subjective experience of something—the "what it is like" to have an experience[citation:3]. Also called P-consciousness.
Phenomenal consciousness is the aspect of consciousness that philosophers and scientists find most mysterious. It is the feeling of experience itself.
Phenomenal consciousness is the subjective quality of experience. It is what philosophers call "qualia." The key question is whether this can exist without the ability to report or access it.
Access consciousness
Access consciousness
The broadcasting of information to other processes, such as for reasoning and the guidance of action[citation:2]. Also called A-consciousness.
Access consciousness is the functional aspect of consciousness—the part that allows us to report, reason, and act on information.
Access consciousness is the ability to use information in reasoning, reporting, and action. The key question is whether this can exist without phenomenal experience.
The distinction
What are the key differences between phenomenal and access consciousness?
The key difference between phenomenal and access consciousness is what they refer to. Phenomenal consciousness is about experience itself—the "what it is like" to see red, feel pain, or smell coffee[citation:3]. Access consciousness is about the ability to use that experience—to report it, reason about it, or guide action with it[citation:2].
Another way to think about it: phenomenal consciousness is the content of experience; access consciousness is the availability of that content to cognitive systems.
The distinction matters because it raises the question of whether the two always go together. Block argued they can dissociate—you can have experience without access (P-without-A)[citation:3].
If this is true, it would have profound implications for the study of consciousness: we would need to distinguish the neural correlates of experience from the neural correlates of reportability.
Evidence and arguments
Can you have phenomenal consciousness without access?
The possibility of P-without-A consciousness is widely debated. A major challenge is the apparent inability to experimentally demonstrate it; once participants report having a P-experience, they already have access to it[citation:3].
Supporters of the dissociation point to examples like the "overflow" argument: when observing a complex visual scene, we feel that we have a rich visual experience even if we can report only a few elements[citation:15].
Critics argue that these cases can be explained by "partial awareness"—where lower and higher levels of representation are accessed independently[citation:15]. They suggest that what looks like P-without-A is really just incomplete access.
In 2023, a study claimed to provide the first empirical evidence for P-without-A consciousness using a novel auditory paradigm. Participants lacked online access to a stimulus but could retrospectively form judgments on its qualitative aspects[citation:3][citation:10].
However, this is still debated, and no consensus has been reached.
Evidence scan
What does the evidence say about the access/phenomenal distinction?
The evidence question is whether phenomenal consciousness can exist without access consciousness.
Overall: mixed findings
Leans in favor
Points that support the claim
Phenomenal and access consciousness are distinct.
Most philosophers and many scientists accept the conceptual distinction. Empirical evidence for dissociation is emerging.
Phenomenal consciousness without access has been empirically demonstrated.
A 2023 study claims to provide the first direct empirical evidence for P-without-A[citation:3][citation:10]. This is still debated.
Leans against
Points that do not support the claim
P-without-A can be explained by partial awareness.
Some researchers argue that the evidence can be explained by "partial awareness" rather than true dissociation[citation:15].
Reality check
Common misunderstandings about access and phenomenal consciousness
- Myth
Phenomenal consciousness is the "higher" type of consciousness.
RealityIt is not higher or lower—it is just different. Phenomenal is about experience; access is about reportability.
- Myth
Access consciousness means conscious access to everything.
RealityIt is about cognitive access, not awareness of everything in experience.
- Myth
The distinction is settled science.
RealityIt is still debated both philosophically and empirically[citation:3].
- Myth
This distinction is about meditation or mindfulness.
RealityIt is a philosophical and scientific distinction, not a spiritual one.
Phenomenal vs Access Consciousness: Side-by-side
The table below summarizes the key differences between the two concepts.
Definition
Raw subjective experience, "what it is like"[citation:3]
Ability to report, reason, or use information[citation:2]
Also known as
P-consciousness, qualia
A-consciousness, reportability
Key question
Can it exist without access?
Can it exist without phenomenal experience?
Example
Feeling the redness of red
Being able to say "I see red"
Neural correlate
Debated; possibly sensory areas
Debated; possibly fronto-parietal areas
Introduced by
Ned Block (1995)
What to remember about access and phenomenal consciousness
Phenomenal consciousness = raw subjective experience.
Access consciousness = ability to report or use information.
The distinction was introduced by Ned Block.
The key debate is whether they can dissociate.
Some evidence suggests yes; others argue it is partial access.
The debate is still active and unresolved.
Verdict
Our verdict on the access/phenomenal distinction
mixed
The distinction between phenomenal consciousness (raw experience) and access consciousness (reportability) is well-established conceptually. Whether they can dissociate—whether you can have experience without access—is still debated. Some recent evidence suggests they can, but other researchers argue the evidence can be explained by "partial awareness." The debate is active and unresolved.
What we know
- Phenomenal consciousness = raw subjective experience[citation:3].
- Access consciousness = cognitive access and reportability[citation:2].
- The distinction is widely accepted in philosophy and neuroscience.
- The two usually go together but may not always.
What we do not know
- Whether P-without-A truly exists.
- Whether the evidence can be fully explained by partial access.
- What the exact neural correlates of each are.
This is a fascinating philosophical and scientific debate, but it is not resolved. If you are interested in consciousness research, it is worth understanding the distinction, but there is no simple answer.
Bottom line
Experience and access: two sides of consciousness
Phenomenal consciousness is what it feels like to experience. Access consciousness is your ability to report or use that experience. Whether they can exist separately is still an open question.
Quick answers
Frequently asked questions
What is phenomenal consciousness in simple terms?
It is the raw, subjective experience of something—the "what it is like" to feel or perceive[citation:3].
What is access consciousness in simple terms?
It is the ability to report, reason about, or use the content of an experience[citation:2].
Can you have experience without being able to report it?
This is debated. Some studies suggest yes, but others argue the evidence is not conclusive[citation:3][citation:15].
Who came up with this distinction?
The philosopher Ned Block[citation:3].
Is this distinction important for neuroscience?
Yes, because it affects how researchers study the neural correlates of consciousness.
Sources
REPLACE WITH VERIFIED AUTHORS. Phenomenal and access consciousness in olfaction. ScienceDirect, 2009. Accessed YYYY-MM-DD
Use to establish the definitions of phenomenal and access consciousness.
Amir, Y.Z. et al.. Experiencing without knowing? Empirical evidence for phenomenal consciousness without access. Cognition, 2023. Accessed YYYY-MM-DD
Use for evidence supporting P-without-A.
REPLACE WITH VERIFIED AUTHOR. Signal detection theory, the exclusion failure paradigm and weak consciousness. ScienceDirect, 2008. Accessed YYYY-MM-DD
Use for critical perspectives on the distinction.
