It is what it is. What even is, is?

We say “it is what it is” when further argument seems unlikely to improve a situation. Usually this is sensible. A missed train does not return because we reconsider the nature of time. Taken more literally than anyone usually intends, though, the phrase leaves me wondering how much we know about the thing we are being asked to accept.

In a dream, that assurance can be almost complete. There is somewhere to stand, something to do and a reason it matters. We may be trying to reach a place, escape a threat or take a single step that refuses to happen. The task does not wait for us to establish the existence of the world in which it occurs. We are already involved.

I have had dreams that seemed irrelevant when I woke, and others that permanently altered my waking life. Some were ordinary; others were vivid lucid nightmares. The differences matter because “only a dream” can dismiss several different things at once. It can mean that the dream gives us no reliable account of an external event, that the experience had no significance, or that its consequences should have ended when I opened my eyes. Discovering that I was dreaming gives me a reason to question the account; it does not settle the significance or erase the consequences.

The experience occurred. Fear was felt, even if there was no external threat corresponding to it. A person can wake relieved and still carry something from what happened. This gives us at least two questions whenever we ask whether a dream was real: did the experience take place, and did the world it presented exist in the way it appeared? Answering one does not automatically answer the other.

The capacity to present a world is itself remarkable. A games console needs hardware and software to produce a scene that we can move through. It has rules for motion, surfaces and what happens when objects meet. Dreams can present some of the same apparent regularities, together with a body that seems to belong to us. We can feel the effort of moving or the alarm of falling without needing to formulate any rules.

The comparison invites a mistake, though. Feeling that one is falling does not require a new gravitational field inside the dream, any more than imagining a heavy object requires an object with mass inside the skull. Nor must a dream calculate an entire environment in the manner of a game engine. What appears is an experience of a world, sometimes incomplete, unstable or impossible. Its convincingness tells us something about the experience; it does not tell us how much of a world has been constructed behind it.

Dreaming therefore makes an ordinary assumption more difficult to maintain. A scene can feel present without being a perception of events currently occurring around the sleeping body. The sense that “I am here, and this is happening” cannot by itself guarantee the account we give of what is happening. We discover this after waking, when the dream becomes available for comparison with a more continuous history.

That comparison gives waking life a substantial advantage. We return to places, encounter consequences that persist, compare observations with other people and find that wishing seldom changes what a measurement reports. Evidence about sleep also connects changes in brain activity with the experiences later reported as dreams. These relationships provide reasons to distinguish dreaming from waking. The distinction rests on more than the intensity with which either state persuades us while we occupy it.

Yet we still make these judgements from somewhere within experience. This is where the more speculative question begins. Could waking life stand in a relation to some further reality resembling the relation a dream bears to the sleeping person? The possibility is difficult to exclude merely by pointing out that the present world feels convincing. Dreams have already shown why that particular assurance is insufficient.

A dream within a dream can make the question especially compelling. One seems to fall asleep, enter another scene and then wake into the earlier one, perhaps still unaware of dreaming. But a body represented in the first dream need not have produced the second. The sequence may belong to one continuing dream experience. The appearance of several levels does not establish several independent hosts, any more than a dream about a television establishes a second device transmitting the pictures.

The analogy can loosen our confidence that the standpoint we presently occupy must disclose everything about its own conditions. It cannot tell us that another level exists, who or what inhabits it, or whether we would survive the end of this one. Those would require reasons beyond the fact that dreams can feel real. A possibility remains available for thought without becoming the most likely explanation.

There is a temptation to make that possibility consoling. Perhaps death is a waking, perhaps the effort here becomes a memory elsewhere, perhaps something larger learns through us. I can understand the appeal. It gives this life's seriousness a surrounding context in which even loss might be carried forward. But the comfort an account offers cannot decide whether there is anyone outside this life to receive its lessons.

We can ask what the possibility changes while it remains uncertain. A dream's lack of an external counterpart does not erase the fear felt within it. Likewise, imagining a further level of reality gives us no reason to become careless with suffering here. People remain vulnerable to what we do, and the consequences we can observe remain the consequences for which we can answer. Metaphysical uncertainty does not suspend those relationships.

Perhaps the most useful thing dreams offer this question is a distinction we ordinarily pass over. Being certain that an experience is happening differs from being certain that we understand what makes it possible. We can take the first seriously while continuing to examine the second. “It is what it is” may still be a reasonable response to the missed train. It is a less complete answer to the world in which we missed it.

Further reading: Siclari and colleagues: the neural correlates of dreaming.