A 90-year-old will have spent around 32 years of his life sleeping. What a ludicrously immense investment of time for an activity that we don’t even understand.

Yes, there are various ideas (energy conservation theory, restorative theory, brain plasticity theory) about this most common of human necessities, but there are no obvious answers. It’s one thing to need to rest – to stop moving for a while and recharge – but of what purpose is an entirely altered state of consciousness?

I’ve always loathed the necessity of sleep. Like death, it puts even the most powerful men on their backs. Frank Underwood, House of Cards

Evolutionarily speaking, sleep seems rather dangerous. Why would natural selection have selected a regenerative mechanism that renders us all unconscious (and thus easy targets) for a third of our lives? It could have all been done much more effectively! In fact, there are multiple examples of smarter sleep mechanisms in the animal kingdom.

Dolphins, for instance, accomplish something called unihemispheric sleep: only half their brain sleeps, while the other half ensures the dolphin stays close to the surface to breathe and on guard for predators. They alternate between the two hemispheres to get sufficient sleep for their whole brain. Now that’s efficient!

Ostriches and Platypi sleep standing up with both eyes open.

Bullfrogs don't even go into a sleep state. Instead, they go into simple states of rest throughout the day.

Altered States of Consciousness

The ways to enter into an altered state of consciousness are myriad and well-documented and include, among others, hallucination, hypnosis, trance states, meditation and psychotropic substances (including, but not limited to, drugs and alcohol). For the most part, people have actively sought out experiences, through media (music, seance), substances and/or transcendental experience. It’s apparently a primal desire to take leave of one’s normative senses: cultures have pursued such experiences for as long as culture has existed.

Pre-Columbian Maya society, for instance, ritually consumed balché, a mead-like drink made with the hallucinogenic plant Longocarpus longistylus. The Olmec used hallucinogens such as native tobacco (Nicotiana rustica) or the psychoactive venom found in the parathyroid gland of the marine toad Bufus marinus.

But why? Was it all just for kicks, or was there something a lot deeper at play?

When we all fall asleep, where do we go? Billie Eilish

Sleep may be the only altered state we enter into involuntarily. There are several stages in the sleep cycle. Each is fairly complex. In Stage 2 a person begins to experience sleep spindles, K-complexes, Theta, and Delta waves. These are all waves that can be identified via electroencephalogram. During this stage (and much like other trance states), our heart rate and breathing slow and our body temperature decreases.

That’s all fine and good but let’s ask once again, why? Why would we prefer Theta waves to our normative consciousness? Why not stay alert and productive like the amazing bullfrog? What’s going on?

Two Kinds of Consciousness

How it is that a material thing (like a human) can possibly have achieved awareness of itself is yet another grand mystery for which we have no definitive answer. Science and philosophy have been kicking this one around for hundreds of years. Something important happened in the late 19th century when Freud and others popularized our understanding of the layer of awareness we now refer to as the subconscious or unconscious mind. How odd it must have been to come to the realization that much of what we are thinking at any given time — about the world, about yourself, about anything — is something of which you are functionally unaware.

What is the origin of these two levels of consciousness?

For indeed our consciousness does not create itself. It wells up from unknown depths. In childhood it awakens gradually and all through life it wakes each morning out of the depths of sleep from an unconscious condition. It is like a child that is born daily out of the primordial womb of the unconscious. Carl Jung

For those who are familiar with the morning meditations of the Siddur (the Jewish book of prayer), Jung’s words will sound familiar:

My God the soul which You bestowed in me is pure; You created it, You formed it, You breathed it into me and You preserve it within me. You will eventually take it from me, and restore it in me in the time to come. So long as the soul is within me I give thanks to You, Adonoy my God, and God of my fathers, Lord of all creatures, Master of all souls. Blessed are You, Adonoy, Who restores souls to dead bodies.

So the Frank Underwood quote above is indeed correct: sleep is a kind of mini-death. In fact, the Talmudic sages calculated that it is 1/60th of death – that ratio being the minimum threshold of perception. By these lights, there is a natural, built-in mechanism every person has that essentially renders them partially dead for approximately 8 hours a day – unable to connect with the day to day business of the material world.

Like the prophets of old who needed to enter into a trance state that rendered their bodies inert so that their consciousness could be free to interface with higher dimensions, we accomplish the same end through the simple act of sleeping – the time in which we most directly interact with the subconscious. According to Kabbalah, in the same way that the body naturally sifts and filters out the good from the bad, our souls need to go through a similar cleansing process that is accomplished through sleep and dreaming. And, like a spy living a second existence in a land far from home, it needs to regularly “check in” with the homeland to stay balanced and focused on the mission.

As multidimensional entities, we human beings live simultaneously in both the physical and spiritual dimensions. Our minds are appropriately divided to live in both worlds. Our conscious mind deals with our physical dimension. Our unconscious mind deals with the spiritual dimension. Rabbi Ariel Bar Tzadok

At present, cognitive science cannot explain either the need for the type of sleeping we do nor how consciousness arises in the first place. Cultures around the globe have consciously sought access to the unconscious in a host of ways and even modern psychology has fixated on an aspect of this ancient assumption – that there indeed is a hidden dimension to the mind worth exploring. Could it be as the ancients have stated? Are our souls unshackled to roam on high as we sleep?

It’s a tantalizing idea. According to Jewish thought, the answer is yes.

For Rabbi Jacobs’ podcast version of these ideas (including three songs on the topic of sleep) please visit The Secret Chord.