Cycles

Every morning you wake. Every night you sleep. Every year, spring returns.

Your heart beats. Your lungs breathe. Your cells divide and die and are replaced.

The moon waxes and wanes. Tides rise and fall. Species flourish and go extinct. Civilizations rise and collapse.

Cycles are patterns that repeat over time—rhythms that structure reality from the quantum to the cosmic scale. Nothing stays the same, yet patterns return. Time is linear, but experience is circular.

Understanding cycles reveals how change and stability coexist. How endings enable beginnings. How the only constant is recurrence itself.

What is a cycle?

Periodic repetition

Definition: A cycle is a sequence of states or events that repeats over time, returning to its starting point before beginning again.

Key features:

Period: Time for one complete cycle (heartbeat: ~1 second, seasons: 1 year)
Amplitude: Size or intensity of variation (body temperature varies ~1°C daily)
Phase: Where in the cycle you are (full moon vs. new moon)
Frequency: How often cycles occur (breathing: 12-20 times per minute)

Not all repetition is cyclical:

Growth is repetitive but not cyclical (doesn’t return to start)
Random fluctuation repeats but isn’t periodic
True cycles have regular, predictable patterns

Types of cycles

Perfect cycles:

Mathematical (sine waves, circular motion)
Astronomical (planetary orbits, Earth’s rotation)
Highly regular and predictable

Approximate cycles:

Biological (circadian rhythms, menstrual cycles)
Economic (business cycles, market trends)
Climate (ice ages, El Niño)
Regular but with variation

Nested cycles:

Seconds within minutes within hours within days
Lunar months within solar years within precession cycles
Heartbeats within breaths within sleep cycles

Coupled cycles:

Predator-prey oscillations
Planetary orbital resonances
Synchronized biological rhythms

Natural cycles

Astronomical cycles

Daily cycle—Earth’s rotation:

24 hours, most fundamental cycle for life on Earth
Day and night, light and dark
Drives almost all other biological rhythms

Annual cycle—Earth’s orbit:

365.25 days
Seasons (from axial tilt, not distance from sun)
Migration, hibernation, breeding seasons, plant growth

Lunar cycle:

29.5 days, moon phases
Affects tides (gravitational pull on oceans)
Influences some species’ reproduction (coral spawning, sea turtle nesting)
Historical importance for calendars and navigation

Long cycles:

Axial precession: ~26,000 years (Earth’s wobble)
Orbital eccentricity: ~100,000 years (orbit shape changes)
Milankovitch cycles: Drive ice ages
Solar cycles: ~11 years (sunspot activity)

Why astronomical cycles matter: They’re the most regular, predictable cycles. They set the rhythm for nearly everything else on Earth.

Biological rhythms

Circadian rhythms (daily):

Sleep-wake cycles
Body temperature (peaks afternoon, lowest pre-dawn)
Hormone release (cortisol morning spike, melatonin evening rise)
Alertness and performance variations
Controlled by suprachiasmatic nucleus (brain’s master clock)

Ultradian rhythms (shorter than a day):

Sleep cycles: 90-minute REM/non-REM alternation
Alertness: 90-120 minute ultradian performance cycles
Hunger and feeding patterns
Cell division cycles

Infradian rhythms (longer than a day):

Menstrual cycle: ~28 days (hormonal, ovulation)
Seasonal affective patterns (mood changes with seasons)
Annual breeding cycles in many species

Circannual rhythms:

Hibernation patterns
Migration timing
Antler growth in deer
Even in constant conditions, internal yearly clock persists

Life cycles:

Birth → Growth → Reproduction → Death
But also: Species appear → Flourish → Decline → Extinction
Not repetition within one organism but pattern across generations

Ecological cycles

Predator-prey cycles:

Classic example: Lynx and snowshoe hare
More prey → More predators (with delay)
More predators → Fewer prey (with delay)
Fewer prey → Fewer predators (with delay)
Creates oscillating populations

Nutrient cycles:

Carbon cycle: Photosynthesis → Respiration → Decomposition → CO₂
Nitrogen cycle: Fixation → Assimilation → Decomposition → Denitrification
Water cycle: Evaporation → Condensation → Precipitation → Collection
Energy from sun, matter recycled endlessly

Succession:

Disturbance (fire, flood) → Pioneer species → Intermediate species → Climax community
Until next disturbance resets cycle
Forest fire regeneration, coral reef recovery

Climate cycles:

Ice ages: 100,000-year cycles (last 2.6 million years)
El Niño/La Niña: 2-7 year ocean-atmosphere oscillations
Atlantic Multidecadal Oscillation: 60-80 year cycle
Affect weather, ecosystems, human societies globally

Human cycles

Developmental cycles

Individual development:

Childhood → Adolescence → Adulthood → Old age
Not cyclical for one person, but pattern repeats across generations
Each stage has characteristic challenges and capacities

Life stages (various traditions):

Hindu ashrama: Student → Householder → Forest dweller → Renunciant
Medieval ages of man: Seven stages from infancy to senility
Erikson’s psychosocial stages: Eight crises from trust to integrity

Family cycles:

Marriage → Children → Empty nest → Eldercare
Generation cycles: ~25-30 years between parent and child
Family patterns often repeat across generations (for better or worse)

Social and cultural cycles

Generational cycles:

Strauss-Howe generational theory: ~80-year cycles
Crisis → High → Awakening → Unraveling → Crisis
Silent → Boomer → Gen X → Millennial → Gen Z
Each generation reacts to the previous

Fashion and trends:

Styles come back: 80s revival in 2020s
~20-30 year cycles in music, clothing, design
Nostalgia drives return of past trends

Political cycles:

Pendulum swings between left and right
Reform periods followed by consolidation
Populist waves recurring throughout history

Cultural mood:

Optimism and pessimism alternate
Trust and skepticism in institutions cycle
Openness and conservatism oscillate

Economic cycles

Business cycles:

Expansion → Peak → Contraction → Trough → Recovery
Average: 5-8 years, but highly variable
Driven by: Investment, credit, confidence, innovation

Kondratiev waves (long waves):

50-60 year cycles
Technology-driven: Canal age → Railway age → Steel age → Oil age → Information age
Each wave: Innovation → Boom → Maturation → Recession

Market cycles:

Bull markets and bear markets alternate
Bubble formation and collapse
Driven by: Psychology (greed/fear), monetary policy, real economic changes

Real estate cycles:

Roughly 18-year cycles (Fred Harrison)
Land speculation → Boom → Bust → Recovery
Driven by credit availability, population growth, speculation

Why cycles matter economically: Understanding position in cycle helps with investment, policy, and planning. But: Cycles aren’t perfectly regular, “this time is different” sometimes true.

Cycles in physics and mathematics

Oscillation and waves

Simple harmonic motion:

Pendulum swinging
Mass on a spring
Mathematical ideal: Sine/cosine functions
Period determined by physical properties (length, mass, stiffness)

Wave motion:

Water waves, sound waves, light waves
Energy traveling through medium (or spacetime)
Periodic in space and time
All waves are essentially cycles propagating

Resonance:

When driving frequency matches natural frequency
Amplitude increases dramatically
Examples: Pushing a swing, Tacoma Narrows bridge collapse, opera singer breaking glass
Both constructive (music, technology) and destructive (structural failure)

Quantum oscillations:

Electrons in orbitals
Quantum field fluctuations
Fundamental to quantum mechanics
Matter itself has wave-like, cyclical properties

Chaos and strange attractors

Deterministic but unpredictable:

Some systems cycle but never exactly repeat
Strange attractors: Patterns that loop without repeating
Lorenz attractor: Weather-like system creating butterfly pattern

Period-doubling route to chaos:

One cycle → Two alternating cycles → Four → Eight → Chaos
Found in: Population dynamics, dripping faucets, heart arrhythmias

Quasi-periodic motion:

Two or more incommensurate cycles combined
Creates complex but structured patterns
Found in: Planetary systems, brain waves, music

Breaking and disrupting cycles

When cycles break

Biological disruption:

Jet lag: Circadian rhythm out of sync with environment
Shift work: Forced misalignment with natural cycles
Seasonal affective disorder: Light cycle disruption
Health consequences of broken rhythms

Ecological disruption:

Climate change altering seasonal timing (phenological mismatch)
Species migration timing out of sync with food availability
Predator-prey cycles disrupted by human intervention
Coral bleaching: Temperature cycles exceed tolerance

Economic disruption:

Great Depression, 2008 crisis: Cycles breaking down
Monetary policy attempting to smooth cycles
Technology disrupting long-wave patterns
Globalization synchronizing or desynchronizing local cycles

Social breakdown:

Generational contracts failing
Traditional life stage patterns disrupted
Rapid change preventing cyclical repetition

Interventions in cycles

Medical:

Birth control: Interrupting menstrual cycle
Assisted reproductive technology: Bypassing natural cycles
Light therapy: Resetting circadian rhythms
Pacemakers: Imposing artificial heart rhythms

Agricultural:

Irrigation: Overriding rainfall cycles
Greenhouses: Controlling seasonal cycles
GMOs: Modifying plant life cycles
Disrupts natural cycles, increases productivity, creates dependencies

Economic:

Central banks: Attempting to moderate business cycles
Countercyclical policy: Stimulate in downturns, cool in booms
Success is debated: Smooth cycles or create new problems?

Climate:

Geoengineering proposals: Intervene in climate cycles
Risk: Unintended consequences in complex systems
Question: Can we safely manage planetary cycles?

The meaning of cycles

Impermanence and return

Buddhist perspective:

All phenomena arise and pass away
But patterns return
Birth-death-rebirth (literal or metaphorical)
Liberation means escaping the cycle (samsara)

Ecclesiastes: “A generation goes, and a generation comes, but the earth remains forever… What has been is what will be, and what has been done is what will be done, and there is nothing new under the sun.”

Eternal recurrence (Nietzsche):

What if everything repeats infinitely?
Would you live differently if every moment returns eternally?
Thought experiment about meaning and values

Cycles suggest:

Change is inevitable (nothing stays the same)
Permanence is also real (patterns return)
Both are true simultaneously

Renewal and regeneration

Destruction enables creation:

Forest fires clear deadwood, enable new growth
Economic recessions clear malinvestment, enable innovation
Personal crises enable transformation
Death enables new life

Each ending is a beginning:

Winter prepares for spring
Night prepares for day
Collapse creates space for renewal

Hope in cycles: “This too shall pass”—applies to both good times and bad times. Cycles mean nothing is final.

Time as spiral, not circle

Pure circle: Endless repetition, nothing new, meaningless Pure line: No return, no pattern, disconnected

Spiral: Returns to similar place but at different level

Seasons return but you’re older, different
History rhymes but doesn’t repeat
Each cycle learning, evolution, development

You revisit themes: Relationships, work, meaning, purpose—throughout life, but differently each time. Same issues, deeper understanding.

Living with cycles

Recognizing your cycles

Track your patterns:

Energy levels throughout day (identify your peak hours)
Mood variations (daily, weekly, monthly)
Productivity rhythms (ultradian cycles every 90 minutes)
Social needs (introvert cycles of engagement/retreat)

Women’s menstrual cycles:

Hormonal phases affect mood, energy, cognition
Understanding phase can help planning and self-compassion
Society often ignores this significant cycle

Seasonal patterns:

Do you feel different in winter vs. summer?
Energy, mood, motivation often vary seasonally
Adjust expectations and activities accordingly

Life stage awareness:

Where are you in your developmental journey?
What are the tasks and challenges of this stage?
Honor the phase you’re in rather than rushing to next

Working with cycles, not against them

Align with natural rhythms:

Sleep during your circadian low (typically 2-4 am)
Do difficult cognitive work during your peak hours
Exercise when your body temperature peaks (late afternoon)
Rest when tired rather than fighting fatigue

Plan for cyclical changes:

Know busy seasons (work, family, personal projects)
Build recovery time into schedules
Save during booms, spend carefully during busts
Anticipate rather than be surprised by predictable cycles

Respect rest phases:

Winter is for dormancy, not constant productivity
Fallow periods are necessary for future creativity
Downtime isn’t wasted—it’s part of the cycle

Use cycles strategically:

Plant during spring (metaphorically: start projects when conditions favor growth)
Harvest in fall (complete and collect results)
Prune in winter (eliminate what doesn’t serve)

Breaking harmful cycles

Personal patterns:

Addictive cycles: Trigger → Craving → Use → Temporary relief → Shame → Trigger
Relationship patterns: Attract same type, repeat same conflicts
Self-sabotage: Success → Fear → Sabotage → Failure → Comfort zone

Intervention:

Awareness: Notice the cycle
Interruption: Break the pattern at weak points
Replacement: Substitute healthier patterns
Support: External help to maintain change

Generational cycles:

Abuse, addiction, poverty often cycle through families
Breaking requires: Awareness, intentional change, support
You can be the generation that breaks the cycle

Social cycles:

Revenge cycles (feuds, wars escalating)
Polarization cycles (extremes fueling extremes)
Breaking requires: Someone refusing to retaliate, bridge-building, forgiveness

Cycles across scales

Micro to macro

Quantum: Particle oscillations, wave functions (10⁻¹⁵ seconds) Molecular: Chemical bond vibrations (10⁻¹² seconds) Cellular: Metabolic cycles, cell division (minutes to hours) Organismal: Heartbeats, breaths, circadian rhythms (seconds to days) Ecological: Predator-prey, succession (years to centuries) Geological: Climate cycles, ice ages (thousands to millions of years) Astronomical: Orbits, stellar lifecycles (years to billions of years) Cosmic: Universe expansion/contraction? (Unknown, possibly infinite)

Self-similar: The same cyclical pattern appears at different scales—fractal time

Synchronization across scales

Entrainment:

Smaller cycles lock onto larger cycles
Your circadian rhythm entrains to day-night cycle
Menstrual cycles can synchronize in groups
Fireflies flash in unison
Pendulum clocks on same wall synchronize

Desynchronization:

When cycles fall out of phase
Jet lag, shift work disruption
Predator-prey oscillations can desynchronize
Can cause instability or adaptation

Hierarchy of cycles:

Millisecond neural oscillations within heartbeats within circadian rhythms within seasons
Each level influences levels above and below
Multi-scale coordination creates healthy function

The cosmic perspective

Cyclic vs. linear time

Linear time (Western tradition):

Beginning → Middle → End
Creation → History → Apocalypse
Progress, development, teleology
Each moment unique and unrepeatable

Cyclic time (Eastern traditions):

No ultimate beginning or end
Yugas (Hindu ages), kalpas (cosmic cycles)
Samsara: wheel of rebirth
Emphasis on eternal return

Both true:

Cycles exist (empirical fact)
But: Universe evolves, things genuinely change
Synthesis: Spiral time—cycles within evolution

The universe’s cycles

Day and night: Local to Earth, but universal pattern—spinning creates light/dark alternation

Stellar lifecycles:

Nebula → Star → Red giant → White dwarf/Neutron star/Black hole
Takes billions of years
Creates heavy elements through cycles of fusion and explosion

Galactic cycles:

Sun orbits Milky Way center every ~225 million years
Galactic collisions and mergers over billions of years

Universal cycles?

Big Bang → Expansion → Heat death (most likely scenario: not cyclical)
Cyclical universe theories: Repeated Big Bangs and Big Crunches
Currently no evidence for universal cycles, but can’t rule out

Pattern: Cycles dominate at every scale except possibly the universe as a whole—which may be the one truly linear process

You are cyclical

Your components cycle:

Atoms were inside stars, will be inside future organisms
Carbon, oxygen, nitrogen cycle through ecosystems
You’re a temporary arrangement of recycled matter

Your patterns cycle:

Daily rhythms
Seasonal variations
Life stages echo others’ life stages
Your experiences mirror human patterns across time

You participate in cycles:

Breath exchanges air with atmosphere
Food connects you to nutrient cycles
Reproduction continues genetic cycles
Ideas and culture pass through you

From universal perspective: You are a brief eddy in larger cycles—a momentary pattern in endlessly recycling matter and energy, aware of the cycles you’re part of.

Practical wisdom

Accept the cycles

Resistance is suffering:

Fighting against natural cycles (aging, seasons, rhythms) creates stress
“Don’t push the river”—work with cycles, not against them

Everything passes:

Good times end (so savor them)
Bad times end (so endure them with hope)
This too shall pass—both consolation and warning

The only constant is change:

But change itself is cyclical
Patterns return even as specifics differ

Use cyclical thinking

Ask: Where am I in the cycle?

Personal energy (peak or trough?)
Project phase (beginning, middle, end?)
Economic cycle (expansion, peak, contraction, trough?)
Life stage (what’s appropriate now?)

Plan for full cycles:

Don’t expect permanent growth (plan for downturns)
Don’t assume permanent struggle (better times come)
Build in recovery periods
Anticipate rhythms

Invest countercyclically:

Buy when others sell (winter)
Sell when others buy (summer)
Be bold when others fear
Be cautious when others are exuberant

Create healthy cycles

Establish rhythms:

Regular sleep-wake times
Consistent meal times
Scheduled exercise
Predictable social connection
Creates stability through voluntary cycles

Build in renewal:

Sabbath/rest day weekly
Vacation annually
Sabbatical every 7 years
Retirement eventually
Allows sustainable long-term contribution

Ritual and ceremony:

Mark transitions (birthdays, anniversaries, seasons)
Create meaning through repetition
Connect to larger cycles
Ground yourself in ongoing patterns

Conclusion: The wheel turns

Cycles are perhaps the most fundamental pattern in the universe. Everything that exists does so in time, and time reveals itself through cycles—rhythms, oscillations, returns.

Cycles teach us:

Change: Nothing remains static
Return: Patterns repeat
Connection: We’re part of larger rhythms
Hope: After endings come beginnings
Humility: We don’t control the cycles
Wisdom: Align with rhythms rather than resist them

You are cycles within cycles:

Your heartbeat within your breath within your day within your life within human history within Earth’s story within cosmic evolution

The paradox: You are unique and unrepeatable (this moment never again), yet you’re also repetition of eternal patterns (like countless others before and after).

Both are true. You’re a novel expression of recurring themes—the universe experiencing itself through a temporary, unique, yet pattern-following form.

The wheel turns. Seasons pass. Cycles complete and begin again. You’re here for a few turns of the wheel—make them count, while recognizing you’re part of something vastly larger and endlessly recurring.

From the universal perspective, perhaps all of reality is one vast cycle—the universe breathing in and out, matter and energy dancing their eternal return, consciousness appearing and disappearing like waves on an infinite ocean.

And you’re here, now, aware of the cycles—which might be the point.

Further exploration

Books:

The Fourth Turning by Strauss and Howe (generational cycles)
The Clock of the Long Now by Stewart Brand (deep time cycles)
Rhythms of the Brain by György Buzsáki (neural oscillations)
The Great Wave by David Hackett Fischer (price cycles through history)
When by Daniel Pink (daily rhythms and timing)

Related topics:

Feedback loops - Often create cyclical behavior
Deep time - Long cycles of Earth and cosmos
Fractals - Patterns across scales, including temporal scales

Practice:

Track your personal cycles (energy, mood, productivity)
Observe nature’s cycles throughout the year
Notice where you are in various life cycles
Consider: What patterns repeat in your life?
Reflect: Which cycles serve you? Which should you break?