There is an order to the Universe we live in.

Roughly speaking, little things affect big things. Not the other way round. This is something you already know: particle physics underlies nuclear and atomic physics; atomic physics underlies condensed matter and chemistry; and so on up the chain. It’s certainly true that it can be difficult to make the leap from one level to the next, and new creative ideas are needed at each step, but this doesn’t change the fact that there is an ordering. Big things don’t affect little things. This is the reason there are no astrology departments in universities.

But there is another aspect to this story, one which is not often stressed. Little things affect big things, but they rarely affect very big things. Instead, little things affect slightly bigger things. And these, in turn, affect slightly bigger things too. But as you go up the chain, you lose the information about what came long before.

This again is something that you know. A zoologist who is interested in the way that starlings flock has little reason to study the dynamics of the Higgs boson. It’s also the reason that science is possible in the first place: neither Newton nor Einstein needed to understand how quantum gravity works on microscopic distance scales to write down theories that work extraordinarily well on larger scales."


But in complex systems/ system theory (biology, climate science, etc.) we have feedback loops where big things indeed affect small things.

Is there any contradiction? If yes, how to resolve?

  1. Climate Change and Ecosystems:

    • Little to Big: Changes in local ecosystems, such as deforestation or urbanization, can affect larger climate patterns, like the heat island effect in cities impacting regional temperatures.
    • Big to Little: Global climate change can influence ecosystems and species distribution, with rising temperatures affecting the behavior and life cycles of individual organisms.
  2. Biology and Genetics:

    • Little to Big: At the genetic level, mutations in individual genes can lead to the emergence of new traits or diseases that impact entire populations.
    • Big to Little: Changes in the environment, such as exposure to toxins or different diets, can lead to epigenetic changes in genes, affecting the health and behavior of organisms.
  3. Economics and Market Behavior:

    • Little to Big: Consumer behavior and purchasing decisions of individuals can collectively drive market trends and impact the economy.
    • Big to Little: Macroeconomic factors, like interest rates or government policies, can influence individual spending patterns and investment decisions.
  4. Social Systems and Cultural Change:

    • Little to Big: Small interactions between individuals can shape cultural norms and lead to larger societal shifts over time.
    • Big to Little: Major historical events or shifts in power structures can influence the behaviors and attitudes of individuals within a society.
  5. Neural Networks and Cognitive Processing:

    • Little to Big: Individual neurons firing in specific patterns contribute to larger cognitive functions and behaviors.
    • Big to Little: Changes in brain structure due to experiences, such as learning a new skill or trauma, can influence the firing patterns and connections of individual neurons.
  6. Epidemiology and Disease Spread:

    • Little to Big: Individual behaviors like handwashing and vaccination can impact the spread of diseases in a community.
    • Big to Little: Government policies and healthcare infrastructure can influence individual access to preventive measures and medical care.
  7. Political Systems and Public Opinion:

    • Little to Big: Individual opinions and actions contribute to larger political movements and elections.
    • Big to Little: Political rhetoric and media coverage can shape individual perceptions and beliefs about issues.


  1. Butterfly Effect: The classic example of chaos theory, often described as "a butterfly flapping its wings in Brazil can set off a tornado in Texas." In this scenario, a small change in initial conditions (flapping of a butterfly's wings) can lead to magnified effects in a complex system (tornado formation), while the reverse (tornado influencing butterfly wing flaps) is less plausible.

  2. Epidemic Outbreaks: A single infected person can start an epidemic by transmitting a disease to others. The spread of the disease can escalate significantly from one individual to a larger population, without the wider population's state strongly affecting the initial infected person.

  3. Invasive Species Disruption: The introduction of a non-native species to an ecosystem can have drastic impacts on the existing flora and fauna. The behavior and characteristics of the invasive species can reshape the entire ecosystem, whereas the ecosystem itself doesn't usually have as direct an impact on the invasive species.

  4. Social Media Trends: A small group of influential users can initiate trends on social media platforms. Their actions can lead to widespread adoption of hashtags or challenges, whereas the overall social media environment doesn't usually have a direct impact on the actions of these influential users.

  5. Dominant Cultural Movements: A small group of thinkers, artists, or leaders can drive cultural shifts and movements that impact society as a whole. The behavior and ideas of these individuals can shape the values and norms of larger populations, with less immediate influence from the general populace.

  6. Opinion Cascades: In social networks, the adoption of opinions or beliefs by a few influential individuals can lead to a cascading effect where many others adopt the same opinions. The behaviors of these few individuals can disproportionately shape the larger discourse.

  7. Nuclear Chain Reaction: In a nuclear chain reaction, the fission of a single atom triggers the fission of multiple others, leading to a release of energy. The actions of individual atoms can cascade into a large-scale release of energy, while the overall energy environment has less direct impact on the behavior of individual atoms.

  8. Economic Bubbles and Crashes: The behavior of a relatively small number of investors or traders can trigger economic bubbles or crashes in financial markets. These market shifts can affect entire economies, whereas broader economic conditions might not have as direct an effect on individual trading decisions.

  • 1
    There is no contradiction besides in how these things are sometimes phrased; and besides the lack of contradictoriness, here, there is the question of reductionism, and all that has been said against reductionism in turn. More importantly, the accelerated expansion of the universe is not clearly an effect of either only the subatomic (the Casimir effect writ large) or only the macrocosmic (global spacetime evolutionary dynamics), but can be understood as a coalescence of these (and all intervening) factors. Sep 25 at 20:19
  • (I should add that the Casimir effect is not proven to be the cause of accelerated expansion, although it is the popular culprit.) Sep 25 at 20:19
  • epic moments in philosophy.stackexchange ha
    – user67675
    Sep 25 at 21:37
  • Plot twist: big things consist of many little things.
    – NotThatGuy
    Sep 26 at 7:56
  • 1
    Big things dont exist, it's an illusion. The only things that exist are little things; " Big Things" are just lots of little things. Sep 27 at 17:48

3 Answers 3


There is no contradiction. You have over generalized. Reduction, where little things are the causal drivers of big things, is GENERALLY true. But you have already identified one of the phenomenal that violate that. Emergence is real, and things like "flocks" and flocking behavior are NOT reducible to chemistry, or cellular biology, etc.

That reduction is useful, and generally applies, does not make your universal claims about causation only going one way true. Instead, do a Popperian test case, and you will find multiple instances where the causation goes the other way.

To understand our world, we need to use reduction, AND emergence, AND wholism, AND Whiteheadian process physics. NOT just reductionism.

  • so does big things affect little things ?
    – quanity
    Sep 25 at 20:48
  • Hmm. Big things, like my having a house that keeps the rain and wind off me, DO affect little things, like the 98.6 F temp most of my cells live at.
    – Dcleve
    Sep 25 at 20:58
  • i mean bidirectional see the whole question
    – quanity
    Sep 25 at 21:12
  • @quanity -- I posted this answer before you expanded the question with the long set of examples. Your question is no longer well formed -- half your examples are of higher tier system feedback loops that DO affect "small" things, yet despite that you retained your first 3 paragraphs which states absolutely and falsely that big things do not affect small things. You appear to realize this is untrue, but are now downvoting the answers that point out how higher tier emergent phenomena have causal effect on lower tier reduced phenomena, so the causal direction is not only one way.
    – Dcleve
    Sep 27 at 22:34
  • please Explain whiteheadian process physics.
    – quanity
    Sep 30 at 9:33

There is no contradiction. Your initial assumption that big things do not affect little things is literal nonsense. The Earth (a big thing) affects the motion of a ping-pong ball (a small thing). My lawnmower (a big thing) cuts blades of grass (small things). A centrifuge (a big thing) may be used to segregate different atoms (small things). A screwdriver (a big thing) can turn a screw (a small thing). A train (a big thing) can transport laboratory mice (small things). The Sun (a big thing) can affect an ant (a small thing). A trawler (a big thing) can catch a fish (a small thing). In condensed matter physics, a potential representing a crystalline solid (a big thing) governs the solutions to the Schrodinger equation which are the wave-functions of an individual electron (a small thing). In an elastic collision between a one tonne sphere and a one gramme sphere, the smaller sphere will undergo a more marked change of speed and direction than the larger sphere. Etc etc


little things affect big things. Not the other way round.

Such is a statement loaded of multiple subjective assumptions.


To start, what are "things"? In nature, there are no muffins, rainbows or clutches. In nature, everything is just atoms or quarks, fields, or something we don't know, but there are no "things" as such. And ALL atoms/quarks/fields/whatever, strictly, interact in some measure with ALL others (even if it is at infinitesimal levels).

So, if "things" are groups of those constitutive parts (there you have a definition of things), which depend on human physical and metaphysical potentials, they are made of those constitutive parts which are in permanent interaction. So, ALL things affect ALL things, independently of what you call "small" and "big".

In synthesis, when you speak of a "thing" you are speaking of what YOU subjectively determine as "thing", ignoring what others and the rest of the universe determine.

"little" vs. "big"

What is "little"? What is the limit between what is "big" and what is "little"? Quantum behavior? Thermodynamics macro vs micro? "Things" smaller than yourself? As measured by entities of what size? existing at what speed?

In synthesis, when you speak of "big" and "little" you are speaking of what YOU subjectively determine as "big" and "little", ignoring what others and the rest of the universe determine.


You speak about "things" that are "affected" by other "things". When you push the accelerator, the car moves faster. It is your foot "thing" that is affecting the car "thing"? It is the most extreme atom on your foot that starts all interactions that end up in what you understand as "car moving at a faster speed"? Quite a lot of subjective assumptions there...

In synthesis, when you speak of "effect" you are speaking of what YOU subjectively determine as "effect", ignoring what others and the rest of the universe determine.

Little things affect big things, not the opposite

So, a photon interaction can trigger a mental reaction that leads you to push the accelerator so the car can move faster, but not the opposite (that is, if the car moves faster, and you are inside, not a single photon interaction gets affected)? A butterfly can cause a storm, but a storm will not affect a butterfly?

I think you haven't meditated enough this idea.

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