What are the core assumptions of the modern scientific community with which they use to view the world and formulate theories etc?

By assumptions I mean premises taken as fact (about the universe/reality) but which cannot be proven definitively.

I am not asking regarding theories whose validity is observable and repeatable in a laboratory such as gravity, but rather on theories not directly observable such as the origin of life, darwinian evolution, the age of the universe, or the multiverse.

(In discussing theories with God believing people, I see they have very different ways of explaining things like the evidence for common ancestry (evolution) or the age of the universe. What assumptions therefore are adopted by scientists which lead them to their conclusions?)

  • Hello and welcome to Philosophy SE. This question is (I assume unintentionally) extremely broad. So I will take a quick shortcut and say this: scientists assume that anything and everything that we can reliably perceive and/or measure in some way, is real. Anything we can imagine — but not perceive/measure — is possible, but irrelevant until we can actually perceive/measure it. The problem with any kind of god-entity is we cannot reliably perceive/measure it. The best that the religious can do is say "I have a personal feeling". Well good for them... but that is not reliable.
    – MichaelK
    Commented May 7, 2018 at 10:34
  • @MichaelK perceive/measure physically?
    – michael
    Commented May 7, 2018 at 10:36
  • To clarify: perceive/measure anything that manifests physically, that is to say: it affects the physical world (that is how we measure: we record how that thing we are measuring have affected the physical world). Anything that does not affect the physical world is irrelevant to science. Philosophy loves to dwell on such things, science does not.
    – MichaelK
    Commented May 7, 2018 at 10:37
  • but has the age of the universe been perceived physically? is that also not based on assumptions about the past? @MichaelK likewise for darwin's random evolution. lots of things there not perceived yet accepted as scientific fact
    – michael
    Commented May 7, 2018 at 10:39
  • The age of the universe can be derived from things that we can measure, like the red-shift, and cosmic background radiation.
    – MichaelK
    Commented May 7, 2018 at 10:40

7 Answers 7


There are varying assumptions, as not everyone agrees on what science is. However, there do seem to be some common patterns.

Indeed, the first common assumption is that "there are patterns in reality." We don't often think of this as an assumption, but science is basically useless unless there's some pattern to test. To this end, there is a focus on that which is repeatable and reproducible.

This assumption takes on two different forms, depending on where one is going with the science. The lesser form would be "patterns in reality which are repeatable and reproducible have value/worth." This is required for science to be a worthwhile activity. The stronger form would be "That which is not repeatable or reproducible does not have value/worth." This would be used as an argument by those who believe science is the only path to value. The idea that "there are no miracles" is fundamentally captured in this wording. If there were indeed miracles, and they had value/worth, then one could state that science misses something important.

A second axiom, which is somewhat related is "that which matters can be measured." Science operates on data. If that which matters cannot be reduced to data, science has a very hard time operating on it. This axiom also splits into two forms, depending on how severe of a wording is desired: "This which can be measured have value" is the lesser wording, and "That which cannot be measured has no value" is the stronger.

The third fundamental axiom that I'd name is "The value of a theory which has not been proven false asymptotically approaches the value of a true theory." Fundamentally, science relies on falsification of incorrect theories to propel itself forward. Theories which have not been falsified are given credibility, which approaches the credibility we give to truth. In it's simplest sense, this is Popperian falsification, but if you look into how that credibility is provided to these non-falsified theories, we see the patterns that philosophers such as Kuhn saw.


Most of science is a matter of testing the nature of external things to establish their properties and test causal relationships. That kind of work presupposes confidence in some stability of the nature of things and the causality of action, and it presupposes the validity of sense data and its ability to establish objective knowledge. Hence, philosophically speaking, I would say that the groundwork for science is the philosophical conclusion (not really an assumption so much as acceptance of certain philosophical arguments) that existence exists (i.e., the world external to the mind is real), that things in existence have a nature and follow causality, that the senses are valid and are able to objectively establish the nature of things (through various processes like the scientific process), and that objective knowledge is possible.

Now, all of that involves a lot of philosophical conclusions. Many working scientists take those things for granted and do not explore these philosophical issues, but those who are interested study the philosophy of science and study metaphysics and epistemology more broadly in order to form conclusions on these kinds of issues. No doubt there are scientists that disagree with the above positions, and interpret their scientific knowledge differently (e.g., as subjective knowledge, or as knowledge of mere "phenomena", etc.), but I suspect that the majority of scientists hold an implicitly objectivist realist philosophical stance.

  • +1 - interesting point about the stability of the nature of things. would you say that means an assumption of the way things are is the way they've always been?
    – michael
    Commented May 7, 2018 at 16:56
  • That would be too strong, since it would be a claim that things cannot change. Rather, science would proceed according to the philosophical conclusion (taken as an "assumption" for scientific practice) that whatever change things undergo is in accordance with their nature and follows causality. Scientists might also assume enough stability for their observations to be valid from one moment to the next during their experiments.
    – Ben
    Commented May 7, 2018 at 22:35
  • At root, it is the en.m.wikipedia.org/wiki/Problem_of_induction to which various stances exist. But once again it is not an assumption, and is open to question and revision, such as vacuum energy sponteneously creating particles
    – CriglCragl
    Commented May 8, 2018 at 13:16

I would still suggest, (even if you keep pointlessly deleting this):

1) No (or very rare) Miracles: Experiences present an underlying consistency that allows for similar actions to regularly result in similar results. (Thus, things 'stay known' long enough for progress to be made. We are not permanently stuck in the stage of 'pre-science' on any topic.)

We do not need an absolute moratorium on miracles, just a high degree of overall consistency. (So, claiming this is an anti-religious sentiment is abusive, whether you are religious or anti-religious. So is demanding that it must be stronger than it objectively needs to be in order to work, just to force it into a disagreement with religion.)

2) Distrust the ad hoc: Simplicity is a valuable quality for causal explanations to have, and there is a shared, if vague, human intuition for what is and what is not simple. (Thus there is a limited range of causal principles to consider at any juncture in normal science or in any one of Kuhn's revolutionary periods -- the ones that look forward and seem simple enough to pursue. So no anomaly can produce an infinite quantity of research, and a given revolutionary period can never be too long before it converges on a new paradigm.)

3) We can talk about truth: Logic and math, particularly probability theory now that we have invented statistics, work and are reasonably the same for everyone at some basic level. (Thus Popper's principle of falsifiability indicates explanations in normal science either will converge or will be overtaken by ones with better odds.)

  • by no miracles, would that imply the assumption is that there is no higher Power above nature (i.e. no God)?
    – michael
    Commented May 11, 2018 at 5:34
  • @m.r. No, it would not. And you already know that if you read the post. I do find the implication this is anti-God abusive, as I stated. Why would you purposely do something that you know bothers me because I said so in the post you are commenting upon?
    – user9166
    Commented May 11, 2018 at 5:41
  • just clarifying. that's the way i understood your post. i'll study it more. i do think that no God is an assumption taken by scientists, btw.
    – michael
    Commented May 11, 2018 at 5:54
  • @m.r. Then you are wrong. Many of the most prolific scientists have been and are religious. An assumption presumably would rather be that there is no God that meddles with everyday processes on a regular basis, hence nature overall doing what it does. This is basically what "no (or very rare) miracles" expresses. And this is perfectly reconcilable with the Abrahamic God(s).
    – Philip Klöcking
    Commented May 11, 2018 at 8:55
  • "no God that meddles with everyday processes on a regular basis, hence nature overall doing what it does" - right. and long term processes, i.e. since earliest beginning, i.e. big bang @PhilipKlöcking
    – michael
    Commented May 11, 2018 at 11:04

There are two answer to your question.

  1. Almost all scientific theories are taken 'for granted' we don't have to re-test them every time we come to a conclusion that relies upon them being true. I.e. if I want to test whether Ball A is bouncier than Ball B, I assume that the laws of motion apply equally to both balls, and that acceleration due to gravity is the same for both, etc..

Although we take these things to granted, we do allow for them to be disproved or to proved to be lacking; if new evidence arises that does so; but we may not seek that evidence out. Many of these theories are proven 'beyond reasonable doubt' but may never be proved to be 'absolutely true'

  1. We also have 'Axioms' in science, like we do in mathematics. Some of these 'Basic Assumptions' are things like "There are natural causes for things that happen in the world around us", "Evidence from the natural world can be used to learn about those causes.", and "There is consistency in the causes that operate in the natural world."

This question is too broad, and it is hard to see what is gained from such lists. People generally choose a cautious set, which usually exclude some brancges or areas of modern scientific practice.

The first really good definition of scientific method was thr https://en.m.wikipedia.org/wiki/Baconian_method identifying a process of i ductive reasoning.

As groups outside of the scientific community sought to take on trappings of appearing scientific, like Marxists claims for Historical Materialism, Popper sought a clearer boundary from the https://en.m.wikipedia.org/wiki/Demarcation_problem through idealising what he thought the scientific method should be, and how the scientific community should behave. His work helped make it clear that the process of hypothesis generation is not itself empirical, and saw identifying hypothesees that are falsifiable by experiments as the hallmark of science. Lots of people disagree https://en.m.wikipedia.org/wiki/Falsifiability#Criticisms

Kuhn looked at actual scientific developments in practice, putting much greater emphasis on science as a human culture, defined by it's members in regard to who accepted to be a member, and who and what ideas are not.

I would look to Wittgenstein, and the way in which we all think we know what a game is, but greatly struggle to generate sharp boundaries between a definition of game and not-game. Scientific method will take up or reject whatever assumptions the community needs to, as people make convincing arguments through reason and evidence.

It is not a holy book, there are no core axioms, it is a practice. Everything follows from the goals: using evidence and reasoned argument, as a community of people getting their hands dirty, to try and understand the world. Like any scientific truth, scientific method is tentative, constantly subject to and open to revision.

  • not asking for definition of the scientific method. asking what are the assumptions taken for granted
    – michael
    Commented May 7, 2018 at 17:01
  • "So that's the difference between science and other things that comes up when people pretend to have the authority of science for things that aren’t science. But on the bigger picture, the more important demarcation is between reason and unreason." David Deutsch, on samharris.org/surviving-the-cosmos
    – CriglCragl
    Commented May 15, 2018 at 0:03
  • but reason is just logic and the conclusions of logic are determined by the premises adopted. i'm asking on the premises adopted
    – michael
    Commented May 15, 2018 at 5:22

Actual Assumptions About How The Universe Works

1. There is no Cartesian Demon. Our senses may be error-prone, but in general, they reflect the real world.

This is probably the only true assumption on the list. If there is an actual malicious entity deliberately rewriting our sensory data with the intent of deceiving us, science just doesn't work. Not much we can do about that, so we just write it off as unlikely and hope we're right.

2. The world behaves according to some set of consistent rules that can at least be approximated.

This basically follows from the first assumption. We have rules that approximate the way the world works, so unless there's a Cartesian Demon screwing with us, we don't really need to assume this anymore.


Important Rules of Thumb

These aren't really essential assumptions, but they help make certain types of common mistakes much less likely, and as such are near-universal.

1. An experiment that nobody else can reproduce isn't an experiment; it's an anecdote.

People make mistakes and people lie. If the experiment can't be reproduced, we have no way to verify that one of those didn't happen.

2. It isn't enough for a theory to perfectly fit the existing data; it needs to make a prediction about something that wasn't used to create it.

It's possible to take any set of data, even completely random data, and construct a model that fits it perfectly so long as the model is complicated enough. (q.v. Overfitting). Such a model is useless since it will make incorrect predictions about any data outside the set it was constructed on. But conversely, if a model can make correct predictions about data it wasn't privy to, that's a good indicator that it will be able to do so again.

3. Sometimes weird things happen by chance

It might seem really weird to flip 4 coins and have them all come up heads, but on average, that'll happen once every 16 times you try it. As such, it's important to consider whether some weird result is statistically significant: how unlikely is it that this result would have happened by chance.

4. We will make mistakes

We're human. It's inevitable that we'll screw up. Our natural tendency when we come up with a cool idea is to try to convince people that we're right. But confirmation bias is a thing, and it's way too easy to overlook flaws if we do it that way. And if errors make it into the literature and other people try to build on them, that'll just waste everyone's time.

So first we try to see if we might be right, and then as soon as it looks like we are, it's necessary to assume we've screwed up in some horrible yet non-obvious way and do everything we can to find it ourselves. If we can't find it, then we submit it for peer-review, so other experts can look over it and find the errors that we were too stupid to notice ourselves. (And there will be some, even if they aren't show-stoppers). And if it makes it through peer review, then we assume (or at least hope) that any remaining mistakes aren't too bad, and publish.

Some mistakes will still make it through, which brings us back to the "reproducible experiment" rule. If a bogus result makes it into the literature, eventually someone will spot it, recognize the flaw in the experiment, and do a new experiment to confirm or disprove the result. And so the process continues.

  • so only what we can see and perceive with physical senses/instruments exists?
    – michael
    Commented May 10, 2018 at 6:08
  • max planck on the demon: "As a man who has devoted his whole life to the most clearheaded science, to the study of matter, I can tell you as a result of my research about the atoms this much: There is no matter as such! All matter originates and exists only by virtue of a force which brings the particles of an atom to vibration and holds this most minute solar system of the atom together. . . . We must assume behind this force the existence of a conscious and intelligent Spirit. This Spirit is the matrix of all matter." end quote. en.wikiquote.org/wiki/Max_Planck
    – michael
    Commented May 10, 2018 at 6:09
  • @m.r. Other way around. It's fine if there exist things that we can't perceive; we just can't study those. But if the things we do perceive don't at least reflect reality in some way, we're completely screwed. Planck isn't talking about the Cartesian demon, just some Spirit. The Cartesian Demon is a thought experiment in which a demon is constantly and deliberately giving us false sense data in order to deceive us. If one of those existed, we would constantly draw false conclusions.
    – Ray
    Commented May 10, 2018 at 17:45
  • @m.r. Also, quoting famous scientists isn't really useful unless they're backing any claims up with a solid argument or an experiment. Scientists can and do make mistakes (especially when they talk about things outside their own field; you should hear some of the utter nonsense Penrose has said about AI, for example. (And so, following my own advice, I won't comment on whether atomic physics suggests anything about spirits.))
    – Ray
    Commented May 10, 2018 at 17:53

Well, here are a few assumptions that influence, but seldom appear, in just about every science textbook and article:

  • Meteorites are a good representation of pristine solar system matter for the purpose of radiometric dating. This is critical for all of geologic aging over 50,000 years, which must never contradict the age of the earth that was determined by meteorite studies. (Patterson 1956)

  • The discovery of dark matter does not invalidate the Big Bang theory. This is critical for all cosmological aging over 5 billion years.

  • Adaptation is self-evident.

  • While scientific method can only validate repeatable phenomena, science explains origins and provides pre-historic aging nonetheless.

  • Scientists do not publish unscientific information, because of peer-review. Non-scientific publications, like "Scientific American" and "National Geographic" don't count.

  • Umm, Potassium-Argon dating is used for dating rocks that are hundreds of millions to billions of years old. No assumptions about meteors are involved in these measurements. Commented May 9, 2018 at 21:19
  • Outside of perhaps the Journal of the Philosophy of Astrophysical Evolutionary Geology, I'm pretty sure that the majority of papers get by without making any of those assumptions.
    – Ray
    Commented May 9, 2018 at 22:56
  • Any paper or article that reports values in the millions of years or calls a trait "an adaptation", or which asserts naturalistic origins, is influenced by one or more of these assumptions. Commented May 9, 2018 at 23:07
  • @elliotsvensson Perhaps. I've read hundreds of papers that have not done any of those things, though. There do exist branches of science that don't come up during arguments about creationism. The vast majority of papers in most fields don't care about any of these things, so it's a stretch to present them as universal assumptions.
    – Ray
    Commented May 10, 2018 at 2:02
  • I'm sorry for making myself out to be a cynical debater about creationism. My comment is applicable to places where science is presented as a source for explanations of origins, typically textbooks and popular articles. Commented May 10, 2018 at 17:12

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