Phenomenal Conservatism said: "If it seems to S that P, then, in the absence of defeaters, S thereby has at least some justification for believing that P."

The phrase: "at least some justification" indicates that the justification is not very reliable and quite weak.

If regarding the epistemology of common sense. I did not find the wording of this excuse. If possible, show how it should look.

But commonsense epistemology seems to have a pretty strong fix that is much stronger than phenomenal conservatism (PC) because PC relies on perceptual experience and subjective experience, while commonsense epistemology relies on intuition, and our everyday experience as well as these beliefs are generally accepted that are much more reliable sources.

Please show how justification is formulated using common sense epistemology and does it contain the phrase: "at least some justification" just as phenomenal conservatism or common sense epistemology does not contain this phrase and is a much more reliable conclusion? Is common sense epistemology a much stronger, more plausible, and more probable conclusion than phenomenal conservatism?

  • Is this a HW essay prompt?
    – Conifold
    Jun 22, 2023 at 9:40
  • @Conifold do you have an intuition about that, or some evidence?
    – Scott Rowe
    Jun 22, 2023 at 10:33
  • This is a personal curiosity. I believe that common sense epistemology is more reliable and stronger. But I did not find a formulation of the arguments of common sense epistemology anywhere, so I want to see how it sounds and whether the same conclusion is present in common sense epistemology as in phenomenal conservatism?
    – Arti
    Jun 22, 2023 at 12:25

1 Answer 1


There are a variety of "commonsense epistemologies", and also of objections to them, so what you are referring to is more than a bit unclear.


One of the most commonplace of "commonsense epistemologies" is direct realism -- that what we perceive, IS! The belief in the redness of apples, the sweetness of sugar, and the reality and solidity of a chair, is standard in most people before they encounter science.

But the validity of direct realism has been challenged effectively, both with philosophy, and science. Redness does not seem to be a property intrinsic to apples, but instead one ascribed by our brains to the activation of certain sensors in our cornea, and inferred back to the apple. Likewise for the sweetness of sugar, but with taste sensors in the mouth and nose playing the role of the cornea. Scientific realism asserts that a chair is mostly empty space, and what holds us up when we sit on it is the interaction of EM fields in matrixes of atoms, not any "solidity". And that chairs are amalgams, not examples of a Platonic universal, primarily identified based on their subjective utility to us, not some "real" essence.

The consensus view among science and philosophy is that direct realism is false, and has been clearly refuted by test cases. But one will still often encounter a few advocates of it, both among scientists and philosophers -- and more commonly among anti-philosophical "pragmatistic realists".


The replacement for direct realism for most scientists and philosophers is a subjective indirect realism. The process of epistemology as initially described by Karl Popper and modified by more recent studies of our unconscious processing, is:

Outside events trigger our sensors >> our unconscious brain post-processes these inputs, integrates them into likely phenomenon, and sorts them for criticality and salience, and creates a "story" >> which our conscious mind evaluates, sometimes querying for more careful examination of our sensory inputs >> leading to hypotheses about what we observed (which sometimes endorse, and sometimes overrule the "story" from our unconscious) >> for science hypotheses, a scientist then attempts tests to support, refute, or clarify a hypothesis, and modifies it using judgement based on those outcomes >> scientists then publish their hypotheses and test results, inviting peer evaluation and critique and further testing >> leading to other subjective judgements generally from other scientists about possibly better hypotheses >> when this iterative process of inter-subjective hypothesis improvement converges on a stable hypothesis that a consensus of scientists endorse based on its utility and reliability, this hypothesis is treated as a "fact" about the world, and is uses as data to test and develop other hypotheses.

This working model is behind almost all of our informal empiricism, and is what most science operates off of.

There IS objection to this model. The behaviorist/3rd person inclinations among some philosophers and scientists lead to attempts to do science without the "internal" stages.

There are also efforts to claim that facts have no judgement calls to them, despite the consensus of philosophy of science that empiricism can ALWAYS be overturned. The implication of uncertainty that the possibility of being overturned brings, is that a "fact" is actually a judgment call, as it is not certain by definition.

As a further challenge, this model strongly implies we have a "homunculus" within us that does our deciding, and the deriding of a "homunculus" is often a key feature of arguments for physicalism and against dualism. Therefore this model is challenged by physicalist philosophers who seek some way to do internal judgement without a judger. The problem and a variety of alternatives proposed are discussed in the SEP article on the Problem of Perception: https://plato.stanford.edu/entries/perception-problem/

I don't know if indirect realism and these various challenges to it are the "common sense epistemology" you refer to. If so, then currently THIS particular "common sense epistemology" is still the dominant view.


Another common set of assumptions that might qualify as "common sense epistemology" is what is called "folk psychology". Folk psychology is explicitly the primary target of attack in the writings of Paul Churchland, and he advocates for its replacement by a reductive neural net behavior description. Here is my review of one of his books: https://www.amazon.com/gp/customer-reviews/R5048CH7VMV78/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=0262032244

Churchland describes folk psychology as:

the belief that we are:

  • Self-conscious
  • Hold beliefs
  • Have emotions
  • Have the power of reason

This set of folk psychology views are also attacked and rejected by the Delusionists, most notably Daniel Dennett.

The best articulation of a defense of folk psychology, I have found in Richard Swinburne's "Mind, Brain, and Free Will". Here is a link to my review; https://www.amazon.com/gp/customer-reviews/R18J8OJA7QPLKX/ref=cm_cr_dp_d_rvw_ttl?ie=UTF8&ASIN=0199662576

Swinburne argues for folk psychology based on the evolutionary justification of the reliability of our conventional views. Here is how I summarized his argument:

His argument is a pragmatic one, based on the evolutionarily derived trustworthiness of perceptions and reasoning. If our consensus perceptions and reasoning were NOT trustworthy, we would not be able to rely on them to know pretty much anything. Only combustion dynamicists really understand what happens in a car’s engine, the rest of us need to trust them when they say how cars burn gasoline. We have to trust particle physicists to understand how gravity works, and why we don’t all float away. And trust our eyes that the stop sign we see really is red. Experiences and conventional knowledge MUST be trustable as a general rule, and any claim to dismiss either carries a high Burden of Evidence. This applies to what is called “folk psychology” in philosophy of mind, and Swinburne considers our experiences, perceptions, intentionality, and mental causal effectiveness as givens unless explicitly refuted by significant evidence.

Note that I cited "significant evidence" to refute our natural belief in direct realism, but the alternatives to folk psychology or indirect realism are far less well supported. So only one of these three views has been challenged with the sort of overwhelming evidence that Swinburne says we should ask for.

  • If we take such basic beliefs of common sense as the existence of other minds, the existence of the external world, does this belong to folk psychology?
    – Arti
    Jun 22, 2023 at 19:59
  • @Arti The development of beliefs in the reality of the physical world, and of other minds, occurs early in toddlerhood, and is generally when we are pre-lingual. Object reality is developed in the first few months of life, and object permanence at about 8 months. Theory of Mind matures over time, but that process starts at about 6 months. Neither of these beliefs are arrived at "rationally", nor do we remember how we developed them. Sure you can call them "folk psychology", but OP is almost never challenged, and TOM only rarely.
    – Dcleve
    Jun 22, 2023 at 20:40
  • Say which argument it looks like: 1. We develop our belief in other minds from childhood. 2. Our belief in other minds is described by the theory of mind. 3. We have no reason to believe that other people do not have minds. 4. Therefore, we believe that other people have minds until we have no reason to doubt the existence of other minds.
    – Arti
    Jun 22, 2023 at 20:42
  • I want to know how we justify our basic common sense beliefs. What arguments justify our basic beliefs?
    – Arti
    Jun 22, 2023 at 20:44
  • @Arti -- the "argument" is that of pragmatic effectiveness.
    – Dcleve
    Jun 23, 2023 at 3:58

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