Lots of philosophies talk about an objective world that exists outside of one's mind. Some philosophies even say that this objective world is the only thing that exists, and that subjective qualia are an illusion.

But anything that anyone has or will ever get to know to exist is their subjective experience. I think "existence" is synonymous with your subjective experience. I think "existence of an outside world" is not merely uncertain, but it's even meaningless.

How can objective existence be given meaning?

  • 1
    A thing exists objectively when it exists independently of subjects experiencing it. That is so even if anything that any subject gets to know to exist is their subjective experience. Things exist whether anyone knows that or not, and we can get by with just guessing that they do and acting accordingly. Since it works well enough we might as well drop the meaning of "know" under which we only "know" subjective experience and apply the word more usefully.
    – Conifold
    Apr 5, 2023 at 5:03
  • 1
    @Conifold but physics is merely a model to predict how your own perceptions behave. Physics is always tested in your own subjective experience. There need not be any notion of "objective existence" to make physics meaningful.
    – Ryder Rude
    Apr 5, 2023 at 5:11
  • 1
    This article address your question: The Absent Foundation. I guess the antithesis may be some form of panpsychism. However, Heidegger brings the foundation round to reason rather than a thing-in-itself, from "Nothing is without reason" - Leibniz. Apr 5, 2023 at 6:17
  • 2
    A concept that applies to everything, like your "subjective", is of no use at all. This is why most people do not use it this way. Since what physics predicts, and much of what it doesn't, is out of our control we might as well call it "objective", and reserve "subjective" for something much more narrow.
    – Conifold
    Apr 5, 2023 at 9:11
  • 1
    I think that's the key: objective are things that you cannot control, and that intervene in your experience. For example, a tree in front of you is objective, and not subjective, because it is an obstacle to your subjective experience. What's objective is a series of blocks and constraints on your experience.
    – Frank
    Apr 5, 2023 at 13:48

2 Answers 2


I would propose the following demarcation: in your subjective experience, there are things that resist and act as obstacles to your will, or constraints on your subjective experience.

For example, no matter how hard you try, if you jump up, gravity will bring you down. Furthermore, that is the common experience of everybody else that you perceive in your experience.

Those things that resist or act as constraints on your subjective experience, we could call "objective". They appear to your subjective consciousness but they are outside the reach of active control of the subject and thus are not located within the subject. They are given to the subject as constraints, and those things we can say exist objectively.


The common sense answer is that in your mind you create a model of the world around you based on input from your senses. The external world is the set of things that your senses are detecting. Clearly the model you create in your mind is not an accurate or complete model of what exists outside. It is a selective and subjective model, no doubt geared to the needs of our more primitive ancestors, for whom the ability to perceive the world was a matter of survival in a Darwinian sense. It is also possible for your mental model to be subject to hallucinations or imaginary effects, which render it even less like the 'real' outside world.

If you wish to establish with more certainty the extent to which your mental model is a realistic one (ie that it maps to attributes of external reality in a way that is consistent) then there are two obvious categories of test you might employ. One is to compare your model with those created by other minds- do other people appear to perceive the world in a way that is compatible with your perception of it? If so, then you might be inclined to conclude that your model is not a purely personal figment of your imagination. The other is to create instruments which can detect and quantify the properties of the constituents of the external world. If I place a fragment of a potato chip in a computerised chromatograph, I can get a print telling me its chemical composition- something I cannot do with my senses alone.

Now consider your mental model, which you consider 'real'. I would say that in some sense it is anything but real. When you look at a tomato and see that it is red, the colour red is entirely a product of your mind. There is no red in the external world- there is only light of a certain set of frequencies which your brain interprets as red. When you smell a rose, the idea of a smell is purely imaginary- what exists in the outside world is certain molecules in the air which interact chemically with specialist cells in your nose. When you feel cold, that sensation is a mental interpretation of messages from your nerves which are triggered by effects that ultimately boil down to the interaction of infrared radiation and the molecules of surrounding material (air, clothing etc) with the molecules of your skin.

So, there is an external world- it is what is continued to be experienced by other people when you are asleep- and what is in your mind is an interpretation of it, one shaped by evolution and largely shared by other minds.

  • I'm sorry but this answer just asserts your thoughts, rather than justifying them. "Redness" or the "smell" are not fake. They are the only thing you know to exist. You also cannot use the experiences of "other minds" to conclude "objective existence" because you don't know that other minds exist. It is very wrong to reject the only things you know to exist.
    – Ryder Rude
    Apr 5, 2023 at 7:40
  • I did explain at the outset that my answer was presenting a common sense view, so if you believe that I do not know that other minds exist, then you are clearly not in the domain of common sense. What sort of justification would you find compelling? Apr 5, 2023 at 8:17
  • I'm looking for what it means for other minds to exist. I think it's a meaningless statement because you can't verify or falsify it in your experience . The only thing that you can verify is that your own subjective experiences like "redness" or "taste" exist.
    – Ryder Rude
    Apr 5, 2023 at 8:20
  • 1
    If you define 'existence' to apply solely to your mental sensations, then what term would you like to use to distinguish between the keyboard on which you have typed your comment and a purely imaginary keyboard in your mind. I assume you agree that there is a difference between the two. Apr 5, 2023 at 9:16
  • I don't have to believe that an actual keyboard exists. Physics only describes how our perceptions behave. Not that I strictly buy this, but I think that believing that your perceptions exist is the bare minimum consistent ontology of the world. The existence of anything else is redundant and of questionable meaning.
    – Ryder Rude
    Apr 5, 2023 at 9:20

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .