One common way to dismiss someone’s concerns is to tell them, “It’s all in your head.” If the person is projecting their personal issues onto a situation where they aren’t relevant, this response could be appropriate. However, our society tends to dismiss the relevance of “what’s in our heads” even when it’s of the utmost importance: for instance, when it comes to discerning the very meaning of our existence.
Our science-oriented culture places the highest value on things that can be studied objectively, that is, things that can be observed by more than one person at a time. In fact, repeated observations by multiple investigators is generally how we confirm that something is “real.” Nevertheless, there is no innate connection between how many people can observe a thing and how real it is.
Consider, for example, the sensation of pain. When you feel pain, this is an experience that is private to you. No one else is experiencing your pain; only you are. Other people may observe your wincing or moaning or writhing in agony, but those are the effects of your pain they’re observing, not the pain itself.
Even a scientist who was able to peer into the inner workings of the neurons that are correlated with your pain would not be able to observe the sensation of pain itself. That is a private experience, accessible only to you, the person who is having it. Does that make it unreal? I think you would be hard-pressed to convince anyone who is enduring intense physical pain that it’s not (Rawlette 2016).
Another point in favor of the reality of such experiences is the fact that they are the necessary starting point for all our knowledge about the world that lies beyond our experiences. For instance, how do I know that there is a desk in front of me right now? Because I am having certain visual and tactile experiences of a desk.
And, if I believe that the desk I’m experiencing is real and not just a hallucination, it’s because these experiences I’m having of a desk continue predictably over time and also cohere with the experiences that other people communicate to me.
The point is that none of us have any information about the reality of this desk or any other physical object except what comes to us through the medium of our own inner experience. Our first-person experiences are our necessary epistemic starting point, the thing about which we have the most certainty. We can then infer from them the reality of physical objects, but our knowledge of the reality of physical objects is dependent on our knowledge of the reality of our experience. If our experience isn’t real, we have no justification for believing in the reality of the physical world either.
It’s also important to realize that our knowledge about the physical world is much less detailed than our knowledge of our own experience. All we know about physical things is what we can abstract about them from our myriad individual experiences (Kastrup 2018). In this process of abstraction, we leave out any part of our experiences of these objects that differs from person to person or that differs when we use one observational device rather than another.
However, when we abstract from all the particular observations of objects in order to get at what is common across all of them, we aren’t left with very much: just facts about the objects’ spatial location and extension and how these properties change over time. We know nothing, for instance, about what the physical objects are in themselves.