“What does objectivity mean?” Here I intend to answer this question as best I can, as rigorously as possible, because the concept is a very important philosophical foundation, one that there has been a tendency to deny outright in different historical schools of thought. With any luck this article will explain why the concept is actually a rather self-evident, justified and well-defined one, so that we may loosen the knots we sometimes tie ourselves in and get on with tackling real questions.
What does the dictionary have to say about the word “objective”? 
- Of or relating to a material object, actual existence or reality.
- Not influenced by the emotions or prejudices.
- Based on observed facts.
So this is how the word is used in the streets by everyday English speakers. These three definitions give us a general sense of what the word means; it quite simply refers to that which can be observed and verified. Some philosophers will speak of objectivity as that which is “intersubjective“; this phrase accounts for the shared nature of these observations. I don’t conceptualise the term in this way, because it seems to ignore inorganic sensors, but the point is that “objectivity” refers to that which is observable by more than just yourself; that which is scientific, physical, or more simply, real.
Things need not be verified by another person to be real. There might appear to be an orange in front of me, and I can test if I am “just seeing things” by reaching out and picking it up, smelling it and so forth. The reason this works is that there is a “sense-consistency” to the world; the test for whether something is “influenced by the emotions or prejudices” is to see if:
- Your own senses agree with the observation
- Other sensors also agree with the observation.
Note that “other sensors” includes other people, but it also includes detection and measuring devices, and an important thing to consider is that we can only know about these things through our own senses. So for something to be real, the various information about it needs to be “coherent” and non-contradictory. We know that the brain is a general-purpose pattern-recognition machine; it tries its best to “make sense” of its inputs, and that is how it forms its “conceptual model” of the world. This is why we experience many of the optical illusions that we do; these are the “controlled hallucinations” that can occur when our brain tries to use its expectations to make sense of its observations.
The outcome is that it’s no good calling something objective if you are observing it but every other person on the planet thinks you are crazy and a sensor cannot be built to prove the stuff exists. That would just be a very lucid hallucination, probably caused by information leaks within the brain; perhaps of the type that schizophrenics sometimes experience. And it would be very confusing.
Sense-consistency and coherency
A curious observation about the information that enters our field of awareness is what David Hume referred to as the “Principle of the Uniformity of Nature”. Our sense data is rather stable; there are deep regularities in its constituent information. It obeys the laws of physics. To be more precise, the laws of physics were constructed to describe it. Why is this world coherent in such a way? Why do the laws of physics not constantly change and confuse us?
One way of addressing this point is to note that much of the world is actually not “stable” at all. Almost everything is changing all the time, even if that change is slow. Physics, and science more broadly, is trying to describe everything that we observe, hence it should be expected that those descriptions and explanations start to converge on some kind of “truth”, as we make more observations and get better at theorising. Of course, this explanatory process helps us to perceive the world as coherent.
Another point is that the laws of physics have changed in the past. We used to think that Newton’s Laws described motion, but Einstein went on to show that no, they are only an approximation of the phenomena – one that could be improved upon. The trajectory of the universe did not change, but our understanding of it – the “laws” we understand it to operate by – certainly did.
Objects generally don’t just disappear or do other crazy things, and if they did, we would incorporate those facts into our model of the universe and consider it normal and expected. Clouds in dry air and stars that are too close to black holes can just disappear, but we don’t consider that crazy, because we have developed a physics by which to understand these phenomena.
Another way of understanding the stability of our experience is the anthropic principle; the truism that for us to be here in the first place, the universe has to have certain characteristics, one of which would be stability. Organisms cannot evolve without the right conditions. The anthropic principle is untestable and therefore unfalsifiable, because it relies on the (sensible) metaphysical assumption that the world transcends our experience of it. I will discuss this later, but the point is that it is a bit of a metaphysical cop-out, though it can be a helpful way of thinking about the “problem”.
The outcome is that it is irrelevant why our conscious experience of things is stable, just as it is irrelevant why we have a conscious experience of the world in the first place. These are not scientific questions; they are metaphysical and therefore unanswerable. We can speculate, and that might be fun, but it is of no scientific value. All that matters in understanding objectivity is that this world of ours is stable and regular and that our senses agree with each other, as well as with the information they provide about what other sensors and people observe. A thing that presents us with inconsistent data across our range of senses is not what we would call “objective”.
Things that are not objective
Hallucinations show us that it is possible to perceive things which are not real; which are inconsistent with other sensors. These perceptions do not fit into the regularity of the objective world; they cannot be observed by other people or sensing equipment, and they are often inconsistent with the rest of the subject’s own senses. Somebody might hear a voice and turn around to see that there is nobody there, for instance. This goes to show that just because something can be perceived, that does not necessarily mean it is real. That criterion is not strong enough for objectivity; we require an input to be demonstrably consistent with the rest of the incoming information before we call it “real”. That is the essence of verifiability.
But people are also happy to accept that things can be real merely in a sense, for example that Santa is real in the sense that he can be thought about. This is reasonable, because that fact is empirically verifiable at least through fMRI scans – we know that the patterns of information that represent this conception of “Santa” could, in principle, be found in memory.
If you ask someone to give an example of something that isn’t real, they’ll generally say “unicorns” or “dreams” or, again, “Santa”. These are, in the words of Donald Rumsfeld, the “known unknowns”. The things we might call “imaginary” or “fictitious” – we conjure them in our minds. The idea that there is a fat man flying around in a sled and giving children presents is totally devoid of evidence, and yet that does not stop us from imagining it to be the case; that is of course the essence of fiction.
We also have a word for the unknowable unknowns; the things which are not even imaginary; the “unimaginable”. An example would be pure nothingness – it is impossible to imagine the absence of information. Even darkness and silence can be described. This is metaphysical territory, and it is the stuff we presume there to “be” outside of the limitations of our experience. The problem is that existence is defined with respect to our experience, so there is no justification whatsoever for presuming that there is anything “outside” our existence. Such claims are outside the scope of evidence.
By way of summary, objective reality appears to be defined by its sense-consistency and coherency, and more specifically by the agreement of sense data, both personal and extra-personal, on the actual existence of a thing. A concept may also be “imaginary” and be available at merely a personal level, where sensing equipment, other people and even one’s other senses might not have access to the information. And then we presume that there is some category of things we cannot even conceptualise, and these might best be labeled as “unimaginable”.