Premises

  1. There are two possible types of observations of consciousness - subjective and objective. These are exhaustive and mutually exclusive.
  2. A comparison requires at least two of the same kind of observations.
  3. Before a comparison is made all results are possible - on any characteristic being compared the possible outcomes are between no difference and the maxim spread of possible values for that characteristic.
  4. Humans have made many subjective observations of consciousness, but we have never compared subjective observations. This is either because comparing subjective observations is impossible or because we haven’t discovered how.
  5. Humans have never made an objective observation of consciousness.

Argument

  1. B + E: Humans have never made an objective comparison of consciousnesses
  2. A + D + 1: Humans have never made any comparison of consciousnesses
  3. C+ 2: All possible results of a comparison between two consciousness are possible
    Therefore
  4. Any two consciousnesses could be exactly the same, since that’s one possible result of any comparison

Observations that would refute the above premises

  1. Find another way, besides subjective or objective to make an observation of consciousness.
  2. I believe it’s impossible to refute this without using a different definition of “comparison.”
  3. I believe it’s impossible to refute this without using a different definition of “comparison.”
  4. Demonstrate a comparison of subjective observations of consciousness. This would also provide an answer to philosophical arguments like the Inverted Qualia argument and Mary the Color Scientist.
  5. Demonstrate an objective observation of the characteristics of consciousness. At the very least this would necessitate being able to detect the presence of consciousness in any subject.

Additional examples. Here's some ways that may be helpful to think about how something as seemingly different as our individual consciousness could actually be compeltely (or nearly) the same.

  1. Consciousness could be like a heart. There are different ways for animals to pump blood or other fluids around their bodies, but humans have all evolved to use a single 'design'. It's true that there's some variance from person to person, but the structure and details of how they work are all the same. While not exactly the same (there's differences in size for example), the difference between one person's heart at two points during their life can be as large as the difference between any two individual's hearts.
  2. Consciousness could be like fingerprints. That's the classic example of biological uniqueness, no two are the same. While fingerprints may have properties that make them useful for unique identification, in terms of their purpose and function they all are nearly exactly the same. They exist to allow us to grip things better and have a better tacticle sense, from that perspective, of the way they're actually used, there's essentially no difference between most people.
  3. Consciousness could be like a molecule. Take H2O for example, while there are many other molecules that are very similar (they have two oxygen atoms, are polar, form crystal structures, etc.) there's only one molecule that will work for what the human body needs and they're all essentially the same.
  4. Consciousness could be like an electrons. This is perhaps more likely in some theories of consciousness where it's a universal phenomenom, or an undiscovered natural force, but is a useful example of the extreme possibilities in our universe. As far as we can tell all electrons are exactly the same, in fact there's even been suggestions that it's possible that all electrons are in fact the same thing. They may pick up characteristics from their environment, that have short term effects, but like all fundamental particles they just are the way they are. To have any other quality would be to be something completely different.