Note: If you haven’t yet read part 1- “What is Consciousness and the Neuroscience behind Sleep and Dreaming”, please visit the following page: https://portermedium.com/2019/06/the-mystery-of-consciousness-part-1-defining-consciousness-and-the-neuroscience-behind-sleep-and-dreaming/.
Similarly, part 2- Theories of Consciousness and What Each Says about Life after Death, is here: https://portermedium.com/2019/06/the-mystery-of-consciousness-part-2-theories-of-consciousness-and-what-each-says-about-life-after-death/
Can Consciousness be Measured?
If I was to measure your intelligence, I would give you a problem and ask for you to solve it. Being able to solve the problem would prove that you in fact have a certain amount of intelligence.
If I was to measure your emotion, I would present to you emotional triggers and see how you respond. I would do this by either observing how your body reacts to them in terms of facial reactions (frowning, crying) or even through the use of physiological means (checking your cortisol levels, blood pressure). Since it is understood how emotions work physiologically and which chemicals are indicative of which emotions, measuring different chemicals would indicate the presence of different emotions.
In both cases of intelligence and emotion, there is evidence that they are present by what is left over (externalities). In the case of intelligence, the evidence would be the solving of the problem. In the case of emotions, the evidence would be either facial expressions, chemicals or physical indicators that are expressed (also externalities).
However, in the case of consciousness, the consciousness is not actually causing any tangible objective changes. In fact, objectively, there is nothing that consciousness is responsible for at all. There is no problem being solved, no chemical being emitted, no observable effect whatsoever. There would therefore be no measurable externalities to prove the existence consciousness since there would be nothing to measure.
The only way to actually prove the existence of a subjective experience would be to actually measure it from a subjective point of view. For me to do that, I would actually have to experience things subjectively as you or have you measure your own consciousness. Doing that would be akin to measuring a ruler by using itself and therefore be impossible.
Do Animals have Consciousness?
Since consciousness cannot be measured, there is no conclusive way to prove that animals are conscious beings. While animals do display a certain level of intelligence and emotion, that isn’t enough to prove that there are subjective perspectives underlying them. Intelligence and emotion are products of neural activity programmed via DNA and would exist even if there wasn’t a subjective sense of self. As discussed earlier, consciousness alone has no externalities, so there would be no tangible differences in their behavior if they in fact have consciousness as opposed to if they don’t.
Do Other Humans have Consciousness?
Similarly, there is no real way that I can conclusively prove that another human being actually has consciousness. This is not to say that other human beings don’t have consciousness, but merely that there is no sure-fire way to prove that they do, since consciousness can’t be measured. Sure, I can ask a person if they have consciousness. They can then positively affirm that they do. However, how would I really know that they aren’t simply programmed to provide such a response? For example, artificial intelligences can be programmed to respond to such questions positively; yet, such a response alone would not mean that they have consciousness.
At the risk of diving into too deep a rabbit hole, I think it is fair to assume that other human beings do have a subjective sense of self even if it cannot conclusively be proven. However, who’s to say that consciousness is experienced the same across different individuals? Could there be variations in how individuals experience subjective senses of self? Since the process of consciousness is shrouded in mystery, there is no real way to answer these questions. That being said, there’s no doubt that it’s interesting to think about.