That Idea of Red...

Human Nature as the Bedrock of Science and Knowledge

I wanted the first post here to go over the namesake of this page. It comes from a quote from David Hume's Treatise of Human Nature. The full sentence is

That Idea of red, which we form in the dark, and that impression, which strikes our eyes in the sun-shine, differ only in degree, not in nature.

Hume’s major work, in which this quote appears, is heralded as “A pinnacle of English empiricism… and a vigorous attack upon the principles of traditional metaphysical thought.” At least, according to the blurb on the back of my own copy of the book. However, I think only a very superficial reading of A Treatise of Human Nature, could lead you to such a conclusion. In fact, I suspect our blurbist might have never read the book they are describing, and are instead relying on the work of some other author summarising Hume. This misrepresentation of classic works seems like a common problem, among them Adam Smith’s Wealth of Nations, which I hope to come to in a later article. It is certainly true that the work did undermine Rationalism as it existed then, but, a reading in contemporary times, shows that is also strongly undermines empiricism as well.

Wikipedia defines Empiricism as “… an epistemological view which holds that true knowledge or justification comes only or primarily from sensory experience.” But in Hume’s quote, we can already begin to see the problem of calling his work “A Pinnacle of English empiricism…”; Hume is getting at the idea that, reality isn’t something out there in the world, for which can be described by such an incoherent notion as “letting the data speak for itself” but something that is in fact inside our heads. In a fundamental way, our imaginings are indistinguishable from sensory experience. Admittedly, at this stage, Hume’s quote could be interpreted in two ways, one of which supposing that our ideas and imaginings are nothing but some stored sensory input, but Hume clarifies otherwise, ultimately concluding that the notion of cause and effect, is not something that exists out there in the world, that exists in the sensory experience itself, but something that the mind projects onto otherwise discordant data. Hume sets up a thought experiment around repeated events, like billiard balls colliding, and says

Tis certain that this repetition of similar objects in similar situations produces nothing new either in these objects, or in any external body. For ‘twill readily be allow’d, that several instances we have of the conjunction of resembling cause and effects are in themselves entirely independent, and that the communication of motion, which I see result at present from the shock of two billiard-balls, is totally distinct from that which I saw result from such an impulse twelve-month ago… these instances are in themselves totally distinct from each other, and have no union but in the mind, which observes them… [the necessary connection between cause and effect], then, is the effect of this observation, and is nothing but an internal impression of the mind, or a determination to carry our thoughts from one object to another…The necessary connexion betwixt causes and effects is the foundation of our inference from one to the other… The idea of necessity arises from some impression. There is no impression conveye’d by our senses, which can give rise to that idea. It must, therefore, be deriv’d from some internal impression… Upon the whole, necessity is something, that exists in the mind, not in objects.

In modern terms, Hume is stating that it is some structure in the unconscious mind (internal impression), that gives rise to an interpretation of cause and effect, on the incoming sensory data. Note that “unconscious” is very distinct from “subconscious”; where the subconscious can be accessible to the conscious in certain circumstances, such as on deep reflection of your motivations and drives, the unconscious mind is by definition inaccessible to the conscious mind, in the same way that the functioning of the liver is in accessible to the conscious mind. In the same way that the idea of red cannot, by definition, be communicated to a person that has never seen colour. So yes, while Hume did undermine the rationalism of the time, he also, using a proof by contradiction, undermined empiricism, or the idea that data can speak for itself.

We can now come to a quote from the introductory section of his book, and understand properly what he is saying:

Here then is the only expedient, from which we can hope for success in our philosophical researches, to leave the tedious lingering method, which we have hitherto followed, and instead of taking now and then a castle or village on the frontier, to march up directly to the capital or center of these sciences, to human nature itself; which being once master of, we may every where else hope for an easy victory.

Someone who read this section after being misled by our blurbist, and therefore being under the impression that it was a pinnacle of empiricism, would most certainly be confused as to why Hume is placing the rest of the sciences, as subordinate to an understanding of Human Nature; a position that would appear in stark contrast to anyone that valued empiricism. Of course, now that we realise that Hume understood reality to, at least in its foundational structure, be a thing in our heads, the motivation for his value judgment here is obvious. For Hume, any and all sciences were ultimately, even if indirectly, studies of human nature; his thinking was thus that it would be appropriate to start taking a more direct route. The question that follows then: was Hume correct? Well, essentially, yes, and a large part of this page will be exploring that evidence and framework. But I’ll give some simple examples now.

For example, it has been experimentally determined that brain activation when hearing a song, appears identical in key parts as to when the same participants are asked to imagine the song. Furthermore, we have strong evidence now that infants are born with a sense of cause and effect that they project onto the world to make sense of it; assuming hidden causal mechanics where none are observable. The idea of red in the dark, and the one we see in the sunshine, are indeed indistinguishable in key respects, as far as we can tell. And further, that idea, before it has any content or meaning, appears to have an internally coherent structure in the mind, that projects onto incoming sensory data. Albert Einstein, who credits his inspiration for inventing Relativity in part to his reading of Hume, states:

The concepts and propositions get “meaning",” viz., “content,” only through their connection with sense-experiences…All concepts, even those which are closest to experience, are from the point of view of logic, freely chosen conventions, just as is the case with the concept of causality, with which the problematic concerned itself in the first place [referring to Hume]…

He then goes on to note a prejudice that develops from one not taking this seriously, that inhibits scientific progress

The prejudice—which has by no means died out in the meantime—consists in the faith that facts by themselves can and should yield scientific knowledge without free conceptual construction. Such a misconception is possible only because one does not easily become aware of the free choice of such concepts, which, through verification and long usage, appear to be immediately connected with the empirical material

Further, anyone familiar with information theory, the underlying theoretical understanding that allowed these things called computers to have been built at the scale they exist at, would notice a foundational similarity with Hume. As in A Treatise of Human Nature, information theory, as developed by Claude Shannon, also gives prime importance to the receiver of the data, as well as the sender and the data, in terms of what information is received. Shannon defines general information as a relation between the sender state, and the receiver state. Bluntly put, we have absolutely no way to formulate a coherent definition of Empiricism, if it is to be taken as the idea that “…knowledge or justification comes only or primarily from sensory experience.”, without at least, a huge qualification on “sensory experience”, as being something that is far removed from the idea of letting data speak for itself, and instead, sensory experience being something that itself defines the content of knowledge received.

So this will be the inspiration for this page, to explore the sciences and general inquiries of knowledge within the framework of understanding that they are all different aspects of a study of Human Nature. Some articles will take the more direct approach, that Hume suggested, while others will be more about the occasional castle and village.