Although there is truth in what you say to distinguish between knowledge of tangible things vs. conceptual things, Judaism teaches us another way to look at this. At first glance it seems counterintuitive but, when you think about it, you will see that it becomes a whole new way to look at knowledge.
In the secular world knowledge is rated by whether it is absolute or relative. Things which we have proven by trial and error to be a certain way become axioms; other knowledge is measured with the axioms as benchmarks to ascertain whether the next step is true or false. Something which we know to be absolutely true is the highest level of knowledge, as opposed to something which is relative knowledge, which may depend upon varying factors or someone’s opinion. That knowledge is subjective and not considered to really be knowledge at all, rather an opinion or a theory.
This is true in the world of science, where everything that is known was proven to be so, by either the 5 senses themselves or some extrapolation of the senses, sometimes using intellect, like mathematics, to extend our senses.
In the world of science, the knowledge of something less scientific, like the knowledge of one’s self, would not be knowledge at all, rather a thought, an opinion or an emotion.
We must realize, however, that all scientific knowledge, by definition, does not delve into the essence of things. It can measure them and tell you everything about their physical structure but it does not attempt to address their inner meaning. Indeed, according to science, there is no inner meaning.
According to the Torah, however, precisely that level of knowledge – the inner meaning – is defined as real knowledge. The knowledge attained by the 5 senses (essentially all of science) is important, of course, but is external knowledge. External knowledge, however important, in some respects is considered inferior to the knowledge of the essence of things.
This is not meant to minimize the crucial importance of science and all that we perceive with our 5 senses. That is the world we live in and we need to study it, understand it and enjoy it! We still need, however, to put things in proper perspective and realize the shortcomings that exist even in the most important of things.
Knowledge of one’s self, according to Judaism, is actually a higher level of knowledge, because it flows from the understanding of one’s very essence and purpose in this world. Although it can’t be seen with a microscope or measured in a laboratory, the essence of one’s self, one’s very existence, is something very real and present. The knowledge of the essence of things is a much deeper, more meaningful level of knowledge and is totally real to those who attain it. It comes about through deep contemplation.
Another way to say this is that each person has within him or herself a spark of G-dliness and knowing one’s self is to be in sync with the essence of one’s one unique G-dly spark.
Extending that knowledge further is to know G-d Himself, which is the deepest level of knowledge which exists in the world and flows from one’s knowledge of their own G-dliness. It also includes seeing the essence of things beyond what is perceived by the 5 senses.
Although, as I mentioned, all this might seem counterintuitive, give it some thought and I think you will enjoy the realization of a deeper dimension of knowledge which you, and all of us, possess.
Rabbi Yerachmiel Fried