thoughts. We have millions of thoughts that we think (and perceive and feel) unconsciously. We are constantly bombarded by millions of perceptions, feelings, thoughts and experiences, the sheer number of which is perhaps unquantifiable. Human neurology is structured in such a way that we are protected from "overwhelm" by these unquantifiable experiences. Our conscious minds work by screening out (or "filtering" out) the huge majority of thoughts, feelings and perceptions that we experience constantly on an unconscious level. If we didn't filter out this huge unconscious majority of our experience we would hardly be able to function because we would be so overwhelmed by the massive overload of unconscious thoughts. So these millions of "unregistered" thoughts end up living in our unconscious minds, and they become the fodder for our dreams, as Freud asserted. (Although Freud's definition of the unconscious mind was quite a bit narrower and is a bit outdated by today's understanding of the "unconscious" mind.)
Perhaps another way to interpret the "proverb" is simpler: Time and space represent surface aspects of our external awareness. Conscious thoughts represent a surface aspect of our internal awareness. Therefore both are meaningless, relatively, when compared to the totality of our awareness, both conscious and unconscious.
I think a person could drive herself a little bit bonkers trying to figure out what some of the denser proverbs actually are trying to say. Often there are multiple interpretations so you can't assume that the interpretation you've come up with is the most accurate.
I was trained as a psychotherapist in California, and I have had over thirty years of experience in helping people through therapy and coaching. I hold a Ph.D. degree in psychology, and I have dedicated the focus of my work to the practice of Life Coaching.