An intentional agent forms an internal representation of a thing in its environment (glucose), enabling it to recognize, respond to, and process that thing. The internal representation has value and meaning to the organism in that it represents something good or bad for the organism - promoting or impeding its survival and reproduction.

Internal representations may refer to things in the environment. They bear a relation or correlation to that thing. They signify or mean that thing.

According to a helpful definition by the evolutionary biologist Eva Jablonka and neuroscientist Simona Ginsburg, “a sign refers to, denotes, designates, implies, points to or represents, something… A sign thus ‘carries’ functional information.”

In the realm of biosemiotics - the study of signs and meaning in living organisms and systems - scientists “use the term ‘sign’ to denote a ‘carrier’ of functional information: a predictive, designating or representing input (e.g., predictive sensory cue such as a black cloud signaling rain, an alarm call, a welcoming gesture, a word, etc.) that requires a process of interpretation that guides the interpreter’s actions and re-actions.”

Neuroanthropologist Terrence Deacon laid out a 3-nested conception of information in which the lowest level is just a quantitative measure of the content communicated by the information, and the highest level is the significance or meaning of the information:

1. Shannon information (referring to the mid-20th century theory by Claude Shannon) is the most minimal and basic conception of information.
2. Referential information, in which information is understood to be about something, is emergent from Shannon's information.
3. Significant - or useful - information is emergent from referential information.

Most learning by organisms is based on establishing correlations between things–correspondences or associations. Positive and negative reinforcement (rewards and consequences) in the process of learning by association leads brains to assign value to stimuli–“good”-ness or “bad”-ness.

The mental representations that encode and store this information mean something to the animal because they are correlated with something in the environment. The meaning associated with the representation is thus relational, derived from the correlations with the thing being referred to.

Symbols differ from simpler signs in that “the use of symbols requires analogical reasoning–the understanding that signs stand for things,” as evolutionary biologist Eva Jablonka and neuroscientist Simona Ginsburg explained. They noted that “language is the paradigmatic symbolic system, and for many, the very core of our humanity.”

The computational neuroscientists Ogi Ogas and Sai Gaddam noted that one of the most important and enigmatic forms of human mental activity is the investment of raw sensory information with private meaning in the form of language. Only human minds can forge a mental link between words and meanings easily, instinctively, and incessantly because only human minds have evolved resonant connectivity between our language module and other consciousness-generating modules in our brain circuitry.

Quantum mechanics, the fundamental physics theory that describes nature's physical properties at the scale of atoms and subatomic particles, is spectacularly successful in its practical and technological applications. But its interpretation leaves many unanswered questions about what it is really telling us about the fundamental nature of reality. One of several scientifically serious, credible contending theories is the “relational interpretation” of quantum mechanics proposed by the Italian physicist Carlo Rovelli.

According to Rovelli’ theory, objects don’t exist independently of each other; they only exist relationally, as defined by their interactions. The world is not composed of “things” that “have” properties. Rather, the properties of a system are determined when the system interacts with any other system - in relation to that other system. All aspects of the world are relational (even space and time).

Our brains are constantly pattern-seeking, ceaselessly making connections between things and habitually deciphering meaning from and assigning value to our experiences. As symbolic, analogical thinkers, our brains routinely create higher-level symbolic representations of the connections between various experiences, distilling the essence of perceived correspondences between those experiences into more abstract ideas —including existential philosophical contemplations about what it all means.

Social psychologist Roy Baumeister suggested that “the meaning of life is the same kind of meaning as the meaning of a sentence in several important respects: having the parts fit together into a coherent pattern, being capable of being understood by others, fitting into a broader context, and invoking implicit assumptions shared by other members of the culture.

And so we derive our narrative, a meaningful life story that weaves together all the parts of our identity and personal history. Importantly, our narrative includes all the ways in which we have had some relational effect, however small, on the people and other sentient beings around us - hopefully leaving them just a little better than they would otherwise have been if we had not been here.

We might paraphrase Rovelli’s explanation about fundamental particles: Our life is the ensemble of the ways in which we affect other lives around ourselves–and the ways in which they affect us. Our life exists reflected in everyone else.

The psychiatrist Irvin Yalom, who has written extensively about the challenges of coming to terms with our ultimate death, quoted a patient whose mother used to say of people who had died, “Look for her among her friends.”