The immune system has actual sensory feedback from protein measurements and biological experimentation on living adversary models. ... novelty is generated but cannot feed back into the nucleus except that it can because immunity controls scent and the love instinct itself is the power of immunity to pass genetic information the immunity is always recognition of self and the recognition of self in other which is only one part of love derives biologically from histocompatibility the ability to host one another's genes (enabling transplant of organs). ... identity. ... known in biology as tolerance. ... primary and secondary forms but hormone pheremone compatibility is a tertiary form of tolerance, in evolutionary theory as a goal, the MHC majored histocompatibility complex, the genes will evolve to sense and advantage gene's sense of self which is to implement a distributed program on the biological entities  expressing the gene. This is to say both everything and nothing, since understanding distributed programs is hard. Most people do not understand their own programming. The histocompatibility balance sought by pheremones is not identity with self but acceptance from other of validated genetic novelty. But sense of self is the test of authenticity used to validate novelty. The expensive to counterfeit recognition of protein equality, if the protein is slightly mutated it is supposed to be accepted from gametes, this allows the biological program to iterate through DNA states in a given region over time and close the mutation range as needed. If the protein is radically mutated it could be another species though we humans today getting false positives on most people and false negatives on few foreign infections. All these programs get trapped into environments where they just try to maintain compatibility with a genetic environment mostly. Mostly protocol compatibility with other programs. So the key to being highly conserved is to be the protocol in use by the most other programs. The energy metabolism in every cell for example is chemically compatible for every process, corresponding to genetic distributed program protocol compatibility between DNA programs, ultimately represented as a form of fuzzy integer equality operation on DNA integers! That is immunity: fuzzy integer comparison of DNA implemented using DNA itself. The DNA is double-stranded allowing strict integer comparison but eukaryotes added fuzzy comparison immunity sense of self validation of novelty through sexual division and recombination. The DNA computer gains another fundamental operation the floating point unit is added next to the CPU in the genetic program and it changes everything.