Introduction and Background
- Michael Levin’s early interest in how things are built (sparked by a TV) led him to explore both engineering/computer science and biology. He was interested in the way that both physical machines could create images on a screen and insects could perform behaviors.
- He became fascinated by how minds emerge from physics and chemistry, driving his focus on developmental biology.
- Levin’s perspective: standard developmental biology courses may offer a different, potentially more gene-centric view than his.
Genes, Hardware, and Software
- Genomes primarily describe the *hardware* of cells (protein sequences), not the overall organismal form (symmetry, number of limbs, etc.).
- Biological systems have both a hardware layer (genetics) and a crucial *software* layer (developmental physiology and decision-making processes). The software is dynamic and critical for navigating complex development.
- The mapping from genotype (genetic information) to phenotype (observable traits) is complex, not a simple one-to-one relationship, except in cases such as specific enzyme production.
- “Froggle” example: Mixing frog and axolotl cells creates a creature whose leg development can’t be predicted solely from the genomes, demonstrating the importance of cellular decision-making (software).
- Evolution selects for phenotypes (final outcomes, like anatomy and behavior) yet it’s genome (raw information) that get’s past on between generations, illustrating how interconnected and codependent each system.
Explaining Emergent Properties
- Explaining biological features requires considering both genetic factors and “free lunch” properties arising from physics, geometry, and computation.
- Galton board example: The bell curve shape arises from the system’s setup, not inherent in the wood, nails, or marbles individually. Emergent property from simple components and organization.
- Transistor example: Connecting transistors creates logic gates with truth tables that are inherent properties of the configuration, not something separately evolved.
- Biological systems can harness “generic laws” (as discussed by Stuart Kauffman and Stuart Newman) that are not explicitly encoded in the genes.
Cellular Decision-Making and Bioelectricity
- Cells and cell groups have agency (preferences, behaviors) and make decisions. Evolution shapes these behaviors through signals between cells.
- Individual cells have small-scale goals (pH, metabolic state). Multicellular collectives pursue larger goals (limb formation).
- Electrical networks, formed by connecting cells via gap junctions, are crucial for scaling up goals and collective intelligence.
- Gap Junctions allow a collective’s identity to fuzz out as molecules such as calcium merge together making multiple cells share a connected physiological signal. From a cells point of view it is a ‘false’ memory, from the collectie, it is real, causing a Mind-Meld, where memory is not longer ‘owned’.
- Homeostasis comparison: Single cells measure, remember, and act on their *local* environment. Connected cells in electrical networks measure, remember, and act on a *larger, non-local* scale, facilitating collective goals and response.
- Scaling of stress: Cells communicate stress (deviation from desired state) through shared signals, promoting plasticity and coordinated action to achieve collective goals. Individual stress becomes a shared problem.
Cancer as a Breakdown of Bioelectric Communication
- Bioelectrical signals create a larger sense of “self” across cell groups.
- Cancer can arise from cells becoming electrically disconnected from the larger network. They revert to their ancient, unicellular goal: to divide and go where resources are good (metastasis).
- Cells becoming disconnected (becoming cancerous) isn’t from increasing ‘selfishness’, rather it is a consequence of it shrinking, going back to their more selfish individual states, acting individually.
- Oncogenes often shut down gap junctions, the very first step towards bioelectrical disconnection, isolating cancer cells from the larger collective control.
- The study of bacterial biofilms shows that brain-like behaviors (using ion channels) evolved long before nervous systems, indicating the ancient roots of bioelectric communication.
- Morphespace: where good regions/bad regions, like barriers/obstacles are navigated similar to normal 3 dimensional space except now we are in a world of configuration.
Memory and Bioelectric Circuits
- Bioelectrical networks literally store a kind of memory, representing the “set point” or target morphology for regeneration.
- Planarian example: Cutting a flatworm into pieces results in each piece regenerating a complete, proportional worm.
- This implies that is must be a form of homeostatis going on; a complex non-neural form of a collective intelligence to keep such anatomical patterns consistent.
- Bioelectric pattern can be visualized (with voltage-sensitive dyes) and *rewritten* (using ion channel drugs) to change the body plan (e.g., creating two-headed worms). No genetic changes are required.
- That two-headed worms consistently produce two-headed worms is evidence of a true memory.
- The altered body plan is heritable through *fission* (splitting), demonstrating non-genetic inheritance. The bioelectric circuit acts as an additional hereditary medium. Not all inherited traits are DNA-based.
- Bioelectric circuit in planaria example; if the system’s physiology first ‘boots’ the bioelectric default circuit of number of head. This number-of-heads can also be edited non-genetically by altering the signals for short-term using inputs (tapping buttons on a calculator), creating a two-headed work without ‘rewriting’ the program.
The Eye Experiments
- Early frog embryos show a bioelectric pre-pattern that predicts the location of facial organs, including the eyes.
- Injecting ion channel RNA into other areas of the embryo (e.g., tail, gut) induces the formation of ectopic (out-of-place) eyes, demonstrating that bioelectricity is *instructive* for organ formation, and it is not merely for house-keeping.
- This revealed the modularity of development: The researchers didn’t need to specify *how* to build an eye, only *where*. The cells organized the complex process themselves.
- Cells recruited neighboring cells (even those not directly affected by the injected RNA) to participate in eye formation, showcasing multiple levels of instruction.
- Cells outside the traditionally defined “competent” regions (anterior neurectoderm) can, in fact, form eyes, highlighting the limitations of gene-centric views. It is not the top of the hierarchy, voltage is!
- Pac6: normally makes eyes, is found at anterior norectoderm, which will define competency for creating an eye, yet, other parts can.
- Ectopic eyes connected to the spinal cord (not the brain) could still mediate vision, demonstrating remarkable plasticity of the nervous system and its ability to interpret novel inputs.
- These examples were made early in Levin’s carreer, predating later research.
- Neutral Mutations; deleterious mutatuions, once lethal or severe can instead turn to be less sever or become neutural, broadening the landscape where evolution can progress towards.
Multiple Levels of Control and Goal-Directedness
- Biological systems exhibit multiple levels of emergence and control.
- Choosing the *right* level for intervention (e.g., bioelectric pattern vs. gene expression) is crucial for effective manipulation. Bioelectrical manipulation is often more effective and efficient than trying to micromanage genes.
- Instead of dealing with 10s of 1000s of individual parts/mechanisms, one could tap in further up the decision chain and deal with an intelligent system that navigates the complex decisions, taking away the stress of needing to handle the details.
- Biologists often exhibit “teleophobia” (fear of attributing goals or agency to biological systems), but cybernetics provides a framework for understanding machines with goals as a *continuum*, not a binary (dumb vs. smart). This is no longer considered “magical.”
- Telephobia came from needing to study all other entities as clocks since early days did not know how to interpret a human’s inner thoughts.
- Agency claims are *engineering* claims, testable by experiment (e.g., identifying, reading, and rewriting set points in a homeostatic system).
- Thermostat Example: how to test? look at what its level: is, is a setpoint?, 2 can we read/decode setpoint, rewrite? to rewrite is a new rewiring needed (like mechanical clock).
- Thermostat continued: after test; if thermostat work as expect, a trust/enginner dependency. No micromanaging is needed, temperature managed; good!.
- Genetic pathways can be *trained* (similar to neural networks), exhibiting various types of learning (including Pavlovian conditioning). This challenges the idea of purely deterministic gene regulatory networks.
- Implications for associative-learning, in a petri-dish there exists too powerful of a drug yet we cannot apply to humans, give both drugs, then give only nuetural one later; may or may not work.
- The molecular-placebo will activate only once paired enough times (Pavlov-style), where if the pairing stops, the original reaction (dog will drool from the bell ringing sound).
Placebo, Intention, and the Mind-Body Connection
- Intention can influence the body at multiple levels, including the bioelectric state of cells (e.g., deciding to stand up changes muscle cell voltage). The mind-body connection is strong and demonstrable.
- This suggests using levels of the hierarchy (chain of command) and speaking at the relevant part of the system to get tasks done.
- There is evidence of non-verbal “selves” within our bodies and we might be parts of larger selves.
- Learning is change withing one agent (human/machine learning, yet training (neural networks) implies multiple parties involved, at least one to create pressure (or lack-of pressure) and on receiver to change. The distinction could be helpful for exploring further discoveries.
- Minds emerge gradually during development. There’s no sharp dividing line between “just chemistry” and “having a mind.” This implies that minds exist in various forms across different scales of biological organization.
- We may be bad at recognizing unconventional intelligences because our perception is biased by our experience of the three-dimensional world of medium-sized objects moving at medium speeds. There are intelligences operating in other spaces (e.g., physiological space).
- Ethical questions arise from recognizing diverse forms of intelligence.
The Nature of Self and Identity
- A self is a collection of parts working together towards *system-level* goals (goals of the collection, not individual parts).
- Selves can be compared by the size and scope of their goals (“cognitive light cone”). A bacterium’s goals are small and local; a human’s can encompass larger spatial and temporal scales. Selves are nested, and humans may not be at the top of the hierarchy.
- We may be unable to fully understand the goals of a larger system of which we are a part (analogous to ants being unaware of the context of human actions). Mathematical formalisms might provide evidence for or against being part of a larger system.
- “A self is a *temporary* bundle of activities that work toward specific goals”: highlighting the agency nature that systems perform in different and potentially multiple cognitive landscapes.
- There’s a distinction between *learning* (changing your mind with the assumption of no external agency) and *being trained* (being changed by an external agency). It is an open, empirical question whether the external world has agency.
- Consciousness itself: is a hierarchy where “the more indeterminism (the space between what you could/cannot) is an indicator of the more level of agency that this form has”.
Scientific Inquiry and Open Questions
- Many phenomena should be treated as empirical questions rather than philosophical beliefs.
- Scientific frameworks both enable and constrain the kinds of questions we ask and experiments we perform. Our pre-conceptions, including being human-centric affects or decisions of intelligence (a dog being called intelligence as it is closer to our level).
- All science begins with an act of faith: the assumption that the world is understandable and that there are patterns to be discovered. It is important to be aware of this foundational belief.
- Current focus of Levin’s group: understanding different kinds of minds in various embodiments, with implications for regenerative medicine, birth defects, cancer, synthetic biology, and artificial intelligence.