Chapter 2: Root Cause - The Three-Layer Framework Deduced from First Principles

This chapter merges two foundational articles on the Root Cause Medicine framework.

Part I: On the Computational Framework for Root Cause Medicine

Author: Xiong Jianghui

The Problem: The Medical Paradigm Dilemma from "Treating Symptoms" to "Treating Root Causes"

Modern medicine faces a profound paradox: despite enormous advances in diagnostic technology, drug development, and clinical intervention, treatment outcomes for complex diseases remain disappointing. As noted in a paper (Network pharmacology: curing causal mechanisms instead of treating symptoms, Trends Pharmacol Sci. 2022 Feb;43(2):136-150), most drugs have extremely low efficacy against complex diseases, and drug discovery success rates continue to decline. The root of this dilemma lies in the current medical paradigm of "organ-centrism" and the dogmatic thinking of "one disease, one target, one drug."

The traditional medical model treats disease as isolated organ pathology, with treatment strategies focused on symptom relief rather than correction of causal mechanisms. This approach ignores the systemic nature of disease — most chronic diseases are not failures of a single organ, but comprehensive manifestations of multi-level, multi-system dysfunction. The rise of network pharmacology and systems medicine is precisely a response to this dilemma: we need to replace descriptive disease phenotypes with causal, multi-target signaling modules to achieve precise and effective therapeutic interventions.

In the fields of functional medicine and longevity medicine, many scholars and clinical experts have raised the issue of identifying the root causes of diseases and phenotypes, considering this a common and consensual need for the next generation of medical systems. However, the theoretical foundations for root cause analysis — especially practical tools and computational frameworks — remain lacking in systematicity.

Facing multi-omics data, functional medicine and longevity medicine practice has gradually accumulated vast amounts of genomic, proteomic, metabolomic, exposomic, biological age, and epigenetic DNA methylation data. How to integrate these data, discover root causes, and identify intervention targets is an enormous challenge. Many experts place their hopes on AI development, expecting AI to aggregate and integrate massive data and generate insights.

I believe the above approach follows inductive reasoning — the approach of experimental science. To solve the problem of multi-omics data integration and root cause discovery, we may need to shift perspective — abandon induction, turn to deduction, and starting from first principles, establish a general theoretical and computational framework. Therefore, based on my proposed Capomics theory, I now propose a three-layer computational framework for Root Cause Medicine — the phenotype layer, the functional layer, and the root cause layer.

First Principles: From "Structure-Function-Capacity Reserve" to the Three-Layer Architecture

The core idea of Capomics theory can be summarized as: structure determines function, function generates capability, and capacity reserve determines health status. This idea permeates every scale of the living system — from molecules, cells, and tissues to organs, systems, and the whole organism.

- Structural level: DNA sequences, protein folding, organelle morphology, organ anatomical structure

- Functional level: Gene expression, enzymatic reactions, mitochondrial energy production, cardiac pumping

- Capacity Reserve: DNA repair capacity, antioxidant capacity, metabolic adaptation capacity, organ functional reserve

The essence of disease is the depletion of capacity reserve. Young and healthy individuals possess ample capacity reserves to cope with various internal and external stresses; disease states occur when capacity reserves fall below critical thresholds and the system can no longer maintain homeostatic balance.

The three-layer architecture of Root Cause Medicine is constructed based on this first principle:

- Phenotype layer corresponds to "the external manifestations after capacity reserve depletion"

- Functional layer corresponds to "the intermediate process of capacity reserve decline"

- Root cause layer corresponds to "the underlying mechanisms leading to capacity reserve depletion"

Theoretical Rationality of the Three-Layer Architecture

1. The Necessity of the Phenotype Layer: The phenotype layer is the "entry point" of medical practice. Its limitation lies in its non-specificity and latency.

2. The Criticality of the Functional Layer: The functional layer reveals "why these phenotypes appear." It represents the capacity decline of organs and systems — organ aging, metabolic aging, immune dysregulation, neurodegeneration.

3. The Determinativeness of the Root Cause Layer: The root cause layer contains the most fundamental molecular-cellular mechanisms, which are the "prime movers" of disease occurrence.

The Aging Hallmarks (López-Otín et al., Cell, 2013, 2023) and Cancer Hallmarks (Hanahan and Weinberg) serve as the core content of the root cause layer because they satisfy three criteria: causality, universality, and intervenability.

Practical Value of the Three-Layer Architecture

1. Guiding Precision Diagnosis: From "symptom matching" to "mechanism tracing" — Phenotype data → Functional assessment → Root cause tracing → Individualized diagnosis.

2. Guiding Stratified Intervention: Multi-level, multi-target treatment strategies — phenotype layer intervention (rapid relief), functional layer intervention (restore capabilities), root cause layer intervention (reverse mechanisms).

3. Guiding Preventive Medicine: From "early detection" to "early intervention" — advancing the intervention window by 10-20 years.

4. Guiding Aging Research: A unified framework for integrating fragmented knowledge — constructing a panoramic map of "aging-disease."

Criteria for Layer Assignment

Criterion 1: Causal Position — Root cause layer is "cause," functional layer is both "cause" and "effect," phenotype layer is "effect."

Criterion 2: Universality/Specificity — Root cause layer is highly universal, functional layer is moderately universal, phenotype layer is highly specific.

Criterion 3: Measurability and Clinical Accessibility — Phenotype layer is easily measurable, functional layer requires specialized assessment, root cause layer requires advanced technology.

Criterion 4: Time Scale of Intervention — Phenotype layer: hours to days; functional layer: weeks to months; root cause layer: months to years.

Part II: The Inevitable Deduction from the First Principle of Life to the Three-Layer Framework of Root Cause Medicine

Author: Xiong Jianghui

Introduction

What is the essence of life? What is the essence of disease? How can we truly understand and cure disease?

I have proposed the First Principle of Life: Life is an ensemble of environmental adaptation capabilities. This article will demonstrate how, starting from this first principle, the three-layer framework of Root Cause Medicine can be inevitably deduced.

I. The First Principle of Life: An Ensemble of Environmental Adaptation Capabilities

Life = Ensemble of Environmental Adaptation Capabilities

Life is not a single adaptive capability, but a multi-level, multi-dimensional ensemble of adaptive capabilities at the cellular, organ, system, and organismal levels.

II. Deductions from the First Principle to the Nature of Disease

Disease = Decline, dysregulation, or loss of environmental adaptation capabilities

Treating disease should not merely eliminate symptoms, but should restore and enhance adaptive capabilities.

III. The First Layer of Inevitability: Phenotype Layer

By observing the external manifestations of adaptation failure. This is the phenotype layer — including subjective symptoms, objective signs, and examination abnormalities.

The phenotype layer only tells us "adaptation has failed," but does not tell us "why it failed" and "where it failed."

IV. The Second Layer of Inevitability: Functional Layer

An "ensemble" means there exist multiple different adaptive capability systems. The functional layer includes metabolic adaptation, immune adaptation, detoxification, repair, stress adaptation, digestion, and circulatory functions.

V. The Third Layer of Inevitability: Root Cause Layer — Capacity Reserve Information

Capacity Reserve Information encompasses genetic information, epigenetic information, structural integrity, energy reserves, material reserves, microbiome information, and regulatory information.

DNA Methylation serves as the epigenetic storage mechanism for capacity reserve information — regulating gene expression, recording environmental information, and storing adaptive memory. It can even be transgenerationally inherited.

VI. The Causal Chain and Logical Closure

Causal chain: Root cause layer → Functional layer → Phenotype layer

Diagnostic chain: Phenotype layer → Functional layer → Root cause layer

VII. Why Exactly Three Layers?

Logically, these three layers are both necessary and sufficient — corresponding to What (phenomenal), How (mechanistic), and Why (essential) levels of scientific cognition.

VIII. Clinical Case: Diabetes

Phenotype Layer: Fasting blood glucose 7.8 mmol/L, HbA1c 7.2%

Functional Layer: HOMA-IR 4.5 (insulin resistance)

Root Cause Layer: Chronic low-grade inflammation, gut microbiota imbalance, vitamin D deficiency, mitochondrial dysfunction, oxidative stress

Three-Layer Integrated Treatment: Root cause interventions (gut microbiome, inflammation, vitamin D, mitochondrial support, lifestyle) + functional support + phenotype monitoring

Results after 6 months: Fasting blood glucose 5.2 mmol/L, HbA1c 5.6%, HOMA-IR 1.8 — discontinued medication, maintained through lifestyle and nutritional interventions alone.

This is the power of Root Cause Medicine: not suppressing symptoms, but rebuilding capacity reserves.