Research on Bitcoin scaling technology based on complex adaptive system theory Since its inception, Bitcoin's scalability has been a key challenge to its large-scale adoption. Based on a deep understanding of Bitcoin as a Complex Adaptive System (CAS), this paper discusses four possible future technical expansion directions of the Bitcoin network from its core components. We believe that Bitcoin is a CAS made up of three interacting formal subsystems: Individual sovereignty subsystem: With a 1:1 digital state and individual self-mapping as the core, it is embodied in the Unspent Transaction Output (UTXO) model in Bitcoin. Each UTXO represents independent asset ownership and control for a specific user. P/NP Reality-Aware Subsystem: Implemented through asymmetric computational puzzles (P-problems) and easy-to-verify solutions (NP problems), Bitcoin's Proof-of-Work (PoW) mechanism is at its core. PoW enables machines to perceive and record the objective reality of transactions in a decentralised manner, maintaining the consistency of the ledger. Consensus intermediary subsystem of trust code: As an open and transparent distributed ledger, blockchain provides a notarisation and execution environment without trusting a third party through preset code rules and consensus mechanisms, ensuring the transparency and immutability of transactions and data. Based on the above understanding of the essence of Bitcoin CAS, we can systematically sort out the following four main directions of technology expansion: 1. UTXO-based individual sovereign application extensions Bitcoin's UTXO model exhibits unique advantages in asset management, such as clear ownership and a high degree of privacy. The existing BRC-20 and Omni Layer protocols are the first attempts to issue and manage assets on Bitcoin based on the UTXO mechanism. However, the potential of UTXOs goes far beyond that. Scientific logic: At its core, UTXO lies in its explicit state ownership and atomic state transition. This feature is highly compatible with the needs of use cases such as Decentralized Identity (DID). Mapping the various attributes and credentials of DIDs into a UTXO-like structure allows users to have full autonomy over and manage their digital identity. Every update of identity information or transfer of credentials can be regarded as a state transfer of UTXO, thus ensuring the immutability and traceability of identity data. Technology Path: This requires extending the existing UTXO structure to allow richer metadata to be stored in a single "UTXO" and designing new transaction types to support the updating and management of DID-related states. At the same time, incorporating Layer 2 technology can improve the efficiency and scalability of such applications. 2. Horizontal scaling based on P/NP perceptual reality Bitcoin's PoW mechanism successfully achieves decentralised consensus and an objective record of transaction history. However, the potential of PoW can go beyond its application in the cryptocurrency space and allow for a broader "reality perception" to scale horizontally to serve the real economy. Scientific Logic: The essence of PoW is to anchor real-world workloads or resources by consuming verifiable computing resources. Drawing on this idea, various mechanisms for "Proof of Physical Resource/Work" can be designed. Verifying the existence, state, or workload of specific resources (e.g., storage, bandwidth, energy) in the physical world through cryptography can provide credible proofs for decentralised cloud computing, Internet of Things, energy management, and more. In addition, PoW-based verifiable computation can ensure the correctness of distributed computing tasks and the reliability of results. Technology Path: This requires interdisciplinary collaboration, combining knowledge from cryptography, physics, engineering, and other fields to design proof mechanisms that can reliably map the properties and behaviours of the physical world to the digital world. 3. The continuous evolution and application deepening of Blockchain technology As the cornerstone of Bitcoin, blockchain technology has been widely recognised for its advantages in transparency and trustworthiness, and has been successfully applied in areas such as decentralised finance (DeFi). While the underlying technology is maturing, its development is far from stopping. Scientific logic: Through the cryptographic hash chain and consensus mechanism, the blockchain ensures the non-tampering of transaction data and the non-repudiation of history, so as to build a transparent and credible value transfer and information recording network. The success of DeFi is precisely to take advantage of the transparency of blockchain, reducing the information asymmetry and intermediary risk in the traditional financial system. Technology Path: Future development will focus on improving blockchain scalability (e.g., Layer 2 technology, sharding), interoperability (cross-chain protocol), privacy protection (zero-knowledge proof, homomorphic encryption), and modular design to meet the needs of more complex application scenarios. Fourth, the construction of an innovative decentralised system based on the Bitcoin CAS model We believe that Bitcoin's most valuable legacy is not a single technological breakthrough, but rather its clever integration of individual sovereignty, decentralised consensus, and transparent rules into a robust and adaptive system architecture. Learning from Bitcoin's CAS design ideas and applying them to build a new decentralised system is the most promising development direction in the future. Scientific logic: Bitcoin's success lies in the synergy between its various subsystems, which together maintain the stability and security of the network. Drawing on this systematic design thinking, we can design a new decentralised system with similar core characteristics for different application scenarios. For example, decentralised social networks can borrow from UTXO's ownership model and PoW-like content governance mechanisms; New DAOs can leverage UTXOs for more granular governance and incentive design; A decentralised supply chain management system can learn from UTXO's traceability capabilities and "physical proof-of-work" authenticity verification. Technical Path: This requires us to deeply understand the core design principles of Bitcoin CAS and abstract and generalise them for application in different domains. This involves innovative thinking and design of specific implementations of individual sovereignty, decentralised consensus, and transparent rules. conclusion The expansion of Bitcoin should not only be limited to tinkering with and optimising its existing technology, but also need to understand the internal logic and interaction of its core components from its essence as a complex adaptive system. By in-depth research and learning from Bitcoin's innovative solutions in individual sovereignty, reality perception and trust consensus, and applying its systematic design ideas to a wider range of fields, we are expected to open up more potential and disruptive decentralised application prospects, and truly integrate blockchain and cryptocurrency technology into the broader digital economy and social life. We call on academia and industry to pay attention to the in-depth study of the Bitcoin CAS model and actively explore innovative solutions based on this framework.