How does scientific knowledge grow? This question has occupied a central place in the philosophy of science, stimulating heated debates but yielding no clear consensus. Many explanations can be understood in terms of whether and how they view the expansion of knowledge as proceeding through the accretion of scientific concepts into larger conceptual structures. Here we examine these views empirically by analysing 2,605,224 papers spanning five decades from both the social sciences (Web of Science) and the physical sciences (American Physical Society). Using natural language processing techniques, we create semantic networks of concepts, wherein noun phrases become linked when used in the same paper abstract. We then detect the core/periphery structures of these networks, wherein core concepts are densely connected sets of highly central nodes and periphery concepts are sparsely connected nodes that are highly connected to the core. For both the social and physical sciences, we observe increasingly rigid conceptual cores accompanied by the proliferation of periphery concepts. Subsequently, we examine the relationship between conceptual structure and the growth of scientific knowledge, finding that scientific works are more innovative in fields with cores that have higher conceptual churn and with larger cores. Furthermore, scientific consensus is associated with reduced conceptual churn and fewer conceptual cores. Overall, our findings suggest that while the organization of scientific concepts is important for the growth of knowledge, the mechanisms vary across time.

科学知识是如何增长的？这个问题在科学哲学中占据了中心位置，引发了激烈的辩论，但没有达成明确的共识。许多解释可以从他们是否以及如何将知识的扩展视为通过科学概念的积累到更大的概念结构中进行来理解。在这里，我们通过分析来自社会科学 （Web of Science） 和物理科学 （American Physical Society） 的 2,605,224 篇跨越五十年的论文，实证地检验了这些观点。使用自然语言处理技术，我们创建了概念的语义网络，其中名词短语在同一篇论文摘要中使用时变得相互关联。然后，我们检测这些网络的核心/外围结构，其中核心概念是密集连接的高度中心节点集，而外围概念是与核心高度连接的稀疏连接节点。对于社会科学和物理科学，我们观察到越来越僵化的概念核心伴随着边缘概念的激增。随后，我们研究了概念结构与科学知识增长之间的关系，发现科学工作在核心具有较高概念流失率和较大核心的领域更具创新性。此外，科学共识与减少概念流失和减少概念核心有关。总的来说，我们的研究结果表明，虽然科学概念的组织对知识的增长很重要，但机制会随着时间的推移而变化。