The Hidden Debate Shaping Our Understanding of Life
What is the "function" of a heart? To pump blood, you might say. But is that because pumping blood is what hearts do, or is it the reason hearts exist in the first place? This seemingly simple question hides a deep philosophical rift that shapes how we understand life itself. For decades, scientists and philosophers have argued over the true meaning of "function" in biology, often treating different interpretations as incompatible rivals. But groundbreaking new research suggests that our very thinking about life's purposes is naturally pluralistic—and that this diversity of perspectives is not a weakness, but a strength.
In biology, the concept of "function" is fundamental, yet surprisingly fragmented. The philosophical debate largely divides into two compelling but conflicting camps:
This view claims a trait's function is what it was historically selected for by evolution. The function of eyes is to see because ancestors with light-sensitive cells had more offspring. This explains why we have eyes today and distinguishes true functions from mere accidents (hearts make noise, but that's not their function) 1 .
This perspective defines function by what a component currently contributes to the organism or larger system. It emphasizes the present role a part plays in maintaining the whole, regardless of evolutionary history 1 .
These views often clash. Consider a trait that now does something different from its evolutionary past—which is its "true" function? The emerging field of synthetic biology complicates this further by intentionally designing biological systems, blending natural evolution with human intention 1 .
An eye-opening 2025 study directly investigated how both biology experts and novices think about biological functions across different contexts—single-celled organisms, multi-celled organisms, and synthetic biology 1 .
Researchers discovered something surprising: both experts and novices are natural "function pluralists." Rather than consistently adhering to one philosophical view, people readily switch between backward-looking and forward-looking concepts of function depending on context 1 . This pluralism isn't confusion—it's a flexible reasoning strategy our minds use to understand biological complexity.
| Account | Core Idea | Strengths | Limitations |
|---|---|---|---|
| Selected Effects | Function is what evolution selected the trait for | Distinguishes function from accident; explains trait existence | Relies on historical narratives; problematic for new synthetic biology |
| Causal Role | Function is current contribution to a larger system | Works for novel traits; emphasizes present organization | Cannot explain why trait exists; misses normative aspect |
| Organizational | Function maintains conditions for its own existence | Applies to natural and designed systems; avoids history conflicts | Complex formulation; less intuitive |
The groundbreaking research exploring function pluralism employed a sophisticated qualitative methodology to uncover how people naturally think about biological functions 1 :
Researchers presented participants with biological scenarios across different contexts—natural organisms (both single-celled and multi-celled) and synthetically engineered biological systems.
The study included both biology experts and novices, allowing comparison between trained scientific thinking and intuitive biological reasoning.
Through carefully designed questions and analysis, the research team identified when participants switched between different concepts of function, particularly between backward-looking (historical selection) and forward-looking (current role) views.
The experimental design specifically tested whether people treated different function concepts as incompatible or freely used them together—the key indicator of true pluralism 1 .
The findings challenged conventional wisdom about biological reasoning:
Experts and novices showed remarkable similarity in their function reasoning across most contexts, suggesting pluralism may reflect fundamental cognitive patterns rather than trained scientific practice 1 .
Both groups demonstrated significant function pluralism, freely combining backward and forward-looking concepts rather than treating them as mutually exclusive 1 .
The one area where expert-novice differences emerged was synthetic biology, likely because introducing intentional design creates new conceptual challenges that novices navigate differently 1 .
| Research Finding | Expert Response | Novice Response | Interpretation |
|---|---|---|---|
| Function Pluralism | Clearly demonstrated | Clearly demonstrated | Pluralism is cognitively natural |
| Backward/Forward-Looking Compatibility | Combined these views | Combined these views | Philosophical "incompatibility" may be overstated |
| Synthetic Biology Context | Distinctive response pattern | Different approach | Intentional design introduces unique conceptual challenges |
Just as laboratories require specific tools and reagents to conduct experiments, conceptual research employs its own methodological toolkit to investigate how we think about biological functions:
| Tool/Reagent | Function in Research | Application Example |
|---|---|---|
| Contextual Scenarios | Presents different biological contexts to test conceptual consistency | Comparing function reasoning across natural vs. synthetic biology |
| Semi-Structured Interviews | Allows deep exploration of individual reasoning processes | Understanding how experts justify function assignments |
| Qualitative Coding | Systematically identifies patterns in reasoning data | Categorizing different function concepts used spontaneously |
| Concept-Conception Distinction | Separates core concept from specific implementations | Analyzing unity and diversity in niche concept understandings 7 |
| Interdisciplinary Collaboration | Integrates philosophical and biological expertise | Developing research designs that address both conceptual and empirical questions |
The recognition of function pluralism has concrete implications for cutting-edge science and public policy:
When engineers design biological systems with intentional functions that may differ from evolutionary history, whose "function" counts? Pluralism helps navigate these conflicts 1 .
How the public understands and accepts synthetic biology may depend on aligning intuitive versus expert concepts of function, particularly regarding intentional design 1 .
Recognizing natural pluralism can improve how scientists explain their work to funders, policymakers, and the public by speaking to multiple concepts of function.
This pluralistic approach mirrors patterns seen in other biological concepts. For instance, research on the "individualized niche" concept reveals a similar balance—a unified core concept with multiple distinct conceptions, each valuable for different research questions 7 .
The 2025 research on function pluralism offers a refreshing perspective on biological thinking. Rather than forcing a choice between competing function concepts, the evidence suggests we naturally think about life's purposes in multiple ways simultaneously. This cognitive flexibility isn't a flaw—it's a feature that allows us to navigate biology's complexity.
As we enter an era of increasingly sophisticated biological engineering, embracing this plurality may be crucial. It allows scientists to honor evolutionary history while pursuing innovative designs, and helps bridge the gap between expert knowledge and public understanding. The function of "function", it turns out, is multidimensional—and our thinking is beautifully equipped to handle that complexity.
This article synthesizes findings from recent peer-reviewed research on function pluralism in biological reasoning, particularly drawing from open-access studies published in 2025.