The Becoming of Possibility: 04/02/26

Thursday, 2 April 2026

Signal Without Semiosis: Value, Selection, and the Misreading of Meaning in Biology — 1 What Biologists Mean by “Signal”

Before questioning the concept of the signal, we need to be precise about how it is actually used.

Biologists are not careless. The term signal is not applied arbitrarily. It is typically defined with some rigour, and within evolutionary biology it carries a fairly specific meaning.

So the task of this post is not to critique, but to reconstruct the concept in its strongest form.

Only then can we ask what kind of explanation it provides.

The standard definition

In contemporary evolutionary biology, a signal is generally understood as:

a trait or behaviour that has evolved because it affects the behaviour of other organisms.

This definition already contains several important elements:

the signal is observable (a colour pattern, a sound, a movement)
it is correlated with some underlying condition or state
it elicits a response in another organism
and crucially, it is selected for because of that response

The last point is decisive.

A signal is not just something that happens to be noticed.

It is something that exists, in part, because it is noticed.

Signals and selection

This brings us back to familiar examples.

The peacock’s tail is not merely a decorative feature.

It persists because it influences mating behaviour.

Similarly:

bird songs influence territorial and mating responses
warning colouration influences predator behaviour
courtship displays influence reproductive outcomes

In each case:

a trait is produced
another organism responds
and that response feeds back into evolutionary selection

The signal is thus embedded in a loop:

production → response → selection → stabilisation

Information and correlation

Biological discussions of signalling often invoke the notion of information.

A signal is said to “carry information” about:

health
strength
reproductive status
environmental conditions

This is typically grounded in correlation:

brighter colours correlate with better condition
more elaborate displays correlate with fitness
specific calls correlate with types of threat

From this perspective, the signal is informative because it is reliably associated with something else.

The role of the receiver

Equally important is the role of the receiver.

A signal is only a signal if there is:

a system capable of responding to it
in a way that affects behaviour

Receivers are often described as:

detecting
interpreting
or decoding

the signal.

But even in more restrained accounts, the key point is that:

the behaviour of the receiver is systematically altered by the presence of the signal.

Functional accounts

Putting this together, signals are typically characterised functionally:

they do something in the system
they influence behaviour
they contribute to fitness outcomes

Their existence is explained not by what they are in isolation, but by the role they play in these dynamics.

This is why signals are often distinguished from:

cues — features that provide information but have not evolved for that purpose
noise — features that have no systematic effect on behaviour

A signal, in contrast, is functionally integrated into the system of interaction.

What this account does not require

At this point, we can make an important observation.

Nothing in the definition so far requires:

representation
symbolic relation
or a system of meaning

What is required is:

correlation
responsiveness
and selection

That is enough to produce:

stable patterns
reliable responses
and coordinated outcomes

The quiet expansion

And yet, in practice, the concept of signal rarely stays at this minimal definition.

From “affects behaviour,” it expands to:

“carries information”
“communicates”
“expresses”
“represents”

This expansion is often implicit.

The same term—signal—is used across all these levels, without marking the shift.

As a result, a concept grounded in:

evolutionary function

comes to support claims about:

meaning and communication

Where we now stand

We are now in a position to state the situation clearly.

Biologists use signal to refer to:

traits that are correlated with certain states
that elicit responses in other organisms
and that are stabilised through selection because of those responses

This is a robust and well-motivated concept.

But it is also a concept that:

does not, in itself, require semiosis.

Transition

The next step is to examine how this concept is interpreted.

Does correlation plus response justify talk of meaning?

Does functional influence amount to communication?

Or are we moving too quickly from:

responsiveness
to
representation?

To answer this, we turn to a foundational case—sexual selection—and ask what kind of explanation it actually requires.

Signal Without Semiosis: Value, Selection, and the Misreading of Meaning in Biology — 0 The Seduction of the Signal

Biology is full of signals.

The language is everywhere:

animals signal their fitness
traits communicate information
organisms send messages to one another
behaviours are interpreted by receivers

From the elaborate display of the peacock’s tail to the urgency of an alarm call, the natural world is routinely described as a dense field of communication.

At first glance, this seems not only intuitive, but unavoidable.

Something is going on here.

Patterns are produced.

Responses are elicited.

Coordination emerges.

What else could this be, if not communication?

The familiar example

Consider the peacock’s tail.

A male displays an extravagant fan of colour and pattern.

A female observes.

She preferentially mates with certain males over others.

This is commonly described as a case of signalling:

the tail signals fitness.

The logic appears straightforward:

the tail correlates with some underlying condition
the female responds to the tail
the trait evolves because of that response

From this, a further step is taken almost automatically:

the tail means something.

It is taken to stand for, or represent, the fitness of the male.

The unnoticed step

But something has happened here that is rarely examined.

We have moved from:

correlation
to response
to selection

and then, almost without noticing:

to meaning

That final step is not trivial.

It introduces a different kind of explanation altogether.

Two kinds of account

There are, in fact, at least two ways to describe what is happening in such cases.

One account says:

certain traits are differentially taken up within a system
preferences shape outcomes over time
patterns stabilise through repeated selection

This is an account in terms of coordination and value.

Another account says:

one form stands for another
something is expressed and something else is understood
a relation of meaning is established between them

This is an account in terms of semiosis.

The two accounts are not the same.

But in biological discourse, they are very often treated as if they were interchangeable.

The inflation of the signal

The term signal sits precisely at this point of slippage.

It begins innocently enough:

a feature that elicits a response

But it quickly expands:

a feature that carries information
a feature that communicates
a feature that represents

Each step adds conceptual weight.

By the end of the process, what began as differential responsiveness has become a fully-fledged semiotic system.

Why this is compelling

The move is not arbitrary. It is compelling for good reasons.

responses are often reliable
correlations are often stable
patterns are often repeatable

From within such regularity, it is natural to infer:

something is being conveyed.

The world begins to look like it is full of messages.

A suspicion

But we should pause here.

Because the appearance of meaning does not guarantee its presence.

It is possible—indeed likely—that:

what is being described as signalling is doing explanatory work that does not require semiosis at all.

In other words:

coordination may be occurring without communication
alignment may be achieved without meaning
selection may operate without representation

The problem

If this is the case, then a significant portion of biological explanation rests on an unexamined assumption:

that differential response implies meaning.

This series takes that assumption as its starting point.

Not to reject it outright, but to question it systematically.

What is at stake

The issue is not terminological.

It is not about whether we should use words like “signal” or “information.”

It is about whether the phenomena being described actually require a theory of meaning.

If they do, then biology must account for semiosis properly.

If they do not, then the language of signalling may be obscuring the mechanisms at work.

A way forward

To address this, we will proceed by separating two domains that are often conflated:

value — the dynamics of selection, coordination, and differential uptake
meaning — the semiotic organisation of relations within a system of distinctions

By keeping these distinct, we can ask more precise questions:

what work is being done by value?
what work, if any, is being done by meaning?
and under what conditions does one become the other—if it ever does?

Orientation

This series will not begin by assuming that biological signals are meaningful.

It will begin by asking:

what must be in place for something to count as semiosis at all?

Only then can we return to familiar cases—the peacock’s tail, alarm calls, coordinated behaviours—and determine whether they are:

instances of meaning
instances of value
or something more complex

Closing

The natural world is often described as if it were speaking.

Before we accept that description, we should ask:

is anything actually being said?

Or are we, perhaps, hearing meaning where there is only coordination?

The distinction matters.

And once drawn, it may change how we understand not only biological systems, but the place of meaning within them.

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