Scientific Method. A Practical Guide.

Introduction

The question “how do you know that?” can be irritating.
Not because it is wrong — but because it is difficult to answer honestly.

In most cases, the answer sounds confident, but is based not on verification, but on habit, experience, or someone else’s conclusions.

The problem is not that we don’t know.
The problem is that we don’t know — and yet we are confident that we do.

How knowledge is formed

Knowledge does not appear as a finished answer.
It is assembled gradually — from observations, errors, and attempts to explain what is seen.

The history of science is not a sequence of discoveries, but a chain of refinements.
New data rarely overturn everything at once. More often, they reveal the limitations of previous explanations.

Even simple questions may require years of observation and verification.
Sometimes — a lifetime.

What we often mistake for knowledge

what “everyone says”
what “has always been done”
what resembles a familiar case
what conveniently explains what we see

All of these can be useful.
None of them, by themselves, constitute evidence.

The most dangerous error is not the absence of knowledge,
but confidence in an explanation that has not been tested.

This becomes especially evident in fish pathology

The same symptom may have different causes.
Similar changes may arise from entirely different processes.
The presence of a sign does not imply understanding of the mechanism.

Gas bubbles are not always gas bubble disease.
White spots are not always the same parasite.
Hyperemia is not always inflammation.

Without a method, observation easily turns into speculation —
and speculation into confident explanation.

What the scientific method is in practice

The scientific method is not a formula or a set of terms.
It is a way of working with reality.

It includes:

observation
recording conditions
comparison of signs
testing alternative explanations
rejecting convenient explanations when they fail under scrutiny

It does not guarantee the correct answer.
But it reduces the likelihood of being confidently wrong.

What changes with this approach

fewer “instant diagnoses”
less ritual treatment
better understanding of causes rather than symptoms
greater caution in conclusions

Most importantly, it allows distinguishing observation from interpretation.

The scientific method does not make the work easier — it makes it more honest.
It does not eliminate errors — but it prevents them from going unnoticed.
It is not a way to always be right — it is a way to avoid being confidently wrong.

Core principles

The method does not begin with an answer.
It begins with observation.

1. Data collection

Observation must be separated from interpretation.

Record what is actually observed:

fish behavior
external appearance
changes over time
environmental conditions

Do not explain — describe.
Not “the fish is sick”, but “the fish is lying on the bottom, respiration is increased”.

2. Recording conditions

Every observation has context. Without it, data lose meaning.

Record:

temperature
water parameters
system changes
feeding
transfers, stress

The same symptom under different conditions represents different situations.

3. Keeping records

Memory distorts sequence. Records do not.

Record:

what happened
when
under what conditions
what changed after intervention

Without records, it is impossible to distinguish cause from consequence.

4. Comparing signs

A single sign does not constitute a diagnosis.

Meaning arises from their combination.

Compare:

which signs match
which contradict
what is missing despite expectations

The absence of a sign can be more important than its presence.

5. Testing alternatives

The first explanation is usually the most convenient.
And often wrong.

Ask:

what else could explain this?

If at least one alternative exists, it must be considered.

6. Minimal intervention

Intervention changes the system — sometimes faster than we can understand it.

The more simultaneous actions:

the harder it is to identify the cause
the higher the risk of incorrect conclusions

Fewer actions, but with understanding of their effect.

7. Evaluating outcomes

Every action is a hypothesis. The result is its test.

Improvement does not always mean the cause was identified.
Lack of improvement does not always invalidate the hypothesis.

Evaluate:

what changed
how quickly
how stable the effect is

Important

The method is not a sequence of steps to complete.
It is a way of thinking applied at every stage.

It does not require complex equipment.
It requires accuracy in observation and honesty in conclusions.

This is what distinguishes knowledge from assumption.

References

Ferguson, H.W., 2006. Systemic Pathology of Fish: A Text and Atlas of Comparative Tissue Responses in Diseases of Teleosts, 2nd ed. Scotian Press, London.
Kuhn, T.S., 2012. The Structure of Scientific Revolutions, 4th ed. University of Chicago Press, Chicago.
Noga, E.J., 2010. Fish Disease: Diagnosis and Treatment, 2nd ed. Wiley-Blackwell, Ames.
Popper, K.R., 2002. The Logic of Scientific Discovery. Routledge, London.

FAQ

Why is one symptom not enough for diagnosis?

Because the same sign may result from different processes.

What matters more: experience or method?

Method. Experience without verification often leads to errors.

Why avoid immediate treatment?

Because intervention alters the system and obscures the cause.

What does “testing alternatives” mean?

Considering other possible explanations, not just the first one.

Can mistakes still occur?

Yes, but the method reduces confident errors.