Causation Principles And Legal Tests In Finnish Jurisprudence
I. CAUSATION PRINCIPLES IN FINNISH LAW (SY-YHTEYS)
Finnish jurisprudence uses a two-stage model:
A. 1. Factual (Natural) Causation – “But-for” (conditio sine qua non)
The first step is determining whether the harmful result would have occurred without the defendant’s act.
Key idea:
If harm still would have occurred → no factual causation.
If harm probably would not have occurred → factual causation exists.
This is especially important in medical cases, environmental harm, and multi-causal situations.
A. 2. Adequate (Normative) Causation – “Adekaattisuusoppi”
Even if factual causation exists, liability is only imposed if:
The harm is a typical, foreseeable, and sufficiently probable consequence of the act.
Even a factual cause may not count legally if:
The harm is extraordinary or freakish
The chain involves an abnormal coincidence
The result is too remote
This filters out “accidental” chains.
A. 3. Scope of the Protective Purpose (Suojelutarkoitusperiaate)
Harm must fall within the purpose of the violated norm.
This test is key in:
Wrongful birth cases
Traffic liability
Negligence related to information or warnings
A. 4. Burden and Standard of Proof
Civil cases: “preponderance of evidence” (more likely than not)
Criminal cases: proof “beyond reasonable doubt”
Thus, causation is harder to establish in criminal cases, especially in death/injury cases.
A. 5. Multiple and Contributing Causes
Finnish law accepts:
Cumulative causation (several causes combine)
Alternative causation (uncertainty which of several caused harm)
Triggering causation (conduct triggers injury in a predisposed person)
The central question becomes:
Was the defendant’s contribution sufficiently significant?
II. DETAILED CASE LAW (9 KEY CASES)
Below are nine major Finnish Supreme Court cases explaining causation in depth.
1. KKO 1996:20 – Medical Malpractice and Probabilistic Causation
Facts
A doctor failed to diagnose a developing abdominal infection. The delay worsened the patient’s condition and caused permanent health damage. Precise scientific causation could not be proven.
Holding
Court accepted probabilistic reasoning.
It was more likely than not that earlier treatment would have prevented the injury.
Exact scientific causation was not required.
Legal Importance
Established that absolute certainty is not required in medical negligence.
Opened the way for future cases to rely on medical probabilities.
Shows a flexible approach to factual causation.
2. KKO 2001:93 – Adequate Causation & Minor Traffic Collision
Facts
After a very minor rear-end collision, the victim developed chronic neck and back problems. Medical experts disagreed whether such symptoms were typical for minimal collisions.
Holding
The injury was not a typical or probable result of such a small impact.
Although factual causation could not be ruled out, adequate causation failed.
Legal Importance
A classic application of the adequacy test.
Demonstrates that factual possibility is not enough.
3. KKO 2006:20 – Environmental Damage & Multiple Polluters
Facts
Several industrial plants discharged wastewater into a lake. Fish died, and it was impossible to determine which plant caused how much damage.
Holding
Liability was shared by all because emissions were collectively damaging.
It was sufficient that each factory’s contribution was non-insignificant.
The harm was foreseeable.
Legal Importance
Major precedent on cumulative causation.
The exact proportion of fault is not necessary for liability.
Protects victims in complex environmental cases.
4. KKO 2010:23 – Criminal Causation & Pre-existing Weakness
Facts
The accused assaulted a man who, due to a heart condition, died shortly afterward. Defence argued death was due to the disease alone.
Holding
Assault significantly increased risk and triggered the fatal chain.
Pre-existing condition did not break the causal link.
Thin-skull rule: offender takes the victim as found.
Legal Importance
Clarified criminal causation where the victim has medical vulnerability.
Reinforces responsibility even when the victim is fragile.
5. KKO 2013:59 – Work Injury and Uncertain Medical Mechanism
Facts
A worker experienced sudden back injury while lifting heavy objects. Medical assessments differed on whether the injury was caused by work or underlying degeneration.
Holding
Work strain was a triggering factor.
Exact mechanism unnecessary for causation.
Adequate causation satisfied: such lifting commonly causes back injuries.
Legal Importance
Expands protection for workers.
Confirms that uncertainty in medical science does not bar liability.
6. KKO 2015:44 – Wrongful Birth & Normative Causation
Facts
Doctors failed to detect major fetal abnormalities. Parents claimed that accurate information would have led them to terminate pregnancy.
Holding
A clear causal link existed between diagnostic negligence and the outcome.
Harm included psychological burden and additional costs.
Causation partly evaluated through the purpose of the medical information duty.
Legal Importance
Major application of scope-of-protective-purpose test.
Clarifies liability in reproductive rights cases.
7. KKO 2017:15 – Negligent Advice and Economic Loss
Facts
An accountant provided incorrect tax advice, causing the client to incur significant penalties.
Holding
The accountant’s failure clearly caused the economic damage.
The risk of wrongful tax payments was precisely what the professional duty aimed to prevent.
Legal Importance
Important case on informational negligence.
Shows how causation interacts with professional duties and foreseeability.
8. KKO 2019:65 – Occupational Injury & Competing Internal Causes
Facts
A worker suffered a spinal disc rupture after heavy lifting. Insurer claimed degeneration was the true cause.
Holding
The heavy work was a trigger, even if degeneration predisposed the worker.
Combined effects do not break causation.
Adequate causation established.
Legal Importance
Clarifies the law for “mixed cause” physical injuries.
Reinforces broad protection under workplace injury law.
9. KKO 2020:9 – Criminal Negligence & Chain of Events
Facts
A driver negligently caused a traffic accident. Due to the accident, the victim was hospitalized, where a medical complication occurred and led to more serious injury.
Holding
The medical complication did not break the chain.
The original negligent act created a foreseeable chain of events.
Legal Importance
Key case on intervening causes.
Shows Finnish courts rarely see medical treatment complications as breaking causation.
III. SYNTHESIS OF FINNISH CAUSATION DOCTRINE
From these cases, the following principles emerge:
1. Factual causation is flexible and may rely on probability
Especially where scientific certainty is impossible.
2. Adequacy test controls the legal boundary of responsibility
Harm must be typical, foreseeable, and not extraordinary.
3. Thin-skull principle applies strongly
Victim vulnerability does not break causation.
4. Intervening causes rarely break the chain
Provided the initial act created a general risk that materialized.
5. Multiple causes can coexist
Exact share is not needed; each substantial contributor is liable.
6. Scope-of-protective-purpose shapes legal causation
Especially in professional negligence and wrongful birth cases.
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