Algimantas asked:

I am Deputy Chief of the Criminological Research Department at the Lithuanian Institute of Law.
While writing my PhD thesis, I have faced one problem I am not sure I can solve myself. So maybe
you could just advise me the way of analysis. The problem shortly sounds as follows: I have to prove
that two facts are just elements of the same process.

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How do we decide whether we are dealing with one and the same process or two different
processes? I kick a tin can, and as I do so there is a flash of lightning and moments later a clap of
thunder. Unless I credit myself with supernatural powers, I must assume that my kicking the tin can
was one process, and the thunder and lightning was another process. It was pure coincidence that
they happened at the same time.

On the other hand, science teaches us that in the case of thunder and lightning what seem to be two
processes happening at different times, are in fact one and the same process. We are seeing and
hearing the electrical discharge of millions of volts from storm clouds. The only reason we hear the
thunder after the lightning is that sound travels more slowly than light.

Then we have to consider the case where one process causes another, different process. The
process of lightning striking the roof of the house caused the process of the house fire. However, the
house fire was not part of the process of the lightning strike. There is a clear dividing line between
one process and the other.

If you asked me how, in general, one proves that two facts, or two processes are causally related, I
doubt whether there would be anything that one could usefully say in purely general terms.
Establishing causes and effects is a matter of discovering the true, or best explanation for a given set
of phenomena. Here's a concrete example. A worker in a plastics factory develops cancer and sues
the company for criminal negligence, claiming that his cancer resulted from his handling carcinogenic
substances. In court, the company might try to argue that there is no proof that the substances used
in their manufacturing process cause cancer, or they might admit that the substances are
carcinogenic but deny that they could have been the cause of cancer in this particular instance. There
are familiar ways to test such claims in the courts.

But that was not your question. You asked how one proves that two facts are part of the same
process.

When are we likely to raisethe question whether facts A and B are part of one and the same process,
rather than merely being causally related to one another? Here is where I wish you had given me a
concrete example to work from. Try as I might, I just can't think of a legally relevant case where it
matterswhether we are dealing with one and the same process or not! In law, what matters are
causes and effects, how one attributes responsibility for a given fact, not how one individuates
processes.

Geoffrey Klempner