On a simple level, the 'laws' of 'cause and effect' seem to be straightforward and self-evident - if you drop a 'priceless' ceramic vase onto a concrete floor, it will very probably break. (ref.) But examined in greater detail, and on larger timescales, causality reveals many levels of uncertainty and vagueness.

For example, in the broken vase scenario, what processes lead to the existence of the vase in the first place? The ceramic was presumably fired from clay in a kiln. Where did the clay come from? What provided the energy to melt it? So, on timescales longer than the second or two in which the vase broke, the problem unravels into an infinite examination of every single possible detail of how the scenario arose. A clearly impractical task. And, looking forwards into the future, can we accurately describe every possible consequence of the vase's destruction? Again, impossible to say.

Such questions have been examined since the time of the Ancient Greek philosophers. And, more recently by thinkers such as Bertrand Russell - who in 1912 wrote On The Notion Of Cause for the Proceedings of the Aristotelian Society, Vol. 13, pp. 1-26

In the following paper I wish, first, to maintain that the word "cause" is so inextricably bound up with misleading associations as to make its complete extrusion ^{[ sic.?]} from the philosophical vocabulary desirable; secondly, to inquire what principle, if any, is employed in science in place of the supposed "law of causality" which philosophers imagine to be employed; thirdly, to exhibit certain confusions, especially in regard to teleology and determinism, which appear to me to be connected with erroneous notions as to causality."

Since Russell's time, the picture has become even more complicated. Quantum mechanicsplugin-autotooltip__plain plugin-autotooltip_bigQuantum mechanics

This is a general note about the yet-to-be-understood complexities of quantum theory

Here are some 20th century quotes from eminent scientists regarding its extreme counter-intuitiveness :

"• “Those who are not shocked when they first come across quantum theory cannot possibly have understood it.” has proved that - at least at the scale of atomic particles - effects don't necessarily have to be preceded by causes, and all effects are simply questions of probability. In addition, Chaos Theoryplugin-autotooltip__plain plugin-autotooltip_bigChaos Theory

unknowable

Chaos Theory is the concept that the behaviour of some complex dynamical systems (e.g. global weather patterns) can be extremely sensitive to tiny changes in initial conditions.

Any large-scale system which has a complex set of interacting feedback and feed-forward loops can become chaotic - thus making accurate and specific long-term predictions about the system unreliable, if not impossible. has shown that effects can very dramatically change due to imperceptibly small variations in starting conditions. For example, if you were to roll a large round stone down a very rocky slope, it will quite probably end up in a different position each time you did so. Again, subject to probabilities.

For a modern-day plain-language essay on some of the many current viewpoints and uncertainties about causality, see Chaos and cause at Aeon.