David Hume coined a sceptical, reductionist viewpoint on causality that inspired the logical-positivist definition of empirical law that "is a regularity or universal generalization of the form 'All Cs are Es' or, whenever C, then E".
[1] The Scottish philosopher and economist believed that human mind is not equipped with the a priori ability to observe causal relations.
In A Treatise of Human Nature Hume coined two definitions of the cause in a following way: We may define a CAUSE to be An object precedent and contiguous to another, and where all the objects resembling the former are placed in like relations of precedency and contiguity to those objects that resemble the latter.
[2]also fixed eight general rules that can help in recognizing which objects are in cause-effect relation, the main four are as following: (1) The cause and effect must be contiguous in space and time.
(3) There must be a constant union betwixt the cause and effect.