On the origin of the concept clade

Plesiomorphy and apomorphy is analogous to before and after, but…where did now disappear?

The answer is that Hennig pointed at an apomorphy (i.e., an after) calling it a now (i.e., a monophyly) defining now (i.e., monophyly) as apomorphy (i.e., as after).  It is analogous to pointing at a white object calling it gray and defining gray as white. Everything is OK, except the name (i.e., monophyly is not apomorphy, and gray is not white), and, since monophyly is generic to apomorphy just like gray is generic to white, this nominal (i.e., conceptual) confusion also confuses the generic with the specific.

The conceptual confusion itself was later renamed clade, thus legitimating a confused approach within biological systematics (i.e., cladistics or cladism), thus creating the impossible task of defining its fundamental confusion, i.e., ambiguity, unambiguously (like in Wikipedia). 

The concept clade did thus generically originate as a conceptual confusion of X and Y in X, later renaming X as Z. It means that the concept Z (i.e., clade) is consistently defined as X (i.e., monophyly) and Y (i.e., apomorphy), that is, as in the starting point. Z (i.e., clade) is nothing but a confusion of X (i.e., monophyly) and Y (i.e., apomorphy). 

This confusion appears to lead biological systematics from an ambiguous approach into an unambiguous, but it actually instead leads from an ambiguous approach into a doubly ambiguous approach (both across and along). Two ambiguities do thus not add up as one unambiguity, but as two ambiguities.

The concept clade is thus a doubly ambiguous conceptual confusion. This fact is difficult to understand, but anyone with some sense can make a good guess if something sensible can arise from an approach that rests on a doubly ambiguous concept. The alternative is empirical science, resting on the unambiguous concept object, which cladistics (cladism) denies. The choice is thus between cladistics (cladism) and empirical science.