Syncretistic generalization is no better than selecting groups by random.
Syncretistic: This is, for all intents and purposes, synonymous with random selection. If you ask me to divide up the class into two groups, I may randomly place people into each group and then name the groups “males” and “females.”
This is a step forward in that I am recognizing the concept of a group, but it is not of great practical value and could actually create some problems if the group members happen to be teenagers.
The syncretistic part relates to the underlying, if not sub conscious, factors governing each selection. They are fleeting and not necessarily expressible in words. So if you ask a young child, who was sorting blocks, why he included certain blocks in a group, he might not be able to tell you. It could have been that he noticed a chip onk the first block, the second was easy to reach, the third was his favorite color and the fourth had a figure of a dog on it, etc.