Since the theory of synchronicity is not testable according to the classical scientific method, it is not widely regarded as scientific at all, but rather as pseudoscientific or an example of magical thinking. However, it is doubtful that Jung would have considered the theory to be scientifically testable.

A broader objection that is related to science but not to testability is that positing an underlying mechanism for meaningfully interpreted correlations is to develop an overly complicated explanation for the phenomenon at hand meaningful coincidence, which might be better explained by simple coincidence.

The suggestion is that given the vast array of observed phenomena, and given our innate interest in and awareness of coincidence, it is inevitable that such phenomena will come about.