[1] Often, ad hoc hypothesizing is employed to compensate for anomalies not anticipated by the theory in its unmodified form.
Scientists are often skeptical of theories that rely on frequent, unsupported adjustments to sustain them.
This is because, if a theorist so chooses, there is no limit to the number of ad hoc hypotheses that they could add.
[2][better source needed] Albert Einstein's addition of the cosmological constant to general relativity in order to allow a static universe was ad hoc.
Although he later referred to it as his "greatest blunder", it may correspond to theories of dark energy.