Is a locution for using instinct and logic.
Although both are used to predict future occurrences, they don’t work the same way. While one requires the use of facts and patterns, the other needs only the recognition of one’s gut feelings.
Regardless of which you trust the most, your judgment and predictions will likely be flawed. But your chance of making a better call is greater with logic.
However, our instincts hold greater significance when testing new waters, a first-time situation.