Your mind is like a bird. Let it be and it will fly out any window into the great blue sky.
The Torah doesn't provide any signs to determine if a bird is kosher. It just provides us a list of birds that we must not eat—most of them predators.
Over the ages, much confusion has arisen concerning the identity of those forbidden birds. So the rule is, before eating some new bird, you need to ask a master kosher bird-trapper if he has received a tradition about this bird.
That's another way our minds are like birds.
A non-kosher inner animal is easy to spot. But there's no known way for a mind to determine whether it hasn't just flown out the kosher window and into the absurd.
Unless you have a teacher, a master of catching birds and bringing them back home. One who holds the keys to all the accumulated wisdom of millennia.
And you have the humility to just ask.
I always was led to believe un-kosher birds, as a rule-of-thumb, tend to be carrion birds, or at least, even if predatory, can soemtimes be onvolved in eating of carrion. Which parallels the food rule against the eating of carrion, and carrion-related creatures.
For novices, please don't take me literally, anyone, till you find a confirmation of this, or not.