It is direct and absolute. It places us in contact with things and beings, while reason only apprehends ideas and concepts.
This may be as I believe a faulty and perhaps dualist approach to perception and rationality. However one knows what he means.
The heart is the 'illative sense' of The Grammar of Assent according to Steinmann:
"It is a capacity (writes Newman) of entering with instinctive
correctness into principles, doctrines and facts, whether they
be true or false, and of discerning promptly what conclusion from them is necessary, suitable, and expedient „ . . .It is an intimate understanding of an assemblage of intellectual data .....
I have already ventured to say that our belief in the extended material world follows on an inference from our perception of particular objects through their phenomena, as these phenomena actually come before it us, or even... from our experiences of the sensible phenomena of self, It is by the illative sense that we come to this conclusion, which no logic can reach.
Illative means arising" out of, consequently in Newman's sense it is the power of immediately- grasping the consequences of a given set of data. It is this which prevents philosophers from going wrong. It is also the sense that they can get that there is something not quite correct in the judgements of another thinker.
Bergson turned intuition into a philosophical method:
"It is not necessary in order to reach intuition to move out of the sphere of the senses and consciousness, Kant's mistake was to think that it was.--. Let us go back to the origins of our power of perception and we shall find that we possess knowledge of a new kind without there being any need to appeal to new faculties,.....
The origin of our powers of perception, that's the famous hard question. Is it about qualia? Let's say that the fuzzy red of a ripe tomato presents itself but not the concept 'tomato'. That concept is not the stuff of any operation of the senses in the sense that though it may be out of the senses it is not equivalent to them. What is the source of the identity which the unschooled in philosophy recognise between the object out there and the mental modification? The advaitins hold that the identity is not numerical but a matter of substratum.
I leave the obvious 'what about' to see if you've been paying attention.