“Says who?”
This is from Frank J. Sheed
“We look at the bread the priest uses in the Sacrament. It is white, round, soft. The whiteness is not the bread, it is simply a quality that the bread has; the same is true of the roundness and the softness. There is something there that has these and other properties, qualities, attributes- the philosophers call all of them accidents. Whiteness and roundness we see; softness brings in the sense of touch. We might smell bread, and the smell of new bread is wonderful, but once again the smell is not the bread, but simply a property. The something which has the whiteness, the softness, the roundness, has the smell; and if we try another sense, the sense of taste, the same something has that special effect upon our palate.
In other words, whatever the senses perceive-even with the aid of those instruments men are forever inventing to increase the reach of the senses- is always of this same sort, a quality, a property, an attribute; no sense perceives the something which has all these qualities, which is the thing itself. This something is what the philosophers call substance; the rest are accidents which it possesses. Our senses perceive accidents; only the mind knows the substance”
Allow me to be more clear: While the accidents of bread and wine remain, so too the Real Presence remains. When those accidents no longer remain, neither does the Real Presence.
Protestants are fond of quoting the Council of Trent. It’s all set forth in the conciliar documents.
Even that does not say that all accidents are perceived by the senses. It just says "if you perceive it by sense, it's an accident." It does not say "if and only if".