XI. Others have refused to credit the evidence of their senses; but not so grossly, but that they have condescended to make use of them to direct their actions in the common affairs of civil and human life. They govern themselves by them for the purpose of living, but not for that of philosophizing. The information of their senses serves them to chuse the useful, and avoid the pernicious, but not to determine the theory of an object. XII. The arguments they assign for this distrust of their senses in the last instance, may be reduced to three. The first is, the distinction we should admit between the impression which objects make on our senses, and the absolute essence or quality contained in the objects themselves. For example, we say that hemlock is bitter. If by this expression, we mean to declare, that this herb makes on our palate a determined impression or sensation, which we call bitterness, we speak properly; but if we mean to say that the herb in itself contains an absolute quality, which we describe by the same name, we speak improperly; for if this was the case, all the animals who relish hemlock would find it bitter; but it happens otherwise, for the goats are fond of it, and eat it greedily. In the same manner do all those reason, who adopt this mode of arguing with respect to all other sensible species. They say, the fire produces in us that kind of impression, which we call heat; but that we ought not from thence to conclude, that it is hot in itself. Thus although by approaching very near to it, it produces pain in us, still it is not sensible of any itself. Therefore we ought not for this reason, to say the fire contains pain, it being at most only capable of occasioning pain; neither ought we to call it hot, but only capable of producing heat; nor can we call it hot but by equivocation, as we say, Medicine is healthy, because it produces health in the animal.