 The Stoic understanding of the soul further involves core epistemological ideas. Human beings have “impressions” (imprints or alterations of the soul). We acquire the views we hold by assenting to impressions; in every given case, we can assent to an impression, negate it, or withhold judgment. Since this is in our power, it is in our power to become wise (by assenting only to cognitive impressions, which represent things precisely as they are). Human action is generated through “assent” to practical impressions; such assent sets off impulse (hormê). If there is no external impediment, impulse leads to action. It is in our power to become virtuous, because assent is in our control; we decide how we act. Seneca discusses these and related issues with the help of a term that has no equivalent in Greek Stoicism: voluntas.