Our minds possess by nature an insatiable desire to know the truth.

An acute first-class brain is the finest asset anyone can have- and, if we want to be happy, it is an asset we must exploit to the uttermost.

For while we are enclosed in these confinements of the body, we perform as a kind of duty the heavy task of necessity; for the soul from heaven has been cast down from its dwelling on high and sunk, as it were, into the earth, a place just the opposite to godlike nature and eternity. But I believe that the immortal gods have sown souls in human bodies so there might exist beings to guard the world and after contemplating the order of heaven, might imitate it by their moderation and steadfastness in life.

The spirit is the true self.

When I consider the wonderful activity of the mind, so great a memory of what is past, and such a capacity of penetrating into the future: when I behold such a number of arts and sciences, and such a multitude of discoveries hence arising,--I believe and am firmly persuaded that a nature which contains so many things within itself cannot be mortal.

Memory is the receptacle and sheath of all knowledge

Sweet is the recollection of difficulties overcome.