to ourselves, the people around us, and the world at large.

We can call this optimistic thesis the 'clear pane' theory of the mind,

iImplying that we are able to look out onto the world

pretty much as if through an undistorted, and blemish-free pane of glass.

Yet a long tradition in philosophy has sought to warn us of a far trickier truth.

The school of thought, known as skepticism, that began in Ancient Greece in the third century B.C.

proposed that a great many of our solid-seeming sensory first impressions

should not be assumed to be accurate

and must instead be submitted to the laborious process of rational unscrambling.

Far from our minds being clear panes, they're full of scratches, blind spots and warps.

To be wise, therefore, means for the skeptics to strive to be permanently vigilant

no matter how much we're inclined to misunderstand reality

by trusting our first feelings.

One tiny instance of our distorting minds that particularly fascinated the Greeks

was a strange phenomenon that occurs when a stick is partially submerged in water.

It immediately seems as if the stick angles into a "V" just at the point where it meets the surface.

But, if we pull the stick out, we'll see that it's of course, still straight.

The skeptics took this tiny example as a gateway to a vast truth:

that our senses are humbling fallible.

The way things appear to us is often simply not how they, in fact, really are.

Skeptical ideas were to be the leading force behind the development of modern science.

In the middle of the 16th century, the Polish philosopher and astronomer Capernicus

demonstrated that whatever our senses might have suggested to us for hundreds of thousands of years,

according to logical reasoning, the truth is that the sun does not, in fact, revolve around the earth.

But the skeptics weren't only interested in the errors we fall into when doing astronomy--

they were fascinated by our tendencies to fall into error in our personal lives

under the influence of our emotions.

For example, our minds are seldom free of the influence of moods:

a kind of emotional weather that scouts over our mental horizons

normally without us having any understanding of where these moods have come from,

when they might lift,

or even that they exist.

However, these moods can have a decisive impact on our ideas.

We might in one mood consider ourselves fortunate

with a bright-lit future, and feel grateful to those around us.

And then, a few hours later, without anything in the outer world having changed,

another mood might lead us to a whole set of re-evaluation of almost everything about us.

Devilishly, part of what it means to be subject to a mood is not to realize that we are in its grip.

We simply feel that our friends, who we liked quite a lot yesterday, are no good.

And our job, which once offered us so much, is absurd.

Tiredness can be a particularly powerful agent that silently and invisibly perverts our judgement.

The 19th century skeptic, Friedrich Nietzsche, remarked,

"When we are tired, we are attacked by ideas we thought we'd conquered long ago."

Though crucially, it's extremely rare and counter intuitive to judge that it really might be tiredness

that's affecting our outlook rather than certain objective facts in the world.

We are keener to conclude that we've suddenly developed a deep resentment against humanity

that we urgently need to get to bed.

Lust can similarly play with our judgement,

leading us to see sensitivity, kindness, and a decent alternative to our current partner.

But there is, in truth, just an exceptionally beautiful profile

and perhaps not much else.

As the German skeptical philosopher, Arthur Schopenhauer, wryly concluded,

"Immediately after population, the devil's laughter can be heard."

Appreciating how flawed our minds are

forms the basis upon which the story on emotional skepticism is founded.

This skill, defined as a cautious awareness of the misleading power of our feelings on our judgement

Having surveyed the fragilities of our minds,

the Ancient Greek skeptical philosophers

recommended that we learn to develop an attitude of what they called "Epoche,"

translated as "reserve," or "suspension of judgement."

But where of our tendencies to error

we were never to rush into decisions.

We were to let our ideas settle

so that they could be re-evaluated at different points in time

and we were to be especially vigilant about the impact of sexual excitement and tiredness

on the formation of our plans.

For a range of historical reasons,

we've collectively been extremely reluctant to recognize the benefits of emotional skepticism.

The romantic movement of the 19th century

bequeathed us that beguiling would often distract solution

but it's our emotions that we always find us guides to the truth.

But we would've gone a long way to counteract the problems of our minds

if we sometimes do ourselves the honor of not listening to our feelings.

Instead, waiting for some unhelpful moods to pass

and accepting that we are at heart, highly viscous bags of saline solution

who stare out at reality via a highly unreliable and distorted pane of glass

and must therefore frequently suspend judgement, moderate our impulses,

watch over our diet, and strive to get to bed early.