I'm wondering about clarity within meditation. I seem to have diminished greatly the agitation I experience, but there is a degree of mental sinking, of mental tiredness which I have a hard time eliminating. This tiredness seemingly makes the meditation session a meditation on the feeling of lethargy and laxity, and I am having a really really hard time ridding myself of this dullness. I've tried antidotes of uplifting thoughts, I've tried having equanimity towards the sensations, and remaining with them. I've tried tightening the breath, focusing sensations more closely on a specific area close to the nostrils. Yet, I've not managed to rid myself of this dullness, and I wonder if I should keep meditating while it is within my mindstream. Any advice would be appreciated.
It sounds like you might be experiencing the third hindrance for meditative progress, i.e. "Sloth and Torpor" (thina-middha). This hindrance is a mental tiredness that arises and makes the mind cloudy and unwieldy.
The Five Hindrances are briefly:
"Sensory desire (kāmacchanda): the particular type of wanting that seeks for happiness through the five senses of sight, sound, smell, taste and physical feeling.
Ill-will (vyāpāda; also spelled byāpāda): all kinds of thought related to wanting to reject, feelings of hostility, resentment, hatred and bitterness.
Sloth-torpor (thīna-middha): heaviness of body and dullness of mind which drag one down into disabling inertia and thick depression.
Restlessness-worry (uddhacca-kukkucca): the inability to calm the mind.
Doubt (vicikicchā): lack of conviction or trust".
There is some information about Sloth and Torpor and how to overcome it here.
Other solutions given could be to splash cold water in the face and then return to meditation or getting up and do walking meditation instead. The thing is that one has to balance the meditation practice meaning that if sloth and torpor arises then one must do the opposite in order to counter act it. In this case it would be to energize the mind.
This talk is highly recommended it gives a lot of information and antidotes to all of the hindrances.
I've tried having equanimity towards the sensations, and remaining with them. I've tried tightening the breath, focusing sensations more closely on a specific area close to the nostrils. Yet, I've not managed to rid myself of this dullness, and I wonder if I should keep meditating while it is within my mindstream. Any advice would be appreciated.
The Vipassana method, as in Pacalā Sutta, based on sensations to fight sleepiness is:
“Nothing is worth clinging to”
When this was said, the venerable Mahā Moggallāna said this to the Blessed One: “In what way, bhante, in brief, is a monk freed through the destruction of craving, that is, one who has reached total perfection, the total security from bondage, the total holy life, the total consummation, the highest amongst gods and humans?”
“Here, Moggallāna, the monk has learned that nothing is worth clinging to. And, Moggallāna, a monk has learned that nothing is worth clinging to, thus: he directly knows all things [he directly knows the nature of the all]. Having directly known the nature of all things, he fully understands all things.
Having fully understood all things, he knows whatever feelings there are, whether pleasant, painful or neither painful nor pleasant.
As regards to those feelings, [Section on Disillusionment and Revulsion (Nibbida) follows]
he dwells contemplating impermanence in them;
he dwells contemplating dispassion [fading away of lust] in them;
he dwells contemplating ending (of suffering) in them;
he dwells contemplating letting go (of defilements).
When he dwells contemplating impermanence in them, contemplating dispassion in them, contemplating ending in them, contemplating letting go, he does not cling to anything in the world. Not clinging, he is not agitated; being not agitated, he himself surely attains nirvana.
Also see: The Five Mental Hindrances and Their Conquest Selected Texts from the Pali Canon and the Commentaries compiled and translated by Nyanaponika Thera
I wonder if what you are feeling is tiredness (or sloth/torpor as the sutta would call it) and not something else. A lot of people, especially Westerns, very much prize the mental acuity and stimulation that you would have when, say, writing computer software, reading a riveting book, writing a SE response (heh), or watching an engaging movie. While focus is an important part of meditation, the phenomenology of one-pointed samadhi is very different from these kinds of activities. It doesn't have the same kind of sharpness. In fact, when compared to activities that promote mental arousal, meditation can feel a little dull at first.
It sounds to me that you are actually just experiencing your mind relaxing. I'm going to double down on that as you mentioned that agitation has been a problem for you in the past. It's highly unlikely that the pendulum has swung so far in the opposite direction. A much more likely cause is that your mind is starting to rebel and cling desperately to stimulation. The very last thing you want to do is arouse it again. Doing that will undo the work you've put in quelling your agitation. Just sit and watch the breath. It sounds like you are doing fine.
Meditative states are like putting on a new pair of underwear. As Garth says in Wayne's World, at first they can feel uncomfortable and constrictive. But after a while, they become a part of you! :-)