Does demonic temptation always precede sin?

Here is a question, or rather a series of questions, that I recently received:

Can man commit sin without being tempted by the devil? Could Adam have ate the Apple without outside pressure or influence? Can man, with only his conscience and free will, commit an act against God, or do all human actions against God have a connection to Satan? Satan went against God with out outside influence, right?

As far as I can tell, there are really three questions here:

1) Could the first sin of man have come apart without the tempting of the devil?

2) Can any sin come about without the tempting of the devil?

3) Did the devil go against God without outside influence?

Let's look at these one at a time.

In response to whether the first man could have sinned without the temptation of the devil: In the original sin of Adam we know for certain that the devil was directly involved, but whether or not it had to be so is a matter of speculation. I am unaware of any definitive answer on this, but based on my own opinion, I am going to say that the devil's agency was not necessarily needed, and this for three reasons:

i) As we shall see below, man can still even now sin without the devil's temptation. Therefore, he could have done so in regards to the original sin as well. Concupiscence after the Fall makes man more disposes to sin, but I don't see any reason to say that he could not have sinned prior to the Fall without the devil - he could have still fallen to pride, envy, or some similar sin.

ii) Scripture always speaks of original sin as originating in Adam. Of course, the devil was there, but the fault is layed with Adam, emphasizing Adam's disobedience rather than the devil's temptation (see Romans 5:12, "For by one man sin entered the world..") The fact that the stress is layed on Adam means that it was within Adam's power to obey or not obey. Satan could tempt him to disobey, but the power over the choice was implicitly always with Adam - the devil just exacerbated a dilemma that already existed - whether or not to eat of the fruit.

iii) The fact that the devil himself sinned without external aid makes this point as well. If a pure intellect (angel) can sin of his own accord, presumably an incarnated spirit (man), who is lesser than an angel, can fall the same way.

What about question two, whether man can ever sin without a prior tempation of the devil? St. Thomas takes up this exact question in STh I-II, Q. 80 Art. 4. He says that the devil can be said to be the cause of all human sins only indirectly, insofar as he led the first man to sin and because it is by the consequences of original sin we are tempted to commit actual sins. However, it often happens that we sin of our own immoderate appetites, regardless of the devil. Here is St. Thomas' take on it:

"The devil is the occasional and indirect cause of all our sins, in so far as he induced the first man to sin, by reason of whose sin human nature is so infected, that we are all prone to sin: even as the burning of wood might be imputed to the man who dried the wood so as to make it easily inflammable. He is not, however, the direct cause of all the sins of men, as though each were the result of his suggestion. Origen proves this (Peri Archon iii, 2) from the fact that even if the devil were no more, men would still have the desire for food, sexual pleasures and the like; which desire might be inordinate, unless it were subordinate to reason, a matter that is subject to the free-will" (STh I-II, Q. 80 Art. 4).

We certainly know that Satan can tempt people directly, but this need not always be the case. We could also invoke the verse from the Epistle of St. James: "But every man is tempted, when he is drawn away of his own lust, and enticed" (Jas. 1:14).

As to the third question, whether or not any external agent was active in Satan's own sin, we have to say no, insofar as before the fall of Lucifer there was no evil, external agent that could act upon him. I'd say it is certain that Lucifer fell of his own accord. Wisdom 2:24 speaks of the devil sinning through "envy", which is something completely internal, as is pride, the other sin commonly used to explain Satan's fall (as in Isaiah 14:13-15 and in the following verse from Ezekiel:

"You were the anointed cherub who covers, And I placed you there. You were on the holy mountain of God; you walked in the midst of the stones of fire. "You were blameless in your ways from the day you were created, until unrighteousness was found in you. "By the abundance of your trade you were internally filled with violence, and you sinned; Therefore I have cast you as profane from the mountain of God. And I have destroyed you, O covering cherub, from the midst of the stones of fire. "Your heart was lifted up because of your beauty; You corrupted your wisdom by reason of your splendor. I cast you to the ground; I put you before kings, that they may see you" (Ezekiel 28:14-17).

Interesting questions. By the way, any readers who want to submit questions are more than welcome - it helps in weeks when I am short on topics to blog about!