Was Thomas Jefferson a rationalist?

Question

If so, did he include his views in the Declaration of Independence?

Answer 1

I believe that Thomas Jefferson was more of an Idealist than a rationalist. My belief for that is that during the revolutionary war he held firm to the beliefs of the revolution, believing that despite all the set backs eventual the colonies would prevail based upon the sheer ideals portrayed in the Declaration of Independence.
And again when looking at his support for the french revolution after gaining Independence, his long dispute with John Adams over the powers of confederation verse a centralized government. In my opinion these had to be strong ideals to guide him, even when the french revolution turned in to a blood bath, it took him a while to change his opinion about that matter, and taking into account the manner in which he prosecuted the Barbary pirate war and how it was settled. I think he was a person of ideals and he continued to develop these ideals and reevaluate his line of thinking and often when the reality clashed with his Ideals it took him time to sort these out. I think that the rationalist in him was that with his feelings of freedom and mankind he continued to participate in slavery when he had to have the belief that this was contrary to his own beliefs. In this he was a rationalist for despite knowing that slavery was wrong and contrary to his own constitutional beliefs he continued in this endeavor and only corrected this in his will.

Answer 2

Absolutely.
"We hold these truths to be self-evident: that all men are created equal, that they are endowed by their creator with certain unalienable rights and among these are life, liberty and the pursuit of happiness..."
TJ did not believe in fate, but what we make of our lives. TJ did not believe in an active and omnicient deity, but rather in a "creator" who may or may not still be around, but probably doesn't interfere at all in how his creation runs ... like a kid setting a clockwork toy going and then laughing and clapping as it whirrs.
That was Thomas Jefferson. He was arguably the smartest president the USA has ever had.
Cheers.